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Things Network Gateway Diy Build

What is the Things Network

The Things Network originated in Amsterdam, Netherlands in 2015.

The idea was to create a crowd funded Internet of Things network, that was open to the public.

The network uses LoraWAN spread spectrum wireless technology to enable data from environmental sensors, to get onto the Internet.

The network has quickly expanded through crowd funding and volunteers installing their own ‘Gateway’ devices.

The Gateway devices receive data that has been transmitted from sensors, and puts that data onto the Internet cloud.

Sensors can include pollution monitoring devices, Smart Parking detectors, flood warning sensors etc.

The LoraWAN that I mentioned is the wireless technology that allows the transfer of data from the sensor (which might be in a field a mile from the Gateway), to the receiving Gateway device.

LoraWAN Characteristics

Lorawan is suitable for applications that only require small amounts of data to be transferred at a time. Therefore LoraWAN would not be suitable for transmitting video from a CCTV camera (WIFI would be more suitable).

Data transfer is also quite slow.

What LoraWAN excels at is allowing small amounts of data to be sent over relatively long distances (such as 10Km), while consuming very low battery power.

The good communications range, and low battery power consumption make it ideal for the Internet of Things, or IOT for short.

To start using the Things Network, there are a few options available.

Firstly you can buy a ready made indoor Gateway that the initiators of the Things Network have now manufactured.

A second option is to buy a Gateway designed for commerical LoraWAN use. These Gateways are often designed for outdoor use, and feature weatherproof construction.

A third option to get onto the Things Network, if there is no local Gateway within range, is to build your own Gateway.

There are a few options and ways to build a Gateway, including using an RF board from RAK Wireless.

The option that I used to build my Gateway, uses an 880A LoraWAN Concentrator board from IMST of Germany.

The RF Concentrator board is controlled and connected to the Internet via a Raspberry Pi.

Full details for construction are given below.

Building the Gateway

For beginners to building their own gateway, I would recommend joining, or founding a local Things Network .

The Lorawan Gateway that I am going to describe here, is designed to operate on the Things Network, however other lora networks can easily be installed.

The main components that you will need are:-

1) A Concentrator board from IMST of Germany. The Concentrator board is the wireless communications part of the system, responsible for receiving the wireless data signals, from the remote environmental sensors (Air quality sensors etc).

2) A small computer to store the software that controls the Concentrator board. We are going to use the UK designed Raspberry PI 3.

A Micro SD Card, for holding the software used by the Raspberry PI.  A small 4 GB card is fine.

3) A suitable Antenna (or Aerial), with pigtail connecting cable.

4) A suitable 2 Amp rated power supply, with a micro USB connector.

5)  7 Female to Female connecting leads, suitable for raspberry PI.

4) A suitable case, to house the components.

The first thing I need to make you aware of is the risk of static electricity, to your IMST ic880a Concentrator and Raspberry PI.

Static can damage the sensitive electronic components, therefore it is advisable to take precautions, such as not touching the board components, and wearing an anti static wrist strap.

The first thing you need to do is to format the micro SD card, that will be fitted to the raspberry PI, to hold the gateway software.

The SD card association has a free piece of software, for Windows PC and Mac, to do this. My card was already formatted, so I skipped this step.

The next step is to burn the actual software that will power your gateway, onto the Raspberry PI.

To do this, I used https://etcher.io/    

I first installed Etcher onto my  linux desktop computer. As most people use Windows PC, or Mac, you will need to find a suitable alternative to Etcher.

I also downloaded the operating system needed to run the Raspberry Pi, which is called Raspbian Stretch Lite , onto my desktop PC.

Put your micro SD card into your computers micro SD card reader. If your computer (like mine) does not have a card reader, then external USB plug in ones can be purchased cheaply (I got mine from my local Asda supermarket for £6).

Fire up Etcher, or whatever card  burning software you prefer, and select the copy of Raspbian Stretch Lite , that you previously downloaded to your PC.

Follow the instructions, and burn the operating system software onto the micro SD card.

Once you have successfully burned your Raspbian Stretch Lite, onto your SD card, insert it into the Raspberry Pi (the slot is on the underside of the Pi).

The next thing to do is to connect your Raspberry Pi to a suitable monitor (I used a TV, that had a HDMI connection), and also connect a USB keyboard, power supply, and mouse.

The power supply should be 5 Volts DC, and Raspberry Pi power supplies are widely available. I used a USB phone charger, with 5 Volts output, and a current rating of 2000mA.

Boot up your Raspberry Pi (connect the power), and you will see lots of computer code scrolling across your screen (if you have done everything successfully, so far).

When the Raspberry Pi asks you for a user name and password, use the following default ones (the  bit after the  ‘ : ‘ ).

Username: Pi

Password: Raspberry

After you have successfully logged in, type:

 sudo raspi-config

Numbered options will now hopefully be on your monitor screen.

Select [5] Interfacing Options, and then P4 SPI

Then select [7] Advanced Options , and then [A1] Expand Filesystem.

You now need to exit the raspi-config utility, either by hitting the ‘CTRL’  and  ‘X’ keys, or by typing sudo reboot

Next you are going to Configure the locales and time zone.

Type this in, to set the locales, and follow instruction.

sudo dpkg-reconfigure locales

Next, type this in to set time zone.

sudo dpkg-reconfigure tzdata

The next stage is to update the raspberry Pi software, do this by typing:

sudo apt-get update

Then install any upgrades to the operating system software, by typing sudo apt-get upgrade

Next we are going to install Git , which is needed to be able to download the Things Network software from Github.

Type:

sudo apt-get install git

The next step is to create a user called TTN (the things network).  This user will eventually replace the default raspberry pi user, which we will delete.

sudo adduser ttn

Then:    sudo adduser ttn sudo

Logout, by typing logout

Once you have logged out, log back in using the user name and password that you have just set up, when you added a user.

You can now delete the default Raspberry Pi user, by typing

sudo userdel -rf pi

Set the WIFI  SSID and password details, which can be found on the back of your home router / Hub (usually).

To set the WIFI details type

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf 

Once you have typed in the above text, you should see some code on the screen. Add the following to the end of the existing code, making sure that you enter your SSID and password details, in place of the shown text.

network=

{
ssid="The_SSID_of_your_wifi"
psk="Your_wifi_password"

}

Now we are going to clone the installer from Github. This will download the software which runs the gateway, from the Github repository.  Type each of the following three code lines into your Pi, one at a time, hitting the return key after each line of code.

  git clone -b spi https://github.com/ttn-zh/ic880a-gateway.git ~/ic880a-gateway
  cd ~/ic880a-gateway
  sudo ./install.sh spi

Identifying the LoraWAN Gateway

The software will give the gateway the default name of ttn-gateway.

This however may need to be changed, to prevent issues with other Things Network Gateways within wireless range.

Wiring it Up

The next step is to connect the  Concentrator board, to the Raspberry Pi, and also connect the antenna.

The components including the antenna should be mounted in a protective box,  and the antenna connected to the Concentrator board.

It is very important that the Concentrator board is not powered up, with no suitable antenna connected, of damage could occur to the board.

Once the antenna is connected, then the next step is to connect the Concentrator to the Raspberry Pi.

Connect using female to female connecting wires, as follows:

iC880a Concentrator pin Description RPi physical pin
21 Supply 5V 2
22 GND 6
13 Reset 22
14 SPI CLK 23
15 MISO 21
16 MOSI 19
17 NSS 24

IMPORTANT DISCLAIMER:

It is important that you identify the correct pins, by referring to the manufactures data sheets (Both IMST & Raspberry Pi).

We accept no liability for loss or damage caused, by following these information only instructions.

For help, and to learn more about the Things Network Gateway, or what the Things Network can do, why not get in touch with me.

@acraigmiles

www.craigmiles.co.uk

Craig Miles (C) 2018 -2019 , all images and content, unless stated separately.

Featured

Preventive Maintenance For Electric Motors

Preventative Maintenance

Preventive maintenance programmes  are the key to reliable, long-life operation of electric motors.
Whilst AC Induction Motors are particularly reliable in service, almost all electrical equipment requires periodic planned inspection and maintenance. Planned preventative maintenance ensures electrical motors, and starters are kept in good working condition at all times. This is critical for businesses that rely on electric motors. A scheduled routine of motor inspection should be carried out throughout the motor’s life. Periodic motor inspection helps prevent serious damage to motors by locating potential problems early.

Periodic Inspections

Planned electric motor maintenance programmes are designed to help prevent breakdowns, rather than having to repair motors after a breakdown. In industrial operations, unscheduled stoppage of production or long repair shutdowns is expensive, and in marine shipping environments, a potential safety issue. Periodic inspections of motors are therefore necessary to ensure best operational reliability.

Preventive maintenance programmes require detailed checks to be effective. All motors onsite (factory, ship etc) should be given their own individual identification (ID) number and have a record log. The record log is usually computerised these days. The motor records kept should identify the motor, brand, inspection dates and descriptions of any repairs previously carried out. By record keeping, the cause of any previous breakdowns can help indicate the cause of any future problems that might occur.

All preventative maintenance programmes should refer to the equipment manufacturer’s technical documentation prior to performing equipment checks.

There are simple routine maintenance checks that can be applied to three phase induction motors, which help ensure a long service life to a motor. 

The Simple checks that can be carried out, include a review of the service history, noise and vibration inspections. Previous noise issues could for example be due to motor single phasing. Previous vibration may have been due to worn bearings, which allow the Stator to turn. Other checks include visual inspections (damage and burning), windings tests (insulation resistance & continuity), brush and commutator maintenance (dc motors) and bearings and lubrication.

Inspection frequency and the degree of inspection detail may vary depending on such factors as the critical nature of the motor, it’s function and the motor’s operating environment. An inspection schedule, therefore, must be flexible and adapted to the needs of each industrial or marine environment.

(c) Craig Miles 2019.  craigmiles.co.uk

For bespoke electrical training with Craig, call  +44 (01522) 740818

Featured

Induction Motor Servicing Tips For Ships & Factories

Induction Motor Servicing.

Induction motors are used widely in factories and on ships.

They are very reliable machines, but faults can develop over time.

That is why you need Induction motor servicing to be carried out.

Potential faults include burnt out Stator windings, worn bearings, and water damage which causes low insulation resistance.

This article covers tips on Induction motor servicing.

Safety & Isolation of supply of induction motors.

Correct electricity supply isolation procedures are critical for safety.

Taking a casual approach to electrical supply isolation can prove fatal.

Three phase Induction motors, typically operate in factories at around 400 Volts AC (Alternating Current).

Marine installations typically operate at an even higher 440 Volt Alternating Current (440 VAC).

It is important that no one works on a piece of three-phase machinery, such as an Induction motor unless you are qualified to do so.

On board ship, proper authorisation, such as a valid ‘permit to work’, signed off by a ships chief engineer, should be in place before carrying out any Induction Motor servicing.

On land seek authorisation from the responsible senior managers, with appropriate responsibilities for safety.

For work to be carried out aboard Ships, permission from someone such as the Chief Engineer is appropriate.

Once permission has been gained, and the appropriate paperwork issued, only then can work commence.

Certainly in the marine environment, and normally onshore as well, ‘locks and tags’ will be issued.

The lock is to ensure that once an isolator switch has been turned off, no one can switch it back on accidentally.

The ‘tag’ details who has isolated the supply, and is working on that circuit.

Only the person who has been issued with the lock and tag set, can remove them.

Double check that circuit is dead.

Don’t assume that just because you have locked and tagged the appropriate electrical isolator, that you are safe to work on a circuit.

The isolator may be incorrectly labeled, or even worse, you have taken someone else’s word for it.

Before you stick your fingers in, and potentially kill yourself, you need to use an appropriate device to check that the circuit is safe to work on.

Induction motor servicing can be dangerous, if proper procedures are not followed.

There are three possible devices that can be used:

  1. Test Bulb
  2. Multimeter / Voltmeter
  3. Line Tester

Firstly lets look at the test bulb as an option.

A test bulb with appropriate leads and clips attached, can provide indication of a live circuit, but has a flaw.

If the bulb filament breaks, then you could falsely assume that the circuit is safe to work on, with possibly fatal outcomes.

The second option is the Multimeter / Voltmeter which these days will probably be a ‘solid state’ digital type, rather than the older analogue types, which are commonly referred to as ‘AVO’s’ in the UK.

The Multimeter / Voltmeter being ‘solid state’ is more likely to be a bit more reliable than, a filament bulb tester. However it still may be broken, and you would not necessarily know. An example being the test probe wires may be ‘Open Circuit’.

The third option, the ‘Line Tester’, will provide the most reliable indication of whether a circuit is safe. Therefore this is the preferred option.

The reason that a line tester is safer is because it contains four separate Neon bulbs (some modern ones are LED).

The bulbs light up according to how high the voltage is, for example a 400 VAC supply would light not only the 400VAC light, but the lower voltage indicator lights as well.

So imagine that the 400VAC indicator bulb has broken.

The lower voltage indicator bulbs will still light up, for example the 230VAC and 110VAC indicator bulbs.

Therefore the engineer will still have an indication that there is voltage in the circuit, and can investigate further.

Before using a Line Tester you should use a ‘proving unit’. A proving unit is a small hand-held device capable of producing a voltage such as 250 Volts.

The Line tester can thus be tested using the proving unit, prior to testing a real live circuit.

To test the Line Tester the two probes are pushed against the Proving Unit which then produces a voltage.

This will be indicated by an indicator LED lighting up on the proving unit itself.

The Neon or Led indicator lamps of the Line Tester should also light up at the same time, to indicate the voltage being supplied.

Tips when changing bearings on Induction Motors

Bearings on Rotor

The bearings on an induction motor, allow the ‘Rotor’ to rotate inside the ‘Stator’ which surrounds it.

Over time they can become worn, which may increase noise and vibration of the motor.

Bearings are not usually adjustable, so replacement is required.

 

Importance of  Bearing identification code facing outwards.

When refitting bearings to an induction motor you will notice that the bearing itself has a code written on the one side of it.

This code is the product identification code, and is what you need to quote in order to order the correct replacement bearing.

Once the correct replacement bearing has been obtained, and is ready for fitting, ensure the following.

Firstly, that the bearing identification code is facing away from the Stator, and outwards towards the end of the motor shaft.

This will help you in the future, if you ever have to replace the bearings again.

The reason for this is that you can just remove the end plate of the induction motor, and read the bearing code easily, provided it has been fitted with the code facing outwards.

If the bearing code was facing inwards, then it is harder to read the bearing code, and might mean that the motor shaft has to be disconnected from its mechanical load.

This adds to the motor downtime, and hence has financial and productivity implications.

 

Ways to remove bearings from induction motor shaft.

The ideal way to remove an old bearing from the induction motor rotor shaft is to use a bearing puller tool.

Removal is then just a matter of fitting, the tool into position, and winding in the screw thread in a clockwise direction.

As this happens, the bearing is slowly pulled up and off the shaft.

If however you don’t have a puller, other methods, such as  using a metal bar to leverage between the bearing and the end of the shaft can be tried.

However this is not the way I recommend, and you do it at you own risk of injury and damage to the motor shaft.

 

Methods for fitting a new induction motor bearing.

Ideally you will have a hydraulic bench press, that you can use to put massive pressure down onto the bearing to ‘press it’ onto the shaft, in the correct position.

When using such a press, a number of precautions should be observed.

Firstly, ensure that you are fully competent to use the hydraulic press. Even fairly cheap versions are capable of exerting many tons of pressure, which can be dangerous to human health.

Secondly, ensure that the tube or sleeve that you fit over the shaft of the motor is only just wide enough.

The reason for this is that a wide metal tube (or sleeve) put over the motor shaft in order to push against the bearing, can damage it.

This is because too wide a tube will make contact with the plastic middle of the bearing, or the outer metal edge.

Both of these two scenarios are bad, because pressure applied to anywhere but the centre metal part of the bearing, will cause damage.

This damage can result in the replacement bearing being ruined, which defeats the object of replacing it.

Using a hydraulic press is the method that we would recommend, however this option is sometimes not available.

In particular to engineers working at sea in a marine environment, such as a cargo ship.

If you find yourself in this situation, then there are other ways to re-fit a replacement bearing to an induction motor.

One method is to take advantage of the fact that metals contract and expand due to cold and heat.

This method involves carefully wrapping up the Stator part of the induction motor in a polythene bag, and putting it in the freezer overnight.

This will very slightly shrink the size diameter of the bearing shaft.

The second part to the operation involves gently heating up a pan of engine oil, so that it is warm.

Obviously extreme care needs to be taken, so that either a fire is not caused by the oil igniting, or the engineer receiving burns while trying to handle the hot bearing.

Once the bearing is warm, the Stator can be removed from the freezer, and the warm oiled bearing should slip fairly easily onto the shaft.

The oil can then be wiped off the bearing with a non fluffy cloth, and motor reassembly can begin.

 

 

 

Featured

Electric Morris Minor

This blog post is about my design suggestions for an electric Morris Minor.

There have already been some prototype electric Morris Minor conversions already, which I will discuss.

In addition I have designed alternative ways to successfully convert classic cars such as the Morris Minor.

History & background

The Morris Minor is a British car designed by Sir Alec Issigonis, that was launched in 1948.

The Morris Minor originally was produced with an 918cc Side valve Petrol engine, but this was replaced in the early 1950s by an Overhead Valve (OHV) engine.

The OHV engine was improved and its size increased during the remainder of its production. and the later models were 1098cc in cubic capacity size.

The standard Morris Minor had the engine connected to a four speed longitudinal mounted gearbox, attached at the back of the engine.

The gearbox output is connected to a long single drive shaft, which runs underneath the car.

The drive shaft connects the gearbox to the rear axle.

The rear axle incorporates a ‘differential’ which fixes the speed ratio, between the rotational speed of the drive shaft, and the rotational speed of the road wheels.

Therefore as the engine power is transferred via the gearbox and drive shaft, to the rear axle, it is a rear wheel drive car.

Any design for an electric Morris Minor, will probably stick with the rear wheel drive configuration.

The reason for keeping the electric Morris Minor as Rear Wheel Drive, or RHD for short, is engineering design simplicity.

The front suspension on a Morris Minor was advanced for a British car of its time (1948).

The front suspension used torsion bars, as the springs, and featured ‘rack and pinion’ suspension, that is still used in modern cars.

The shock absorbers are different to the type used in modern cars, and are known as ‘lever arm shock absorbers’.

To convert an electric Morris Minor into powering the front wheels, known as front wheel drive, would require major suspension modifications (unless hub motors were used).

This is because the original Morris Minor steering and front suspension system, would need a lot of component changes.

Of course its possible to make a front wheel drive Morris Minor, but more expensive, and also changes the cars handling characteristics.

If however you are hell bent on a front wheel drive electric Morris Minor then its possible.

My solution would be to use hub integrated motors.

Hub integrated motors consist of an individual electric motor powering each driving wheel.

For instance to create a front wheel drive Morris Minor, you would have two motors driving each of the two front wheels.

If you wanted to use hub motors, but to keep the traditional Morris Minor rear wheel drive configuration, you would fit the motors to the two rear wheels.

So let’s decide to stick to the original rear wheel drive layout for our electric Morris Minor.

There are four ways that you could configure the electric motor layout. This also applies to many other classic cars, which share the same basic layout.

Firstly, the original internal combustion engine can be removed, whilst leaving the Morris Minor gearbox, driveshaft and rear axle (Inc differential) in place.

An electric motor is then attached to the original Morris Minor gearbox.

Some electric motor conversions that use this layout configuration, are clutch less in design. The torque & high rev range of many electric motors mean that the car can be driven in the same gear for most of the time.

Other electric car conversion designs still incorporate a conventional clutch.

The advantages of retaining a clutch are better motor speed control, and more importantly more retention of the original Classic Car experience.

A second option for mounting the electric motor in your Morris Minor, would be by removing the gearbox and either mounting the electric motor at the front end of the drive shaft, and directly attached to its front end.

Or alternatively the drive shaft could be removed, and the motor mounted directly to the rear axle differential input shaft.

This second method of attaching the electric motor directly to the rear axle differential connection, has advantages and disadvantages.

The advantage is a saving of weight, by removing the drive shaft which runs underneath the car, from front to back.

Less weight is a good thing for performance of your electric car.

The disadvantage is that it makes it a bit harder to mount, than if you mounted the electric motor at the front end, and retained the driveshaft.

It is harder to mount, because you need to create a mounting cradle which attaches to the rear axle, and supports the weight of the electric motor.

Morris Minor Hybrid


You may well of heard of Hybrid cars.

If not, then let me explain what they are.

A hybrid car is a car that uses a combination of combustible fuel, such as petrol or diesel, and electric power.

A hybrid car might drive the wheels using an electric motor at low town speeds, and petrol at higher speeds.

Alternatively, the petrol (or diesel) motor could be used, if the battery was low on charge.

The use of electric motors at low speeds around towns, has obvious environmental advantages.

However you might also still want a traditional petrol motor for long distance trips.

My design for a Morris Minor Hybrid, keeps the petrol engine, whilst also adding electric front wheel drive.

The rear wheels continue to be driven by the Morris Minors petrol motor.

Whilst the front wheels are driven by ‘in-hub’ electric motors.

A simple solution would be to have a manual switch, to be able to select the drive system.

Alternatively an automatic electrically controlled system could be used.

I am currently considering the design for an automatic system, and will provide further details in the future.

Gearbox Considerations

If you want design simplicity for your electric Morris, then keep the original gearbox.

The electric motor is simply attached to the gearbox, in place of the original petrol motor.

This is done via a special adapter plate, and a coupler.

The potential problem with using the original gearbox is excess motor torque.

Vehicle Electric Motors produce a lot of torque at low RPM (Revolution Per Minute).

The standard Morris Minor gearbox was designed to handle a maximum engine torque of 60 lb/ft (81 N·m) at 2,500 rpm.

The above torque figure is for the most powerful Morris Minor, built from 1962 onwards.

The gearbox was upgraded in 1962, along with the engine size (to 1098cc from 948cc), and gained Baulk-Ring-Synchromesh .

To ensure that you do not suffer premature gearbox failure, it is important that you consult electric motor manufacturers datasheets.

For an ordinary road going car, this should not be an issue, if precautions are taken to select a suitable motor.

For those looking to upgrade their Morris Minors performance, then this is definitely a consideration.

The characteristics of electric motors is instant maximum torque at very low rpm.

This sudden surge of torque needs to be considered, as it could damage the standard minor gearbox in a relatively short time.

The morris minor has been converted and upgraded for many years by enthusiasts, including the gearbox.

One popular conversion is to fit the Ford Sierra gearbox.

The Ford gearbox offers two advantages.

The first advantage, is that the Sierra gearbox gives you five forward gears, compared with the minors original four.

The second advantage of changing the gearbox to the Ford unit, is strength. The gearbox is stronger, and can handle more power.

Featured

Zigbee Technical Characteristics

Characteristics Overview

Zigbee characteristics make it suitable for short range wireless communications.

It is based on the IEEE 802.15.4-specification, created by the Institute of Electrical and Electronics Engineers (IEEE).

The technology is used to create personal area networks, also known as PAN(s).

PAN’s are created using low-power digital radio tranceivers, using Zigbee technology.

 PAN’s are used in applications including home automation, data collection, and medical devices.

Zigbee is designed to be used in small scale projects requiring wireless connection.

Characteristics of the technology is low-power consumption and RF transmit power, low data transmission rate, and short communication range.

  • Developed by Zigbee Alliance
  • IEEE 802.15.4 based specification
  • High level communication protocols
  • Used to create Personal Area Networks (PAN)
  • Uses small low power digital radios
  • Typically used for home automation, medical device data collection, other projects requiring low power & low bandwidth
  • Conceived in 1995, standardised in 2003, revised in 2006

Features of Zigbee

  • Low power
  • Low data rate
  • Close proximity data communications
  • Wireless ‘ad hoc’ network (WANET), which is a decentralised type of wireless network.

Zigbee Advantages (compared with other WPANS, such as Bluetooth & WIFI)

  • Simpler
  • Less expenditure

Applications (typical uses)

  • Wireless light switches
  • Home energy monitors
  • Traffic management systems
  • Other consumer & industrial equipment, requiring short communication range & low wireless data transmission rate
Typical  Performance
  • 10 – 100 meters range (per device), based on line of sight
  • Range dependent on both power output & environmental characteristics
  • Long distance communication possible by passing data through a ‘mesh network’, which allows the data to transfer through ‘intermediate’ devices between zigbee nodes
  • Long battery life, due to low power consumption
  • Secure communication using 128 bit symmetric encryption keys
  • 250 kbit/s, which is suited to intermittent data transmissions, such as from a sensor or other input device.

Wireless Data Overview

What is 802.15.4 and Zigbee?

IEEE 802.15.4 is a technical standard which defines the operation of low-rate wireless personal area networks (LR-WPANs).

It specifies the physical layer and media access control for LR-WPANs, and is maintained by the IEEE 802.15 working group, which defined the standard back in 2003.

WLAN

WLAN is short for Wireless Local Area Network.

WPAN

WPAN is short for Wireless Personal Area Network.

Zigbee versus Bluetooth & WIFI

For the Internet of Things (IOT) & IIOT (Industrial Internet of Things) the choice of wireless technology, depends on application.

If large amounts of data need to be transmitted between the sensor, and the receiving end, then Wifi may provide the best solution.

An example of an application requiring high data rates is transmitting video images, such as those from a CCTV camera.

WIFI is ideally suited to such an application.

Where WIFI has disadvantages however, is in power consumption and maximum amount of user nodes.

The relatively high power consumption of WIFI, compared with Bluetooth (especially Bluetooth Low Energy), and Zigbee, has issues.

The main issue is that the technology is not well suited to battery powered operation.

If WIFI links are used for data transmission, from remotely located sensors, then regular battery changes are necessary.

Of course if a mains electrical supply is available, then this isn’t an issue.

Bluetooth offers better (lower) power consumption than WIFI, so is a better solution for battery powered equipment.

The disadvantage of Bluetooth is that only 7 connections can be made simultaneously.

The connection time to establish a new connection is also longer in both Bluetooth and WIFI, compared with Zigbee.

Zigbee offers very low power consumption (especially in sleep mode), making it suitable for remote sensors, with long battery lives.

Battery lives can be a few years!

Zigbee is best suited to applications that require small amounts of data to be transmitted at a time.

An example is medical data monitoring of patients, or wireless light switches (Home automation).

Coronavirus Worldwide Fast Response Detection Solution

Coronavirus pandemic detection could be improved using already existing tools at our disposal.

Nearly everyone in the developed world has a smartphone, or

Most smartphones use the Google Android system, which like its Apple competitor, has voice search capabilities.

Amazon and others also have their home smart speaker systems (Alexa).

Voice search is built in already, and is triggered by trigger words, such as ‘Hey Google’.

As most of the world already has voice search technology, it can be used to detect coronavirus.

What tech companies need to do, is modify the algorithm that detects existing trigger words.

The voice search system modification that I imagine, would detect peoples coughs.

Using AI, the system could ideally differentiate between normal coughs, and the sound of a potential Cough caused by Corona-virus.

Even if a quicker to develop and deploy system that detected all coughs, was used, it would still be useful data for tackling coronavirus.

The ‘cough data’ can be sent to local authorities and health responders, who would then know who is potentially at risk, or suffering illness.

This in my humble opinion is a better solution than the one that Israel has apparently introduced. My reason for saying this is because the system that countries such as Israel, USA, UK etc are considering using, identifies ‘historical’ links (via smartphone and internet data) between those diagnosed with coronovirus, and those they have been in contact with, in the past.

The weakness of that approach, is that some people will contract coronavirus, due to exposure to others, but only experience mild symptoms.

If the virus gets really bad, it may be necessary to allow those with the virus, but not experiencing illness, to carry on working in some industries.

By instead using voice search, authorities get up to date live data on who is ill and where.

The voice search coronavirus detection idea, would also provide data on people nearby, who may not own a mobile phone, as their cough would trigger smartphones nearby.

In developing countries, where smartphone ownership is not so widespread, the use of so called ‘smart speakers’, such as Amazons ‘Alexa’ system could solve this.

An Alexa type system, connected to high sensitivity microphones, and deployed in towns and villages, could give local & national authorities an idea of corona virus spread.

These are my thoughts / ideas to help our global response to Coronavirus.

This article originally was written on my linkedin profile: Here

Smart Wine Glass

I Need More Wine – Wireless Sensing Smart Wine Glass

Benefits of I need more wine:

  • Automatic monitoring of diners who need more drink, using smart wine glass technology
  • Notification of ‘idle’ glasses, that are ready for collection
  • Opportunity for happier customers
  • Opportunity for increased drink sales revenue
  • Save employee time, monitoring restaurant tables*

I need more wine, provides restaurant owners with a solution that not only saves you money, but also pleases customers.

For enquiries, contact the designer Craig Miles.

Twitter: @acraigmiles

Linkedin: https://www.linkedin.com/in/craig-miles/

Instagram: https://www.instagram.com/mrcraigmiles/

Bridge from Scotland to Northern Ireland Alternative Solution

Yesterday UK prime minister Boris Johnson re-announced his plans for a bridge linking Scotland to Northern Ireland.

Critics, including many leading engineers have suggested that the plan is impractical.

This is due to the depth of the water, and also the fact that the seabed contains huge amounts of dumped World War2 explosives.

A better alternative

So is there a better way to link Scotland with Northern Ireland?

I believe there is.

My design will allow cargo transport between Scotland and Northern Ireland, using guided drone trucks.

The drone trucks will hover above the sea.

The drone trucks will be guided by radio signals, to keep them on track.

 

More details to follow soon!

 

 

Drone Trucks The Future Road Ahead

Why have Potholes!

This blog post is about my ideas for the future road ahead.

Roads as we know them today, have been around for millennia, in one shape or form.

Although they are probably better than they have ever been, from a historical perspective, they are not perfect.

Heavy traffic levels, combined with restricted road maintenance budgets in many countries, have led to crumbling road surfaces.

Flying Trucks!

If trucks could fly then you solve the problem of road wear.

Of course trucks don’t fly, well at least not yet they don’t.

Drone Trucks!

Drone trucks could replace conventional road trucks, and save road wear.

Road wear would be eliminated, because the drone trucks would hover off the ground.

The drone trucks would be guided using radio waves, guided by radio beacons and GPS.

Drone Truck Safety.

Trucks are obviously heavy, so having one hovering above other road users could be potentially dangerous.

Power Issues

The issue with conventional drones is that they use propellers to make them fly.

The size of propellers needed to lift the drone truck, and its cargo, would need to be large.

Large propellers need large electric motors to power them, which require lots of power.

An alternative hybrid solution involving an airship combined with a traditional drone, might be the solution.

The drone truck I have in mind (and have designed in principle) would be capable of carrying heavy loads for long distances.

More Efficiency

The drone truck would be guided by wireless beacons and GPS tracking.

The drone truck would not require a driver, which would save money for the haulage operator.

Not having a driver would also eliminate the need for drivers to stop for statutory rest breaks.

This improves operational efficiency of the vehicle, and greater return on investment.

 

Reimagining The Road Of The Future

Reimagining the road of the future, will improve on current road space efficiency.

The M1 motorway in the Uk now carries ten times the daily traffic, that it was originally designed for.

The M1is Britain’s oldest motorway, and was opened in 1959.

For those unfamiliar with the term ‘motorway’, it is similar to the autobahn, autostrada, highway etc in other countries.

The motorway is a multi lane, high speed road, with barriers separating the two opposing directions.

The Problem with Motorways Today

In many countries, such as the Uk, the popularity of the car as a mode of transport, has put pressure demands on the motorway networks.

The are are three ways to tackle the increased congestion:

  1. Restrict the public’s access to cars and other non business vehicles.
  2. Build more physical road infrastructure.
  3. Make better use of existing road ‘real estate’, though new technologies.

This article is mainly focused on the third option, of making better use of what we already have built.

Firstly however, lets look at what is wrong with option 1, restricting public access to using private not business vehicles on the road.

Restricting the use of motor vehicles by the general public would be a controversial move.

Some environmental groups, such as Greenpeace & Extinction Rebellion might welcome it.

However the majority of the public would become angered.

An annoyed public poses two problems for a countries leaders.

Firstly, some communities have poor transport alternatives to the private motor vehicle.

This could be due to the lack of bus and train services.

This could prevent some people being able to continue in their jobs, and therefore pay tax to the state.

The second issue, is related to politics.

Introducing a policy that restricts potential voters access to using their cars, could be a foolish move politically.

This is especially true near election time.

If governments tried to restrict car use, then how would they achieve their objective.

Some countries like Greece and India, have tried to control pollution on bad air quality days, by vehicle registration number.

For example only cars with either an odd, or alternatively an even number at the start of their vehicle registration plate, can drive on that particular day.

This approach potentially causes problems for people getting to work.

Though the approach potentially encourages car sharing with colleagues and neighbours.

Another approach to reducing car transport is to only allow ‘Green’ vehicles on particular roads.

Central areas of cities such as London, now have low emission zones, where only green vehicles, such as electric, are allowed.

Some cities alternatively do allow older more polluting vehicles on certain roads, but with a high ‘congestion charge’.

The congestion charge makes it expensive for more polluting vehicles to use the roads.

This unfortunately is an unintended form of discrimination against mainly poorer people, with older cars.

Basically its mainly the poorer, that end up paying more to drive.

Option two from my list is to build more physical road infrastructure.

First lets look at the advantages of building more roads:

Building more roads creates construction jobs, and the workers pay taxes, and buy things from businesses, such as televisions and mobile (cell) phones.

Initially cars can flow easier, as there are more roads. Though as the M25 around London proves, they soon become very popular and congested.

The sensible solution therefore would be option three, namely to make better use of existing infrastructure.

I have imagined a few improvements that can be made to the existing road system.

One imagination, is an integrated system between road and rail.

The system would use an app on your smart phone, to enter your destination.

The app would work in a similar way to Google directions at present.

But rather than the app giving you directions via smartphone voice and maps, it would tell your driverless car where to go.

The driverless car would then take the shortest route to your destination.

The system is integrated with the railway system, and vehicles automatically drive on and off special ‘flatbed’ trains.

I have made a video on youtube, which further explains the concept.

This article will be expanded  and continued on a regular basis, as time permits. So keep coming back, or subscribe.

 

 

 

 

 

 

5G IOT Benefits For Society

Opportunities

5G IOT (Internet of Things) brings a number of benefits and new opportunities to the business world, allowing new business opportunities.

5G is the fifth generation of mobile phone technology, which originally started with the analogue TACS system, back in the 1980s.

Although data SIM cards for IOT applications are already available for use with 3G/4G, 5G is the first mobile (cell) phone technology specifically designed for use with IOT.

5G offers fast Gigabit data transfer rates, with very low latency.

The 5G network is also very reliable, with a dense number of local cells giving good redundancy, in case one cell should fail.

At least this is what is claimed, though of course history shows us that the mobile phone system can temporarily go down.

5G IOT is set to be a massive growth area, with estimates of 76 million 5G connections by 2025 (Source: ‘IOT Analytics’).

IOT Potential Uses

Robotics

5G allows the effective connection of Industrial robots.

When we think of robots, people imagine different things, but robotic machines range from static robots, such as those used in car production, to autonomous guided vehicles (AGVS).

Other applications include:-

Video Surveillance

Smart Intelligent Mobility

Smart Grid Automation

In Car Infotainment

Vehicle Telematics

The use cases above, will be expanded on when I get more free time.

So check back regularly.

 

Creating a World Farm

Future World Farm

Creating a world farm would have two main advantages.

The first advantage is economy of scale, and the second advantage is increased profit and revenue.

So first I will explain what I mean by a world farm. What I mean is using technology to manage areas of agricultural land, located in geographically disperate locations.

An example is having a wheat field in the UK, and another in Australia, managed through communications technology.

Whatever your views on world politics, globalisation is here to stay, an will likely increase due to technology.

Smart agriculture offers more efficient farming through the application of sensors and robotics.

The Internet of Things uses environmental sensors, to collect data, such as soil ‘ph’.

The data is transmitted wirelessly from the sensors, using LPWAN technologies such as LoraWAN or Sigfox.

At the receiving end of the data transmission, a device called a Gateway, receives the wirelessly transmitted data, and puts it onto the Internet.

Once the data from the remote sensors is in the internet cloud, analysis and automated decisions can be made.

Robotics also now being developed to replace humans in agricultural food production.

An example of a farming process currently often done by humans, is picking cabbages.

Picking cabbages is labor intensive, and therefore is significant in the costs of production for the farmer.

A robotic solution would have a high initial outlay cost, but may be cheaper over a number of years of expected operational life.

As happens today with some agricultural processes, such as ploughing, there is a new potential business opportunity for agricultural contractors. In the future contractors may well bring a robot to a farm, rather than a tractor or plough!

Of course with the introduction of driverless vehicles, in the future the Plough may bring itself to the farm!

So back to creating a world farm, which is the focus of this blog post after all.

Satellite IOT

Just to recap for non technical readers, what IOT actually means.

IOT is short for the ‘Internet of Things’.

IOT is a general term that covers any device or machine connected to the Internet.

Therefore IOT devices encompass both devices used by the public, such as sensors on mobile phones, and also Industrial IOT (IIOT).

IOT devices use a variety of wireless connection technologies, but they work at a terrestrial level.

What I mean by terrestrial, is that the radio signals are all transmitted from the ground.

The radio frequencies used in IOT devices vary, but are at radio frequencies above 30 Mhz (MegaHertz).

In normal atmospheric conditions, radio transmissions at frequencies above 30Mhz travel in ‘line of sight’.

What this means is that they don’t bounce off the ground, or atmospheric layers, as is possible at frequencies below 30 Mhz (known as ‘HF’, or High Frequency).

Using HF frequencies long transmission distances of thousands of miles are possible, due to the signals ‘hopping’ and being reflected by various ground and atmospheric layers (intend to write a separate blog post on this).

IOT devices don’t use HF frequencies below 30 Mhz, for a few reasons, one being that a very long antenna is needed at lower frequencies. This makes using it impractical for wireless field sensors.

Therefore we are dealing with radio waves above 30 Mhz, traveling in basically straight lines.

Now consider the shape of the Earth, which unless you are a ‘flat earther’, is round.

As the distance between the wirelessly connected sensor and the receiver increases, the curvature of the earth can become a factor.

In radio communications, such as the mobile (cell) phone system, antennas for the cell base stations are mounted on towers.

The reason in case you haven’t already guessed, is to help overcome the earths curvature.

Having a high antenna allows the signals to travel further, without obstruction.

Now in the case of agricultural crop monitoring, the sensors might be in the ground. Whilst it may be possible to mount the sensor antenna higher than the sensor itself, it will still likely be near ground level.

Now of course in theory you could attach a long antenna coaxial cable, between the sensor unit and the antenna.

This however would reduce the power of the signal being transmitted, due to increased signal attenuation caused by the long antenna cable.

To be continued soon…….

 

 

 

 

 

 

 

 

Induction Motor Starters Types

Induction motors are a common type of ac motor, used in both industry and on board ships, with a number of induction motor starters.

The type of induction motor starters that are chosen, depend on a number of factors.

Direct On Line Starters (D.O.L)

Direct on line, or D.O.L for short, are a simple way to switch on smaller ac Induction Motors.

DOL is used to start smaller induction motors, which have a current rating of up to 10 amps.

In a DOL starter system, as Contactor is used to switch on the induction motor.

The Contactor is similar to a large electrical relay, and its function is to switch on and off, the large currents drawn by the induction motor.

When the operator presses the start button on the control panel, a voltage is supplied to an insulated coil inside the Contactor.

The coil works as an electro-magnet, and exerts a magnetic pull on the switch contacts also inside the Contactor casing.

The magnetic field causes the switch contacts to close, therefore allowing current to flow into the induction motor, and starts it.

The switch on the control panel that is used to start the motor, only works when it is pushed in. As soon as the operator releases their finger, the power ceases.

This is obviously not convenient to have to hold the button in, therefore an extra ‘auxiliary contact’ is included in the Contactor, which is wired to ‘lock’ the supply current on, even once the button is released.

The Contactor will remain locked on, allowing the induction motor to run, until a separate off button is pressed.

The off button breaks the link to the auxiliary contact, which releases the Contactor, and cuts the electrical supply to the motor.

In a three-phase DOL starter system, a single phase supply is taken from one of the input phases, and fed into the primary side of a single phase step down transformer.

The output from the transformer is used to supply the coil inside the Contactor, which closes the contacts, and makes the motor start.

Star-Delta Starters

Star-Delta Starters, which the Americans call Wye-Delta Starters, are used for starting larger induction motors.

What I mean by larger induction motors, are motors that are draw over 10 Amps of current at full load.

Induction motors have a metal plate on them which specifies the maximum current drawn by the motor.

This will be described as FLC, which is short for Full Load Current.

The reason we don’t use DOL starters for larger ac induction motors, is something called ‘inrush current’.

When you first start an induction motor, the current drawn by the motor is a number of times higher than the motors steady operating current.

Its similar to when you accelerate a car from standstill, in that more energy is used to get it going, than when its cruising at desired operating speed.

The problem with having a high initial current on motor startup, is that you need bigger capacity cables & contactor to cope with the large current.

Needing larger cables increases costs, as a motor with a FLC of 20 Amps, might have an ‘Inrush’ current of five or more times the FLC.

20 Amps x 5 = 100 Amps!

Star-Delta starters reduce the initial starting (inrush) current by starting the motor in a ‘Star’ wiring configuration.

A three phase induction motor has three sets of coils in its Stator windings. This results in six connections coming out of the Stator (two ends of each of the three coils).

To be continued…..

 

 

 

How Marine Generator Works & Fails

How a marine generator works is something I taught to students at South Shields Marine School many times.

The photo is of a marine generator from an old ship.

The end has been removed to allow easy access, and for demonstration and test purposes.

The marine generator in the photo was original attached to the ‘Prime Mover’ (ships engine) by a coupling at the other side of the generator.

The coupling is connected to a shaft which goes into the generator casing.

Inside the generator casing the shaft is connected to a Rotor.

Attached to the Rotor are electromagnetic Poles.

The Poles are supplied with DC (Direct Current) electricity, and act as electro-magnets.

Theory states that electricity can be generated by moving a magnet through a coil of wire.

This is why the Poles attached to the rotor, are turned into electro magnets.

As the rotor, and hence the poles rotate, they are surrounded by large coils of wire.

The large coils of wire that surround the poles is called the Stator.

The Stator coil in a marine generator, consists of three sets of copper wire coils.

There are three sets because the generator is a three-phase generator.

The three coils are connected in a star configuration as shown on the screen.

 

Each of the phase connections, which I have labelled ‘phase 1’, ‘phase 2’, ‘phase 3’, are connected to the generator ‘Bus Bar’.

The Bus Bar is the output connection from the generator, which connects to the ships electrical system.

Generator Exciter

I mentioned earlier that the poles which are attached to the generators rotor, are supplied with DC (Direct Current).

The device that generates the DC voltage is called an Exciter.

The Exciter is attached to the same rotating shaft as the main generator (which is driven by the Prime Mover).

The difference with the Exciter compared with the main generator, is that the poles are fixed & do not rotate with the rotor.

Instead the rotor, which contains coils of wire, rotates between the poles.

Therefore like the main generator, the exciter produces electricity.

The poles in the Exciter differ slightly from those in the generator.

The difference is that they retain magnetism, even when the generator is not being used.

Without this residual magnetism, the generator would not be able to start.

This is because there would be no magnetic field for the coil of wire (in the stator) to move through.

Therefore no electricity generated.

Just like the main generator, the Exciter produces AC, or Alternating Current.

Therefore to produce the DC needed to supply the generator poles, the AC needs to be connected to DC.

This is done using a rectifier circuit, which is incorporated into the Exciter.

A rectifier circuit uses diodes to chop off half of the alternating current, so that only DC is produced at the rectifier circuits output.

 

This DC is then fed via wires, into the Poles of the main generator, creating magnetism in the Poles.

If we didn’t change the original AC produced by the Exciter, into DC, then there would not be a stable magnetic field produced in the generator Poles.

Fault Finding

If the generator has been idle for a period of time, and you try to start it, it may not work.

This is due to the loss of magnetism in the Exciter Poles.

The Poles are designed to maintain a residual magnetism, even when the generator is off.

This magnetism can however ‘leak away’.

This happens over a period of time, due to the fact that the Exciter is encased in a metal casing, which can absorb the magnetism.

If the generator will not start, and it has not been used for a while, this could be the generator starting problem.

The solution is to put the lost magnetism, back into the Exciter Poles.

This is done by what is known as ‘field flashing’.

You can field flash the Exciter Poles by attaching a battery to the Poles wiring connections, for a short period of time.

This will re-magnetise the Poles, and hopefully allow the generator to start.

Generator Maintenance Testing

A marine generator is both mechanical & electrical.

Mechanical Checks

Include bearing lubrication, and wear measurements, using Feeler Guages.

Electrical checks are mainly focused on the continuity & Insulation resistance values of the generator Stator.

Continuity Checks

As previously stated the three coil windings in a marine generator Stator are connected at one end, to form a Star connection.

 

Continuity checks test that the coils are not broken, and have a low electrical resistance, from one end of the coil to the other end.

The only slight problem you may face is that the ‘Star Point’, which is the point at which the three coils are connected together, is not accessible, on your generator.

This is because the Star Point is often buried in the Stator windings.

If this is the case,  what you need to do is measure the continuity through two sets of windings at a time.

This is done via the three Bus Bars, using a low range Ohmmeter.

The resistance should be low, and very similar, between the different coil combinations tested.

Insulation Resistance Checks

The three separate coils of wire in the three-phase generator Stator should have a high resistance between them.

If there was no or little resistance between the coils, then a short circuit would occur, and the generator would not run.

An insulation resistance meter tests the windings resistance  under realistic working conditions, by supplying a high voltage to the coils.

For a 440 Volt marine generator, you would normally set the insulation meter to double its normal operating voltage.

Insulation testers typically offer 250, 500 & 1000 Volts ranges.

Therefore for a 440 Volt marine generator you would test at 1000 Volts.

If you are regularly testing, you may wish to reduce the meter setting to 500 Volts, so not to unduly put stress on the Stator winding’s.

The minimum insulation resistance figure under SOLAS regulations is 0.5 Mega Ohms.

Though really you would not want to see anything below 2 Mega Ohms in a healthy marine generator Stator.

 

 

Earthing Systems On Ships Insulated Neutral Versus Land

Insulated Neutral on Ships

Contents:

The difference between land based power delivery and the earthing system on ships (most, but not all).

  • Land based = Connected neutral & earth
  • Earthing systems on ships = Insulated neutral, not connected to ships hull

Land based connections

  • Main priority is maximum protection of people and livestock.
  • Neutral & earth connected together at local substation (step down transformer), and also where the cable enters the building.
Earthing systems on ships

Most ships have an ‘insulated neutral’  electrical system.

As the name suggests, the neutral wire is insulated from the ships hull, which is the closest thing to a land based earth aboard ship, at sea.

Insulated Neutral Practical Differences

On land, an earth fault would cause the Residual Current Device, or RCD,  to trip.

The system is designed for maximum protection of people & livestock.

At sea the main priority is safety of the ship.

If critical systems such as steering gear were the trip, due to a single fault, then it could potentially be catastrophic.

Therefore on ships a single earth leakage fault between the power and the ships hull, can happen without tripping the circuit.

What happens instead is that an alarm will be triggered on the ships earth fault monitor panel.

It is important that a single earth fault in an insulated neutral system is repaired as soon as possible.

This is because if a second fault should occur, then the circuit will trip, which could out the ship at risk.