RFID in UK ?

[SmartyPants]

Hi.

I'm interested in setting up some RFID tags for vehicle and person proximity sensing. I've noticed on here that the only two suppliers of equipment to be in the US. Any reasonably priced stuff for us in the UK?

Thanks

[Pete]

Here continue to utilize the old "cheaper RFID" tags in the automobiles powered by the car battery. I only use these for the automobiles and they work fine.

Person proximity sensors do work except that I never use them. Prices are a bit higher now than a few years back. The prices are about double or more today than a few years back.

[SmartyPants]

Here continue to utilize the old "cheaper RFID" tags in the automobiles powered by the car battery.

Thanks Pete. Can you sbe specific on the transmitters and receivers you are using?

Thanks

[Pete]

Over the years have collected many / most of the ananiahelectronics devices and they all worked fine for me.

Primarily utilize:

1 - RF8315R Active RFID Receiver, Serial Interface
2 - RF40315T-x 40 Meters Long Range Active RFID Transmitter - used in automobiles connected via 12VDC.

hxxps://www.ananiahelectronics.com/

CheaperRFID sold these in plastic cases many years ago.

Mostly utilized to announce arrival/departing automobiles.

Testing a wireless modem connectivity to the reciever these days. The wireless modem has a range of 8Km for detached buildings.

They are way more expensive than they were many years ago and you can probably brew up a similiar device for much less.

IE: say a Tasmota / Espurna 12 VDC wifi / 433Mhz device. (not sure on the 12VDC draw though).

[Michael McSharry]

I am going to give a try at couple very low cost approaches. The simplest case is to use a encoding RF transmitter module that will transmit one of four encoding. These are similar to guts of the 4-button keyfobs. They sell for around $1 for TX/RX pair in China. Add an oscillator to the enable pin so only transmits every few seconds, minutes or whatever is desired to reduce energy use in battery application. There is a corresponding decoder receiver that can be interfaced to any microcontroller, but I suspect the receiver in the Sonoff RF will work so that makes for the easiest packaging.

The second approach is use small and very cheap 433 Mhz RF transmitters paired with ATTiny85 8 pin microcontroller. The ATTiny85 will provide the encoding desired for the RFID recognition. This is more flexible encoding, but does require the receiver to be interfaced to something other than a Sonoff RF. Never have worked with ATTiny so this will be a learning experience.

[Michael McSharry]

Progress report...



I order 433Mhz generic TX and RX modules from Amazon https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 at $1.30/pair and ATTINY85 board https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 at $2.20/board. I mounted the two back-to-back and wired the 5V, Gnd, and Data signals between the two on the transmitter. On the receiver, I connected it to GPIO14 of Wemos D1 mini which I already had, but can be obtained at Amazon https://www.amazon.com/IZOKEE-NodeMc...s%2C292&sr=1-3 for $3.60. This results in a total cost of $7.10 per set. Normally one would have a single receiver and multiple transmitters with each transmitter tag being $3.50. 17 centimeters of small gauge wire is needed for antenna on each RX an TX if your junk box does not already have 433MHz antenna.

Power for my testing came from the USB connector on the ATTiny85 that is paired with the TX module. The ATTiny consumes in the microamp range. I measured the transmitter at a average of about 0.5 watt when transmitting at 50% duty cycle. Note that datasheet for TX is 0.01 watt when transmitting so some discrepancy there, but my measuring technique was crude. Power is proportional to the duty cycle so it transmission is reduced to once per minute rather than 5 times/second the average current use should be about 0.3 milliamps at 5VDC. A CR2032 coin cell will provide about 200 milliamphours of service for a lifetime of about a month. These are all rough calculations, but provides insight that battery operations may not be practical.

The ATTiny85 was very easy to program following the tutorial at https://digistump.com/wiki/digispark...als/connecting. The sketch used is a knockoff of the ASK example in the RadioHead library at http://www.airspayce.com/mikem/ardui...oHead-1.92.zip. I elected to transmit a 4 character RFID to be similar to what was done with the CheaperRFID hardware.

On the receiver side the same ASK RadioHead example was used, but integrated into Tasmota firmware to provide a rich development environment including MQTT (or HTTP) reporting.

All was working well with TX and RX in the same room with presence reported when either of the two transmitters was provided power and absence reported for a TX that had power removed. When I tried to extend range the presence was no longer detected. I also tried to increase the transmitter power to 12VDC but did not obtain any better results. Using SDR I could see that the signal was very strong going from a off/quiescent state of -60db to 0 db during the transmission period. This was true also when the TX was 50 feet away. The datasheet for the 433MHz hardware http://www.mantech.co.za/Datasheets/...z_RF-TX&RX.pdf provides range of 20 to 200 meters depending upon voltage in the 3.5 to 12V span.

Next step is to use SDR tools to try to capture and decode the actual transmitted RF to try to understand when the receiver is not able to decode the RF when more than about 10 meters apart.

I was pleasantly surprised how easy it was use the ATTiny85. This is a nice device for applications that just need a simple digital (or analog) control. They come in 8 pin DIP package for $1'ish depending upon source.

I have dabbled in the past with SDR, but usually no more that assessing the RF frequency. Using it I determined that I had 315 MHz CheaperRFID hardware so not able to evaluate if this hardware could be interchanged with this more modern approach. I always wanted to look at doing digital decoding with it so this gives me the reason to learn and add to my toolbox. If I have success then I may be able to reverse-engineer the CheaperRFID encoding and replicate it.

[Pete]

Great news Michael!!

Here my CheaperRFID tags are mounted in the dome lights with a constant 12VDC power source from the automobiles.

The old receiver is mounted in the attic of the two story home. I only use it for presence and a bit of security.

Do you have antennas connected?

Full wave would be 27.25 inches, quarter wave would be 6.8 inches.

[Michael McSharry]

Do you have antennas connected?

Yes, I have tried the prebuilt from my junk box that is shown in the picture avove and made 1/4 wave with cat5 wire. Seeing a 60 db swing when it is transmitting indicates plenty of 433Mhz energy is present at the receiver location.

[Wadenut]

I am going to give a try at couple very low cost approaches. The simplest case is to use a encoding RF transmitter module that will transmit one of four encoding. These are similar to guts of the 4-button keyfobs. They sell for around $1 for TX/RX pair in China. Add an oscillator to the enable pin so only transmits every few seconds, minutes or whatever is desired to reduce energy use in battery application.

That's an excellent idea. It would work well with small X10 devices like the DS10, probably adapted to a motion sensor (MS14, MS16) and even some of the small remotes I have around here.

[Michael McSharry]

I had not thought of the X10 RF, but the concept should work with it as well with a range of 50 or 100 ft. I think it has the same problem as the CheaperRFID in that the technology is old and somewhat hard to acquire

[Michael McSharry]

I was successful in getting working configurations of cheap 433 MHz transmitters and receivers with range of up to 150 ft. Total cost around $5 excluding power source. I evaluated both 5V and 12V transmitter power and I was surprised that the range was not improved that much with the higher voltage, but it was somewhat more consistent at reception with the higher voltage. The approach using generic transmitter and receiver provided a better range than the approach using the RF from remote encoder/decoder, but at up to 50 ft the remotes also worked.

I am not confident that the next set of generic 433 RF parts will perform the same as t he set I was using. To get a working configuration with the generic components I needed to use a transmitter from one source and a receiver from another. The paired units from the same source did not work together. The paired units for remote encoder/decoder approach worked fine together.

On the Homeseer side nothing needed to change in the mcsMQTT plugin to support the Active RFID. mcsTasmota firmware was updated to provide the selection of the two types of Active RFID that were added. This firmware can run in any ESP8266-based product such as Sonoff, Wemos or NodeMCU.

The full writeup with construction details and analyses is in Section 15.16.2 of http://mcsSprinklers.com/mcsMQTT.pdf

[Pete]

Great news Michael!!!

Probably will install the RFID SonOff next to the GDO SonOff in the garage.

[Michael McSharry]

If you want me to program the ATTiny85 or Sonoff let me know. Nothing special about doing it, but for those who have never done it before it could be considered too big a hurdle.

[Pete]

Seeing the new tab for BLE in the updated mcsMQTT pllugin. Very nice. Currently have old tags mounted in the area of the dome light in the automobiles with a constant 12VDC.

Thinking you mentioned that the power draw is minimal eh?

I have not yet purchased what I need to do this.

[Michael McSharry]

Just a follow on the project where the receiving unit is the Sonoff RF Bridge that was updated with Tasmota firmware. https://github.com/arendst/Tasmota/w...-the-RF-Bridge For the transmit side it was the qaichip keyfob RF https://www.aliexpress.com/item/3299...12c44c4dwg3h1k
with a 5 second oscillator emulating the keyfob button push. Other transmitters likely will work too, but for this quick test I just did the first one that came out of the junk box.


The console from the Sonoff RF Bridge showed the MQTT traffic with the data pattern 800168 being transmitted. The out-of-range indication is detected from mcsMQTT timeout rigger on Topic SonoffRF and payload containing 800168

06:09:11 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:11","RfReceived":{"Sync":7640,"Low":270,"High":750,"Data":"800168","RfKey":"None"}}
06:09:17 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:17","RfReceived":{"Sync":7650,"Low":270,"High":740,"Data":"800168","RfKey":"None"}}
06:09:23 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:23","RfReceived":{"Sync":7650,"Low":250,"High":740,"Data":"800168","RfKey":"None"}}
06:09:27 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:27","RfReceived":{"Sync":7690,"Low":220,"High":690,"Data":"800168","RfKey":"None"}}
06:09:32 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:32","RfReceived":{"Sync":7650,"Low":240,"High":730,"Data":"800168","RfKey":"None"}}
06:09:42 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:42","RfReceived":{"Sync":7680,"Low":240,"High":690,"Data":"800168","RfKey":"None"}}
06:09:47 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:47","RfReceived":{"Sync":7660,"Low":240,"High":710,"Data":"800168","RfKey":"None"}}
06:09:52 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:52","RfReceived":{"Sync":7670,"Low":210,"High":700,"Data":"800168","RfKey":"None"}}
06:09:57 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:09:57","RfReceived":{"Sync":7710,"Low":250,"High":730,"Data":"800168","RfKey":"None"}}
06:10:08 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:10:08","RfReceived":{"Sync":7660,"Low":230,"High":710,"Data":"800168","RfKey":"None"}}
06:10:13 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:10:13","RfReceived":{"Sync":7670,"Low":230,"High":700,"Data":"800168","RfKey":"None"}}
06:10:17 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:10:17","RfReceived":{"Sync":7650,"Low":190,"High":710,"Data":"800168","RfKey":"None"}}
06:10:22 MQT: SonoffRF/RESULT = {"Time":"2020-03-01T06:10:22","RfReceived":{"Sync":7690,"Low":220,"High":700,"Data":"800168","RfKey":"None"}}

Since the Sonoff RF Bridge has multiple application it may be more attractive than a dedicated receiver such as was done in the original evaluation.

Note this same approach of using Sonoff RF Bridge as the receiver will likely work with the CheaperRFID transmitters that were common a decade ago if one has the 433MHZ version. In my case I have the 315MHZ so was not able to confirm.