ESP32 beacon scanner

[kideon]

[Michael McSharry]

I am playing with ESP32 now, but I am not seeing how BLE is much different than RFID that was done several years ago. It seems the triangulation was problematic and installation dependent. Can you expand more on your concept? For short range the WiFi beacon would seem just as appropriate and the ESP8266 is a lower cost alternative.

My interest is more with LoRa which may have an application of home/away, but is not likely the technology for room to room identification.

[mrhappy]

If you are talking about beacons like the keychain BLE tags then when I looked at them they only go into very low power mode when paired with something (ie a phone). When they went into hunting mode (ie no connection) the power consumption shot up and made them unusable as they would not last more than a couple of days if they were out of BLE range.

My use case scenario would be that I would have the tag on my keys and then when I came into the house it would pair with a detector and trigger presence detection. Unfortunately with the fact that it was unpaired for eight hours a day (when I was at work) then the battery would not last to make it viable.

I don't know if things have changed or whether I was doing it wrong though!

[kideon]

I was envisioning something like Jon00's plugin but using BLE. Just scanning for UUID's in passive mode and unpaired. How would you implement Wifi?

For actual Beacon scanning I was just thinking of putting Eddystones or something along those lines in my vehicles and a reader in the garage.

[Michael McSharry]

For wifi, scatter ESP8266 devices at locations in the house that are essentially acting as AP where their job is to record and forward the MAC address and RSSI of whoever is sending the "Who's there" beacon used to find potential wifi networks. The RSSI from multiple receivers are triangulated to provide an assessment of the location of the roaming ESP8266 that is sending the beacon. My guess is that a database would be developed of location vs. RSSI stength pattern to isolate (triangulate) to a specific room. The MAC address would be used to isolate the specific "person" so it could be used for family-type application.

Most of normal Wifi energy is used following a connection in the process of establishing
TCP/IP protocol, the beacon does still need energy and battery life is a concern so something like a periodic interrupt, send beacon, shutdown/deep sleep would be done for the roaming device. Every second, minute, or whatever wakeup interval selected based upon the resolution vs. battery life tradeoff desired for a specific use case. The ESP32 has two processors and one is ultra low power to do basic functions and it may be a good choice for the roaming part of this architecture.

I have not tried this, but it seems similar to other applications that it should not be too difficult. The form factor for the roaming node would be a challenge for me. I am challenged with PCB fab and surface mount. Something like the Alexa buttons may be a candidate to hack, but have not looked at the details of the reverse engineering that has been published for these devices.

[Eman]

I am playing with ESP32 now, but I am not seeing how BLE is much different than RFID that was done several years ago. It seems the triangulation was problematic and installation dependent. Can you expand more on your concept? For short range the WiFi beacon would seem just as appropriate and the ESP8266 is a lower cost alternative.

My interest is more with LoRa which may have an application of home/away, but is not likely the technology for room to room identification.

Hi Michael,
Am just probing! (Just because the future is IoT!)
Now that you have mentioned LoRa, I have been digging quite deep and found some quite interesting topics : https://docs.mbed.com/docs/lora-with...intro-to-lora/

And : https://www.rs-online.com/designspar...-with-the-lopy

They seem good, you can cook up something which could benefit everyone but then again it could be a big ask

Just dilute for us to understand because this stuff is coming and it's the future!


Thanks.


Eman.

[Michael McSharry]

I am just getting started. I have a couple HELTEC ESP32 LoRa units that I suspect come with questionable RF as I can only get marginal communication with only inches separation. I do not have a spectrum analyzer, but I do observe the RF transmission with SDR. I have ordered a variety of antenna from AliExpress as I suspect the HELTEC ones are for a different frequency than the 868 and 915 the modules are supposed to be designed. It could be the are selling 433 MHz units with a marketing label of 868 and 915 to get sales in Europe and USA respectively. I also have some V2 of TTGO LoRa on order. I did not go down the path of Python units as my intent is to stay in the Tasmota environment once I get comfortable at the hardware layer.

LoRaWAN (TTN) is more developed in Europe than in USA, but as you stated this is the direction that has momentum. For raw HA the point to point over distance should be a good fit for LoRa. It is great that we live in a time of such cheap hardware to allow exploration at such a low cost. I am fortunate that China does make an attempt to provide some version of English to help a little with their hardware. The community of others with interest that share via internet is also a big benefit.

Whatever I do will be available to anyone who has interest. I have no commercial aspirations for it. My orientation is with the HS community that has shown much longevity and a supportive environment.

[Pete]

Googling on AliExpress see the two of the ones you are mentioning.

[ATTACH]67060[/ATTACH]

[ATTACH]67062[/ATTACH]

For tinkering with SDR here purchased a kit which included two antennas.

Currently tinkering with NOAA satellite reception at ~ 138 Mhz which works using these antennas inside of the house.

One is attached to an RPi and the other to a desktop. The RPi is in the attic. Been reading that you can utilize it as a remote reciever these days with the old SDR software.

[Michael McSharry]

These both look like Heltec units. I believe I did get mine from AliExpress. I have a 868/915 antenna from Amazon for quick delivery but in retrospect likely questionnable as it specs a general and not specific band. Yesterday I ordered others from AliExpress that showed test plots. Next month delivery.

The SDR I have looks like the same as what you show with UHF VHF and telescope. I can see the waveform change as I change the parameters to the Lora chip, but just cannot get a good RSSI at the receiver.

[Pete]

Yeah tinkering a couple of years back found best deal on antennas and connectors on Ebay over Amazon.

On Ebay delivery is around 1-2 weeks though versus Amazon Prime at two days.

Here are some antenna lengths..

433 1/4 wave = 164.7mm
433 1/2 wave = 329.4mm
433 full wave = 692.7mm

868 1/4 wave = 82.2mm
868 1/2 wave = 164.3mm
868 full wave = 345.5mm

915 1/4 wave = 77.9mm
915 1/2 wave = 155.9mm
915 full wave = 327.8mm

From this web site:

My Maker Addiction

[Eman]

These both look like Heltec units. I believe I did get mine from AliExpress. I have a 868/915 antenna from Amazon for quick delivery but in retrospect likely questionnable as it specs a general and not specific band. Yesterday I ordered others from AliExpress that showed test plots. Next month delivery.

The SDR I have looks like the same as what you show with UHF VHF and telescope. I can see the waveform change as I change the parameters to the Lora chip, but just cannot get a good RSSI at the receiver.

More on that also check this site out : https://pycom.io/product/lora-antenna-kit/



Eman.

[Michael McSharry]

Thanks for looking into other options. Going east is much more expensive than going west. While it looks like the one I got from Amazon, don't really know what is inside and same concern I have that one antenna to cover both bands which seems like it could work, but not optimized. Right now is it just a wait for the next ship from China for me.

[Timon]

Thought I'd do a quick ask here before starting a full thread on the subject.

Has anyone looked into a way to control a device, or signal HS, when a beacon comes within 18" or less. I've looked at RFID but for some reason no one has anything that's not in the hundreds of dollars range that can do 18" detects.

If anyone does I'll start a new thread to flesh out what I have in mind.

[Michael McSharry]

I believe the technology for this is what is used for badge readers or product tags to alarm as high value merchandise goes through the store exit door. Passive RFID. I have no specific implementation experience.

[Timon]

I believe the technology for this is what is used for badge readers or product tags to alarm as high value merchandise goes through the store exit door. Passive RFID. I have no specific implementation experience.

Yea, the tags for those are dirt cheep but the readers are REALLY expensive. I don't mind a more expensive tag but the reader has to be low cost. BluetoothLE may be the way. Oh well, I'll keep researching it.