Using the smallest moteino (w LORA?) as a small beacon for bird tracking

[Dmitry_Kishkinev]

Dear Forum participants

I am a bird biologist based in Bangor University, UK. I am interested in using the smallest weight and footprint moteino board for long-distance tracking of birds. Basically I'd like to deploy a moteino pcb with small battery and antenna on the back of birds with the hope it will be detected far away by third party gateway. My idea is to

1) find the smallest and lightest moteino (probably with LORA bc I need large gateway network not provied by myself) with very low power consumption 3.7v (ideally powered by coin batteries like Renata CR1025 or 1225 or small Lipo batteries 75 - 100 mah)

2) program this moteino to send very infrequent and unique ID code (maybe 1-2 times a day at a particular time) with the hope that, once deployed on the back of a bird, this signal will be received by the wide network of any third party LORA gateways (maybe LORA Alliance) or any other compatible with this device providers within UK and/or in continental Europe

Could you advice which model of moteino will be most suitable for me? And what third party LORA gateways providers could relay to me data on detection of such devices in the UK or in Europe?

Many thanks in advance

Dr Dmitry Kishkinev
Research Fellow
Bangor University, UK

[Felix]

Dear Dmitry,
Based on your description, it sounds to me like you would need a custom solution optimized for weight, but I would like to ask if there is any weight limit you are targeting?
Using a coin cell to transmit at 20dBm (the max TX power of RFM95/96) is problematic. Maybe going with a tiny Lithium LiPo cell instead will be acceptable if the size/weight are comparable. There are perhaps other coin cells with different chemistry that could sustain the needed transmit currents.

Anyway it's possible to make a custom solution. Here's something I made for a customer who needed a very small Moteino, optimized for low power:


For prototyping you could start with the Moteino (8Mhz) variant which has no LDO and is thus optimized for even lower power. But the gains might be offset by the large transmit currents you will need at greater distances.

Maybe you can use the LoRaWAN network, but my knowledge on that is limited, hopefully others can share more about that. I am sure there are other internet resources on LoRaWAN.

[Dmitry_Kishkinev]

Hi Felix

Thanks for the first tips.

Re weight requirements: at this stage any smallest device will find its birds' species but the smaller the better. If it is 10 g total weight then I will need 10 g / 5 * 100 = 500 g + bird species etc.

Small lipo battery with high c (peak current) rating is OK with me. Ideally if lipo 75-120 mah will provide weeks and months of lifespan with just handful transmissions a day (1-2 pulses a day at least).

Regarding gateways for moteino. Am I right that it is only local private gateways that people connect their moteino projects to? Put in different words, my 8 MHz moteino board will not be received by large third party gateways across Europe or UK, only locally by my gateways?

[HeneryH]

On the security question you raise...  I know there is a security token coded into the sender and receiver sketches so that only your devices communicate with each other.

But I am not sure if the wireless transmissions are actually encrypted.  I doubt it but others may have a better answer.

[Felix]

The Moteinos come with RFM69 or RFM95/96 transceivers, based on Semtech chips.
Then you have to decide what library or protocol to use with them. There is the LowPowerLab RFM69 library, with a bunch of examples to get you going - this is a custom protocol based on what the transceivers offer - the easy packet mode. The RFM69 (SX1231h) also offers hardware AES128 encryption, not a very strong encryption but enough to keep someone busy for a while if they were to really try hard.

The LoRa transceivers (SX1276) does not have hardware encryption. There are many libraries for use with these, one that's popular is the RadioHead library.

FWIW you can always encrypt in software with whatever algorithms you want.

To read your bird's sensor data on public networks, they would need to support these radios - sounds like LoRaWAN is the way to go here - and you'd have to use their library or a compatible library that supports their protocols.