The ATTNode (short for ATTiny Node) is a minimalistic node for the LoraWAN Network. It is based on the widely available ATTiny MCU from Atmel/Microchip and the HopeRF RFM95W LoRa Wireless Module. It can be used with a variety of sensors, the provided firmware does support the I²C-sensors SHT21 and BME280 for measuring climate data (Temperature/Humidity/Atmospheric Pressure) and is meant to be used with The Things Network as backend. The node can last for several months using only a CR2032 button cell sending values from the above mentioned sensors every 10 minutes.
Downloads for Gerber- and STL-files as well as the BoM and assembly hints can be found at the subsites for the corresponding ATTNode Version.
The current versions are ATTNode v2.0 and ATTNode v3.0
My tests with the v2 prototype PCBs where successfull, I did not find any functional issues with the boards, and only some minor cosmetic issues.
Documentation of the TinyLoRa v2 PCB is now available on this site . You can also find a ZIP with the Gerberfiles attached there, so you can order your own from the usual PCB prototyping companies.
After a long wait due to coronavirus outbreaks in China and resulting delays in the PCB production it is finally here, The first prototype of the TinyLoRa v2 Board:
The triple use footprint for u.fl, SMA and wire antenna seems to work as intended, and the rest of the board works as before. So all in all a sucessfull first prototype run.
Some more development on the TinyLoRa v2 board. I have modified the SMA connector footprint in such way, that it should now be possible to also use a U.FL Connector or use a Wire- or Coil Antenna instead of the SMA edgemount connector. With this change it should be possible to use all of the most common types of antennas with the node. I also did some more cleanup and finishing touches:
Here is a sneak peek at the next iteration of the TinyLoRa PCBs. I got it down to roughly half the size compared to the v1 board by making it a two sided board and putting the battery holder, which is by far the biggest component, onto the Backside. I also added the possibility to use a edge-mounted SMA connector for the antenna.
Because of the battery at the back the sensors don’t fit there anymore, so the GPIO-connector was flipped by 180° so the sensor now mounts over the front of the board. There are still some finishing touches to be done before I will put them into production, but it shouldn’t be to much work. As I don’t have any real boards yet here are some renders from KiCAD:
