This program and project is based on the awesome work of Nathan Chantrell
- https://nathan.chantrell.net/tag/tinytx/
- https://github.com/nathanchantrell/TinyTX
and was deployed on the TinyTX4 board by meigrafd - https://github.com/meigrafd/TinyTX4
Also inspired by the emonTH project - https://github.com/openenergymonitor/emonTH
other references in the code
Features:
- Support of one or two DHT22 on one sender
- Send temp and humidity on different intervals than battery voltage
- Read battery and vcc voltage using higher precision interrupt method
- For battery connection I refered to:
- http://jeelabs.org/2013/05/16/measuring-the-battery-without-draining-it/index.html
- Only send when values have changed to save battery
- Random backoff timer when ACKs not received for each sender
- Send frames contain ack error count, and dht22 read error count
- Use a stripped down version of SoftwareSerial for read only to save a pin for RX and memory on the attiny
- Battery protection: shuts down when voltage is low to prevent leakage
The received bytes on serial on the raspberry pi are interpreted and pushed to OpenHab by a python programm located in "processing scripts"
- "tinySender" contains the sender arduino sketch
- "tinyReveiver" the receiver sketch
- "SendOnlySoftwareSerial" is a stripped down version of the original Arduino library
- See the JPG file for a glimpse of the TinyTX4 board with the battery level reading "circuit".