This is firmware for a Digispark (or clone) ATTiny85 based board to decode 433MHz transmissions from a Digoo DG-R8H wireless temperature/humidity weather station monitor and output them over a transmit only serial connection. Additionally it will do a periodic (once a minute) poll of an attached DS18B20 1-Wire temperature sensor and output its details. The intended use is to provide reception of remote temperature sensors (the DG-R8Hs) as well as a local temperature sensor (the DS18B20).
Although the Digispark can drive USB with the V-USB software implementation the timing constraints make it difficult to reliably detect and parse the 433MHz transmissions. Using a software driven TX only UART pin allows priority to be given to the decoding on received signals. Connection to a computer can then be via a cheap TTL USB serial dongle - testing has been performed using a CH340G based device which cost 50p.
Both the 433MHz receiver and the 1-wire sensor are optional, allowing the same firmware to be used on a device that only has one of these connected without modification.
The following connections are used on the Digispark in addition to GND/5V:
- PB0 - 1-Wire connection
- PB1 - TX serial out (230400, 8N1)
- PB2 - 433MHz receiver in
This project is licensed under the GPL 3+ license, see COPYING for details.
Code is available on GitHub.