This repository contains three parts:
- Schematics for setting up a connection between an HC-05 Bluetooth module, an Attiny85, and some transistors, in order to control a 5V power output.
- Arduino code that setups a bluetooth connection, and waits for serial input that controls the transistor output.
- Android code that implements a Tasker plugin which sends messages over Serial to a paired Bluetooth device.
The overall decisions and motivation are discussed in my blog post, but in case you might want to try it out for yourself, setup the Arduino example (make sure to change the name and paircode), and install the APK from Google Play.
Please note that for the Android code, Bluetooth must already be switched on, and the device to communicate with must already be paired.