A small Arduino code, that runs on an ESP8266 NodeMCU, which allows you to use an old PS2 mouse (with red laser) as a "power slider" to set a analog output (in the code I use a single LED) just passing over the hand (like Daniel-San, u know...) on the mouse sensor.
PS2 Mouse Library to interface the mouse: https://playground.arduino.cc/ComponentLib/Ps2mouse/ .
Color scheme used for wirings is PS_2.png