Vermes
Advanced Member level 4
Presented here device is a magic knob using which you can control the volume/balance of an audio set. It can be an alternative for potentiometer that may not exactly meet user's needs.
The knob uses LSM330DLC as a position sensor. It is a gyroscope/accelerometer from ST. The accelerometer is used for waking the circuit and the gyroscope – as rotation sensor. The processor used is LPC1114. Transmission was implemented on CC2500 2,4GHz. The circuit has also a built-in charger with micro USB connector. Duration of work with used LiPo is about 3 weeks. The average time of charging is 30 minutes. The diameter of the PCB is 40mm.
The button is used to change the operating mode volume/balance, and the four LEDs indicate the current mode and the battery.
Although the volume adjustment in the original circuit was implemented by voltage regulation, the receiver used was the board of the transmitter (without the LSM330DLC) and filtered PWM output was connected instead of a potentiometer.
Link to original thread (useful attachment) - Magiczne pokrętło by piotr_go.
