Unfortunately, no progress has been made with the hardware part of the project, namely the splitter and the mixer. Especially, the mixer evolved into an issue because the circuit built on the breadboard appears to be correct and even the project’s supervisor could find no error upon a brief inspection. However, despite all efforts, it does not seem to work properly and makes horrible noises when connected with its 9 Volts power supply… Nevertheless, as time pressure increased, it was decided to move forward and solder the mixer on a Veroboard instead of testing it on the breadboard – maybe it will start to work when all connection are firm. Consequently, two Veroboards were ordered.
In the meantime, it was decided to perform a major test of the left hand setup, involving all necessary components except said mixer. The idea was to have everything working so that when the mixer miraculously starts to functioning properly everything else already works and is ready to be tested in conjuncture with the mixer. The thorough the test of the left hand setup included several tasks.
Firstly, after some time off the headstock the ToF sensor was re-positioned again at the headstock of the test electric guitar and reconnect with the ESP32-LH (left hand setup). Then the ESP32-LH and the ESP32-CU (central unit) were re-paired using the ESP-NOW protocol. A change had to be made in the code of both ESP32s: so far, the ESP32-LH did all the processing of the ToF sensor values including computing the distances and the according frets, deciding if the Solo Mode has been activated or disactivated according to the fret threshold set and sending a corresponding message of 0 or 1 to the ESP32-CU. It was decided that the ESP32-LH should only be used to detect the frets and send the frets to the ESP32-CU who should then go on to decide over Solo Mode (dis-)activation based on fret threshold set and send 0 or 1. This comes with the advantage that if a flexible threshold can be set on the central hardware unit via a potentiometer, the ESP32-CU can receive this directly and the potentiometer values sending the fret threshold must not be send back to the ESP32-LH. This facilitates the code necessary because only a one-way communication is happening. After the relevant changes have been made in both codes, the setup was tested and it worked as expected. In the last step, the digipot was added. It was ordered to change between two resistance values depending on the status of the Solo Mode (ON = hand above 5th fret or OFF = hand below 5th fret). The resulting change in voltage was again detected by the trusted Arduino UNO whose serial monitor input was used as reference. This test worked as well: depending on the fretting hand position (below or above threshold of 5th fret) the resistance values changed. This basically means that the whole left hand setup is working. In the final setup, the change of the resistance values will be used to control the WET/DRY mix of the two FX loops.