Initial hardware design thoughts

A project log for hgSynth

ESP32 based monosynth embedded in bass guitar

igor-brkicIgor Brkic 05/02/2018 at 20:410 Comments

This is the first project log and will be mostly about choosing components and technical decisions.

ESP32 comes in different shapes and sizes. For prototyping it's easiest to take an existing board (even though using just ESP32 module isn't too much effort).

For this I realized I have few ESP32 based TTGO Lora boards which have small OLED display and LoRaWAN radio and which I don't really need (I bought 433Mhz version by mistake as local Lora community uses 868MHz). Positive side of this board is that it already has OLED display mounted. Negative side is that it is soldered to it and must stay near the board - I can't put board inside the bass guitar and the display on the front side. II solved this problem by attaching another similar display in parallel to this one.

I still haven't decided should I put the display on the front side of the bass guitar (for the "audience" and as a gimmick) or inside the "top side" (for me, and to be useful when used as a tuner). Also, I need to test will  the overall signal be affected by adding WiFi/BLE radio near the electronics :).

Besides the ESP32 and OLED, on the hardware side we'll need a touch strip (I had one lying around) and two push buttons (one for synth control and another one for changing presets and turning WiFi on/off. Few resistors and capacitors will also be required for input/output signal conditioning.

And now to the software side...