Looking for a hands-free way to page through sheet music on an iPad, [The_Larch] came up with this simple Bluetooth input device based on the ESP32. The microcontroller just needed to have two ...

The device should now respond to esptool etc, and be programmable. Resetting the device may set it back to the broken program. I am using a SIM card from https://hologram.io/, with the Pilot (1MB) ...

Several makes of multi channel relay boards that are controlled over an RS232 serial port. I am testing with a model that uses a ULN2803A chip also noted as a darlington array and an RS232 level ...