BLE Buzzer ESP32

For a photo booth (software: https://photoboothproject.github.io) I needed a wireless trigger. I wanted a large push button, but these are relatively expensive and usually too small to accommodate the electronics I had planned. So I got an ESP32-S, a battery shield, and started modeling.

This is the model that was created: https://cad.onshape.com/documents/db4d39519c299b7e34d5dfd3/w/d993b98b9122bbd27a95ed53/e/5e120b5bba915086d26ab841

I gathered a few other materials from old projects and then wrote the code for the ESP32-S. You can find it here: https://github.com/CTeipen/esp32-ble-buzzer

What does it do?

After activating the power supply via the button on the side of the buzzer, the ESP32-S turns on and searches for a signal via Bluetooth. If the device is not paired, this must be done once. Using the terminal, this can be easily and quickly done with bluetoothclt using trust, pair and connect. On future connection attempts, this will then happen automatically.

As long as no connection exists from the buzzer to another device, the Power-LED lights up and the Bluetooth-LED flashes. Once a connection has been established, the Bluetooth-LED lights up continuously.

Up to this point, the buzzer does nothing when pressed. After connecting, an “Enter” keystroke is sent to the connected device when the buzzer is pressed and the Trigger-LED briefly lights up.

By double-clicking the side power button, the power supply can be deactivated again and the device turns off. The battery charge status can be seen by the LED strip, which is visible through the bottom of the buzzer.

A recess on the side of the buzzer allows charging via Micro-USB or USB-C.

How do I build this myself?

I have included a BOM. In addition to the items listed there, I assume you have a basic set of electronics tools (soldering iron, solder, crimping pliers, pliers, side cutters, hot glue gun, etc.). Some of the items in the BOM are marked as optional. If you want to solder your ESP32-S to the breadboard, for example, you don't need a socket strip. If you don't want to plug in the button for your buzzer, but solder it directly, you don't need any cable lugs. You see where I'm going with this.

You can find a schematic as a picture on this page or the plan file in the GitHub repo: https://github.com/CTeipen/esp32-ble-buzzer
If you want to adjust the schematic, you can use this free software: https://diy-fever.com/software/diylc/

I need a different key to be pressed. How do I do that?

To do this, you only need to adjust the source code (https://github.com/CTeipen/esp32-ble-buzzer) and specify the key (https://github.com/T-vK/ESP32-BLE-Keyboard#api-docs) that should be sent to the connected device.