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 switches wired into the GPIO pins, in this case the same heavy-duty plungers you’d find on a guitar pedal, and a USB bulkhead pass-through to provide power. Thanks to the excellent ESP32-BLE-Keyboard
library, it only took a few lines of code to fire off the appropriate key strokes when the left or right button was pressed.
While undeniably a simple project from an electronics standpoint, the wooden enclosure [The_Larch] built is an interesting change of pace from the 3D printed fare we normally see around these parts. It started life as strips of oak reclaimed from an old kitchen table, which were laminated together to make a solid block. A large spade bit was then used to bore into the block to make a void for the electronics, and a second flat piece of oak was fashioned into a front panel.
Creating Bluetooth input devices with the ESP32 is so incredibly straightforward that we’re honestly a little surprised we don’t see the trick used more often. Especially when you consider all of the custom made keyboards that have graced these pages over the last couple of years. The tools are available for anyone who wants them, so you have to wonder if hackers just aren’t fond of using Bluetooth for something as important as a keyboard?
Next step: batteries?
Wireless power over WiFi or BT!
…or grab power from the clicks via piezo?
That might need a different MCU…
https://www.youtube.com/watch?v=qZ0Z18CcTzI
Adafruit used to sell a device that took 8 input switches and connected to a pic as a Bluetooth keyboard. I used them all the time from custom buttons to run Kerbal Space to an adjunct keyboard for a CAD system. Also did STEM builds with middle school inventors with a variety of switches to make cool controls. Miss those little boards, they were very cool