These days, the electronics hobbyist is lucky to have access to a wide range of ready-made modules that enable sensors, screens, and microcontrollers to all be linked up with ease. However, this manner of working generally ends up with a project that becomes more of a PCB salad than a finished product. Oftentimes, it’s possible to find something off the shelf that’s close to your requirements, and repurpose it to work. That’s exactly what [Aaron] did.
[Aaron] wanted to install a display in his classic Jeep to display the time and some basic parameters. A screen and a microcontroller were called for, and a cheap open-source transistor tester had exactly that already. Consisting of an ATmega-328P linked up to an 128 x 64 graphic LCD module, it had most of what [Aaron] needed from the get go.
To repurpose the device, [Aaron] started by swapping the 8 MHz crystal for a 16 MHz one to make it more easily programmable through the Arduino IDE. Then, a custom firmware was written, which communicates with a DS3232 real time clock, temperature and pressure sensors, and also monitors battery voltage. It’s all neatly installed in the vehicle behind a 3D printed faceplate, and the graphic LCD is clear and easy to read – if you speak German.
[Aaron] has helpfully outlined the various online resources that helped with the hack, including the transistor tester schematic. Our very own [Adam Fabio] reviewed these units in 2015.
If you’ve cleverly reused some existing hardware yourself, be sure to let us know on the tip line. Video after the break.