Phone diagnostic bench loading
Grab a handful of salvaged phone parts, wire them to one board, and let the LEDs tell you pass or fail. This guide walks you through the full build in clear order. Your progress stays on this device, so you can close the tab and pick up right where you left off.
Every test follows the same four stages, whether you are checking a charging port or a battery cell on the header pins.
Clip the salvaged part into the matching header: port, speaker, motor, earpiece, or battery.
The microcontroller reads the signal that matters for that part: voltage, continuity, current, or a response pulse.
Firmware checks the reading against a safe range you programmed for that component type.
A green LED lights for pass or a red LED for fail. No multimeter needed once it is calibrated.
Twelve short steps in order. Open any step to read it full screen. It marks itself complete as you move through. Come back anytime; nothing resets on its own.
Everything the build needs, listed the way a technician would want to see it on the bench.
Select a part and run a full diagnostic. The app checks connection, senses the signal, compares it to the safe range, plays a beep at every stage, and gives a clear pass or fail. When hardware is available it uses real sensors (device battery, vibration, or a USB serial board). Otherwise it runs a high-fidelity simulation that still works on any phone or computer.
Practical notes that sit alongside the step-by-step guide.
The Nano keeps things simple and cheap for a wired bench tool. The ESP32 adds Wi-Fi, so you could optionally log results to a phone or laptop over the network.
Salvaged lithium cells should only be tested through a current-limited circuit, never bare-wired. Let an experienced electrician lead this part of the build.
Prototype every header on a breadboard and confirm each pass and fail threshold before committing to a soldered PCB and enclosure.