TriDiag Business Card
Gammawave's business card form factor PCB features three diagnostic tools.
According to project creator Gammawave, “The electronics enthusiast can never have enough diagnostic tools at their disposal.” Normally having diagnostic tools available means obtaining a multimeter, oscilloscope, logic analyzer – and a wide range of other doodads – then dedicating a non-trivial amount of space for storage and use.
The TriDiag is an entirely different take on the test equipment paradigm, and fits three test tools onto a credit card-sized PCB. Tools include a continuity/diode checker, a 1kHz square waveform generator, and a contactless AC voltage indicator. Simple LEDs are used for the continuity/diode test and the voltage indicator, while the non-adjustable waveform generator outputs a signal with no visual indication.
The device runs on a single CR2032 coin cell battery, or it can instead be powered externally via a 1.5 to 5V source. Discrete surface-mount components are used to form all of the indicator tools, and the AC voltage indicator antenna is routed into the board itself. The card's electrical operation is explained in the project write-up, and the board design is available for your edification or duplication.
It’s a very cool design, even if it might be a little thick for wallet storage with the battery and components in-place. On the other hand, one certainly wouldn’t rule out keeping one in your purse or commuter bag for electronics diagnosis on the go. As a bonus feature, it also has a millimeter scale printed on the edge, which could come in handy in a wide range of situations!