One of my first forays into circuits - a carputer! While driving, it collected data from the OBD2 port. As soon as it saw my home WiFi network, it dumped everything into my dashboards. I selected TinyCore Linux, which resides entirely in RAM, to avoid write caching issues after a sudden power loss (turning off the car).
The sales guys at an HVAC company wanted a way to upsell air quality treatments, so I built them a handheld air quality monitor. Why confuse the customer by explaining that their VOC levels are 150ppm when you can just flash a red light?
JTAG debugging an early version of an industrial control board.
The final version of that control board - powered by Texas Instruments.
Power supply for the control board; transforming 120-230v AC to 9v DC.
Reading outputs from the control board on an oscilliscope while watching the serial logs.
Building a new doorbell - this one texts me instead of playing a chime!
Running a new branch circuit for hardwired / interconnected fire alarms.