In pursuit of a sense of wonder

Lost is the occasional blog of Leon Matthews, programmer and master of miscellany.

AVR Multi-Programmer

I'm about 10 years late to the party, but in this project a cheap Arduino UNO clone becomes a very handy AVR programmer for everything from a little 8-pin ATtiny13 to a 28-pin ATmega.

Automatic Low-Voltage Cutoff

Running a battery completely flat can permanently damage it, lead-acid and lithium-polymer types especially. I put together this circuit to protect a small lead-acid UPS battery. It's cheap, has a high current capacity, and use only very common parts. Did I mention that it's cheap?

Cheap Electronics as a Sudoku Alternative

Today's challenge is to drive a cheap 8-digit LED display. Months ago I bought a cheap module from Aliexpress. Too cheap. Instead of a nice smart LED driver chip as I had expected, it features instead the jewel of 1980's technology: a pair of 74HC596 shift registers. Let's explore this puzzle!