Sometimes the projects we think are easy to design are the ones on which we end up making the most mistakes. The UNIX clock that you see in the picture above is one of these projects. For our readers that don’t know it, UNIX time is the number of seconds since 00:00 on January 1st 1970. The clock that [James] designed is based on an Arduino Pro Mini board, an RTC chip to store the time, a custom made display board and two buttons to set the date/time.

One of the mistakes that [James] made was designing the boards on which will be soldered the seven-segment displays before actually choosing the ones he’ll use, as he was thinking they’d be all the same. The displays he ended up with had a different pitch and needed a different anode voltage, so he had to cut several traces on the PCBs and add another power supply. It also took [James] quite a while to remove the bits that his hackerspace’s laser didn’t cut through. We strongly advise a good look at his very detailed write-up if you are starting in the electronics world.

If you find this Unix time display too easy to read here’s one that’s a bit more of a challenge.