This four-digit wristwatch is built using “small size Nixie tubes” — though snekooei doesn’t specify which models he actually used. They appear to be IN-16 Nixie tubes, or something similar. An Arduino Pro Mini with an RTC is used to keep the time, and a button is used to cycle through the different information display modes. The rest of the components are used to drive the Nixie tubes from a pair of 300mAh LiPo batteries.
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