Homemade Clock uses Copper Coins for Capacitive Touch Control | #Arduino

Thanks to forums user philross for sending this in – it’s a great looking build, it’s his first C/C++ Arduino build, and the inset coins a real nice…touch!

This project was a lot of fun. It utilizes the big 1.2 Digital Display with backpack, a chornodot for real-time-clock duties, a passive buzzer for the alarm, and the adafruit 5 sensor capacitive touch sensor all plugged in to an arduino uno.

I wrote the code myself using Eric Ayer’s DS3231 library to support the chonodot’s alarm functions. This was my first C/C++ code…and I’m glad I don’t have to submit it for a grade is all I can say…but it runs, so that’s a win.

I made the case out of dribs and drabs of materials left over from other projects. The top is walnut that I used a burl veneer on. The sides are 1/4″ red oak with 1-inch oak dowels at each corner, the bottom is maple, just because I had a piece that was about the right size. The whole case disassembles into 3 pieces by removing 4 bolts from the bottom that are countersunk into that piece, go through drilled holes in the corner dowels, and screw into brass inserts in the walnut top.

The copper coins are soldered to input leads that plug into the capacitive sensor breakout board. When any of them are touched, it drags that input LOW, and that gets read by the arduino. For instance, the big coin is the alarm on/off button. So, you push it and the alarm LED lights. You touch it again and the alarm gets turned off. The leftmost button is “clock set” to set the time. The next button is “alarm set” to set the alarm time. The third small coin is touched to advance the hours or minutes forward, the last button is used to roll the time back when setting either the clock or alarm. A couple of other bells and whistles in there…but that’s the gist of it.

It was a really fun project…and IT WORKS. I unplugged my old alarm clock (which kept horrible time) and now I’m using the homebuilt one.

By the way…the coins are just copper replicas of real coins and were pretty cheap. The big coin is a 1 oz coin, the smaller “nickles” are 1/2 oz BU coins. I inset them into the walnut burl by using my largest forstner bit in a drill press and then setting the lid up on my milling machine and using a flycutter to tweak the holes out until they were exactly the right size and depth.

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