When I realized I wanted to take my calculator collection more seriously, I ordered the KKMoon DIY Calculator Counter Kit from Amazon. It was only $15 and seemed like a fun project. The parts ended up sitting in a box in my closet for several months but this past weekend I decided to sit down and finally put the thing together.
|KKMoon DIY Calculator. Fully assembled.
Unfortunately, the acrylic case proved to be an agonizing endeavor. Peeling off the protective covers on each piece was easily the worst part of this entire experience. The second worst part was assembling the keys, which use tiny pieces of paper you have to cut out. The buttons look terrible.
It took me two hours to build, and the end result is pretty cool. You can see inside the device and with the exception of the buttons, the calculator looks great. The display is bright and back lit, unlike any other device in my collection.
While the buttons look ugly, they feel fantastic. They're loud and clicky and extremely responsive.
In addition (haha) to the basic mathematical functionality, this device is also capable of determining the resistance of resistors by inputting the color rings. I haven't had much luck with this and I don't know why. Maybe the resistors I was looking at used a different system?
You can also use this calculator to determine the needed resistance to use an LED by inputting the source voltage and the working voltage of the LED.
|Hex calculator in action.
|One of the two CR2032 batteries. Impossible to access without disassembling entire device :(.
Here's the complete build video. It's two hours long and probably very boring.
|Basic calculation. Display has a minor defect that affects the second from last digit.
|This device is incapable of calculating very large numbers.