Gene Pierson admits that “flash cards for a 10 year old girl are boring, and he’s getting tired of trying to convince his daughter to do them. It’s a struggle many parents are certainly familiar with, and — also like many parents — he resorted to bribery.
What he came up with is a system where if his daughter gets the right answer, she presses a button, which triggers an Arduino Uno clone to activate a servo. This pulls the lever of manual counter via a linkage made out of bent wire, showing how many problems she’s done.
One could see such a device linked up to a math app itself at some point, but rather than go down that path, he instead reprogrammed it to act as a random number generator. Programming here is pretty standard, using an analog input as the seed value, and the “random” command to generate a number between 1 and 20. With this number generated, it then shows the value manually in the same manner as the math problem counter.
Theoretically, the value could go up to 999 here, and perhaps it could be used for an enhanced answer game, where if you hit a random “jackpot” the number goes up by a random value rather than one to keep his daughter’s attention. Pierson notes in the full title that this is a “completely useless yet useful” device, but this concept could certainly inspire other project ideas!