I've been using my spare time lately to build something that's even more trivial and silly than usual. Behold, the advice machine!
Operation is pretty straightforward. You insert whatever quantity of coins you see fit, then request some advice from the machine. The quality of the advice you get reflects the value of the coins you put in - more or less. More money typically results in more in-depth fortunes, and more interesting ones such as quotations, while a small amount gets you platitudes or terrible jokes.
Here's a video of it in action:
More photos can be found here.
All in all, the project was relatively straightforward, after a couple of false starts. The coin acceptor is a standard item commonly found on ebay - this one has model number CH-926 - for around about $20-$30. The device has a moderately complex setup procedure whereby you 'train' it on a set of sample coins, and tell it how many pulses to output for each coin. After that, it will recognize coins similar to the ones it was trained on, outputting the appropriate number of pulses on one of its pins when each is detected.
The LCD is a ...