Did you ever have one of these?
They are fun to complete, but what do you get when you collect them all? NOTHING. No compliments. Well I made one for budding numismatists among us, with the sweet sweet neurological reward of a blue light turning on upon completion:
My original idea was to make a coin dish that “switched on” when conductive coins (i.e. pennies, but not quarters) were added. I made the coin bowl.
![](https://media.giphy.com/media/7gSvrTRbA8ZzO/giphy.gif)
But It turns out that along with aluminum foil, all coins are conductive. This includes old “silver” dollars and Bahamian money.
![](https://www.blog.calebfergie.com/wp-content/uploads/2017/09/IMG_1550-2.jpg)
So, important lesson, always test your components! Unit test ( i.e test them in an isolated environment) if possible. I suppose the same goes for debugging.
Instead we take advantage of their conductivity and the material immediately available on the floor: cardboard and tin foil!
![](https://media.giphy.com/media/M6NlhTKvaIIAU/giphy.gif)
Hopefully future fabrications will be less brutish. A little paint and labelling would certainly go a long way. But this will do for now.