In my senior engineering design class for high school, my teacher bought a toaster oven and microcontroller and tasked my group to make surface mount digital dice kit for him to teach surface mount soldering to his digital electronics classes. He bought a couple kits from Beta Layout, but since the parts are discontinued, it is rather hard to reverse engineer.
I found a through hole soldering dice kit on spark fun (https://www.sparkfun.com/products/10212) and found that I could easily convert this to a surface mount kit, especially because the design is open source. However, I ran into an issue, the sparkfun dice rolls using a piezo assembly which is not practical for our kit. I was wondering if there were any professional electrical engineers that would be willing to help my group understand the circuitry behind a piezo, and how I might go about replacing it with a push button. (SPST?, SPDT?)
Best Answer
You don't really need to understand how the piezo works, because a button is much simpler. Just take out everything connected to the piezo (
R5andD1) and replace it with a SPST, normally-open momentary button. Connect one button pin to theGP0pin and the other end to ground.You'll have to change the firmware to enable the internal pullup on
GP0, to use it as a digital instead of analog input, and to use some other source of randomness. Maybe some sort of timer during debounce.