When uising a switch, button, or relay, contact bouncing often occurs, when the momentum of the switches closing cause them to bounce apart one or more times before making steady contact. Think about knocking a hammer
The software “debouncing” solution is to do a state detection. First, detect the switch state state1, then wait for a certain amount of milliseconds (a “debouncing window”), then check the switch state again state2 to see if they match. If state1 == state2, then the switch can be read as being in a steady stage.
Build the Arduino debouncing example.
Note that the example used 50 milliseconds as debounce time. The debouncing window is pretty arbiturary, depending on what siwtch you’re using. This example also used a function called millis(), which returns the number of milliseconds passed since the Arduino board began running the current program. It can be used as a good replacement for delay() as it doesn’t slow the program down. Here is a beginner’s guide to using millis() to keep time if you’re interested.
Many of the analog sensors we use are simple and inexpensive, with is great. But they produce very “noisy” output - unstable and occasionally with glitches or errors. Luckily there is an easy way to smooth the output just using code!
Build the Arduino smoothing example.
numReadings