Double input when using multiple toggle switches

[IanRawz]

Description of Issue

I would like to use 4 toggle switches on my buttonbox, but I just can't get it to work. Whenever I switch the toggle switches on, i'm getting double (or more) inputs from the other buttons. Is there a way to fix this? Thanks.

Technical Details

• Arduino Board (e.g. Arduino Leonardo): Pro Micro
• Host OS (e.g. Windows 10): Win 10

Sketch File that Reproduces Issue

Used the amstudio sketch & guide from youtube https://www.youtube.com/watch?v=Z7Sc4MJ8RPM Sketch: https://bit.ly/3152ALk

Wiring Details

This is my button matrix: (T = toggle, B = button)

A3: T--B--B--B--B
    |  |  |  |  |
A2: B--T--B--B--B
    |  |  |  |  |
A1: B--B--T--B--B
    |  |  |  |  |
15: B--B--B--T
    14 16 10 9  8

• 3 encoders on pin TX,RX,2,3,4,5

[Reisen-Wandern-Tauchen]

It seems that you are facing one of the basic issues with button matrices... it's called "ghosting". You can prevent this by using a diode on each output pin of your switches (to prevent power flowing in the wrong direction) in combination with multiplexed reading (only swith 1 input pin HIGH at a time, then reading all the outputs, then swithing all inputs LOW and switch the next one input pin high and repeat the whole procedure) This article may help: https://www.baldengineer.com/arduino-keyboard-matrix-tutorial.html