Switches, Lots of switches

Looking to have an arduino monitor the status (0,1) of a bunch of switches. Maybe about 50 or so... What would be the best approach? Oh yes and the switches can only have 2 wires...


A Mega can do that with no external components besides the switches themselves.

What's your hold-up?

What is this for?


Momentary or maintained?

What would be the best approach?

How about a 5 by 10 matrix and the Keypad library ?

Just because keypad switches are usually laid out in rows and columns it does not mean that they have to be.

What are the switches switching?
If you want to monitor them, then they must be controlling something else.

If you have only two wire the switch and no extra unused switch terminals, you may be in trouble.

What is the application?

Thanks.. Tom.. :slight_smile:

I'm a big believer in re-purposing an old PS/2 computer keyboard (up to 100+ keys, right?)
That way the keyboard circuitry ends up doing all the scanning and debounce, and the connection to the Arduino is only a couple of wires.