Help me plz 4x3 keypad.

jayzdaboss

Can someone plz help me and give me a example code or something

I'm trying to make a pass code entry.

If you can help that could be great.

Clive Wakeham

How is your keypad interfaced with the BasicStamp?

I have wired up a 4x4 keypad to a 74C923 Keypad IC, there is also a 74C922 keypad chip which is part of the pdf file.

I have included a PBasic file for reading the the keypad via the 74C923 . Where as the 74C923 provides debouncing, my PBasic program is designed so no multiple keystrokes appear unless the key is released and then pressed again.

The lookup table can be adjusted in case the wiring to the keypad doesn't match exactly to the 74C923 (74C922)
chip.

jayzdaboss

Thanks I'll try it out and see if it work.

Clive Wakeham

You could also interface the keypad directly to the BasicStamp using 7 pins for the 3x4 keypad.

For example you could have pins 0 to 3 as output, and 4 to 6 as input.
Then make pin 0 high and then check each pin 4 to 6 for a high to determine if the button is closed, then pin 1, then pin 2 etc etc.
That would save you having to make up a circuit with the 74C922 or 74C923

I am using a 74C923 because my design is complex, expandable, and will be interfaced with a Propeller rather than a Stamp. Its only that I am testing my design with the stamp I have at the moment...... My Prop is on order.