Question about hooking up buttons....

jknightandkarr

I don't see that there would be an issue, but would it work to take a 3.3v DC supply & run it into a momentary pushbutton, then out from the button to a 150 ohm resistor & finally to I/O pins on the Propeller or into shiftregisters? Like I said being 3.3v I don't see an issue here. I'm working on a project & the layout is very cramped on my display side & there isn't room for resistors like the buttons circuit on the PPDB uses.

Joe

Cluso99

No, because when the switch is open there is nothing pulling the pin to ground. Why don't you replace the 150 ohm resistor with either a 10K between the pin and +3V3 and the switch between the pin and ground OR a 10K between the pin and ground and the switch between the pin and +3V3 ?

Nick McClick

When the switch is open, you need resistor to keep the pin in a known state. Otherwise, you won't be able to reliably read the state of the switch. Usually I use a 10k pull down resistor before the switch. The other side of the switch is connected to 3volts. Nothing wrong with using a current limiting resistor on the other side of the switch, although it isn't necessary with the prop. Here's a sample circuit;

you can disregard the LED's.

jknightandkarr

I've got it figured. Looking over my Prop Ed Labs file. I'll take 3.3v into the switch & then out to the Propeller & into a 10K ohm resistor & onto ground. Been a long time since I've gotten to work on my electronics that I forgot about that. Thanks for the help.

Joe