I use a lot of ADC ports, mostly for monitoring switch position. I have been using the ports on EZB v4's and found out early I needed to use pull down resistors on the cables between the EZB and the switch. The signal going to ARC would jump around a lot and make it impossible to set a high and low value that would tell ARC if the switch was open or closed. The swing in the reading would cause my scripts to start when not wanted. Adding a pull down resistor between the signal wire and the ground wire stabilized the reading completely. No more issues and no worries using the ADC ports on an EZB for this.
Well, I needed more ADC ports (and a couple digital ports) so I got an IoTiny. It was no surprise that I found the same issue. The floating ADC pins gave me wild signals when monitored in ARC. I added a pull down resistor to the cable attached to the ADC port monitoring my switch but it did nothing. Still the same floating behavior can be seen when monitored in ARC.
I don't understand the difference in the ADC ports of the EZB and IoTiny. I can move the switch's cable (with the pulldown resistor attached) from the IoTiny to an EZB and the signal is very stable. The voltage is around 3V.
Any ideas? Do I need a different value resistor? I think I'm using 1k right now. EDIT: I'm using 10K resistors.
EDIT: I'm using 10K resistors.
There isn't a difference between the two - maybe it's the wiring? or something loose? Hard to say. Could be the resistor value but that's more a Jeremie question lol
I solved my issue. It turned out to be a grounding problem. So you were actually correct DJ. I couldn't figure why I'd have such a issue with a floating pin even after I installed a pulldown resistor. All I could figure is there could be a ground wiring problem. Installing a resistor from the signal wire to the ground wire of the cable did nothing. So I rewired the power feed of the problem IoTiny to the same spot the good EZB was fed from. The reading is now rock steady. Don't even need a pulldown resistor.
Woohoo! Another one bites the dust
Lol, well I should have looked at the community page before doing my test.
I tested every ADC port on the EZ-Bv4 and IoTiny with a 10k in pull-up configuration then pull-down. Verified that every port was all good, reading 0V when pulled down and 3.27V when pulled up.
Awe sorry man. I didn't mean to waste your time. I'm sure you have so much on your plate. Thanks so much for jumping in to help though.