I have a IR receiver hooked up from Ground to Analog Input 0 (with 235 omhs resistance ). When I read the analogRead(0) it generally gives me readings of 0. This is with the IR-TX covered/off, so I would expect a reading above 0.
Now here is the strange part, if I measure the resistance of the IR-RX with my MultiMeter while the code is running, the value of analogRead(0) starts to reads around 30, which I think is correct.
Why when I use my MultiMeter to measure the resistance across the IR-RX does analogRead(0) start to read correctly?
I randomly tried resistors and capacitors across the IR receiver to see if it would mimic what the MultiMeter is doing but with no luck.
As I am very new to electronics here are some details: MultiMeter : Digital Multimeter set to 2000k to meaure resistance. Arduino: Dumilanove
im pretty sure most multimeters measure resistance by passing a small voltage through whatever you are measuring. chances are your arduino is measuring the voltage your multimeter is providing.
A datasheet for what you're calling an "IR receiver" would be a big help. In my experience you use a phototransistor or diode to detect IR coming from an IR LED. These don't have a resistance as such but the amount of current they pass varies with the light intensity givimg the illusion of having resistance..
You dom't wire phototransistors / photodiodes anything like your connections but its depends on what your "reciever" is.
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This is a reasonable circuit for a IR LED/phototransistor if that is what yours is :
Test point s where you hook your analogue/digital pin or multimeter votage probe to. The switch is optional depending on the intended use.
weirdo557 I think you got it spot on as to why the multimeter makes it work!
Pluggy, I did what you said and it works wonderfully, now I am getting a difference in high/low readings of 100's instead of 10's, which makes life easier.
