Arduino Forum

Using Arduino => General Electronics => Topic started by: kartoffelnsymbols on Mar 23, 2013, 07:13 pm

Title: soldering LEDs for use as sensors
Post by: kartoffelnsymbols on Mar 23, 2013, 07:13 pm
Hi. So I'm trying to use an LED as a light sensor by applying a positive voltage to it backwards and then counting down how long it takes to get to 0V, similar to this:

http://playground.arduino.cc/Learning/LEDSensor

the problem is, whenever I try to solder anything on to the LED, it takes far less down to count down. I'm guessing I'm changing its capacitance, but I'm not sure. Am I just epically bad at soldering or is there some way to not screw up the LED?
Title: Re: soldering LEDs for use as sensors
Post by: MarkT on Mar 23, 2013, 09:54 pm
If it discharges faster this means you are adding more leakage current.

What are you soldering to it?

Also its possible to damage the LED by soldering for too long (LEDs are often more sensitive than
silicon devices to heat), thus changing the natural dark leakage current.