Steve Anderson wrote:Your problem with the Chinese-made module maybe one or both of two things. First, depending on the distance from the disc to the LED and detector, they may need angling in towards each other for better coverage and sensitivity - looking at the photo that may be difficult to achieve. A lot of these devices have a beam-width/sensitivity curve of only some +/-10 degrees.
Second is if the disc markings for this are printed (laser or ink-jet) rather than 'done in hardware' a lot of inks (black in this case I assume) are reflective at IR.
I hope this helps...
Steve A.
Yeah, honestly I went down that route because for some reason I could not figure out why a simple OP-AMP and IR Receiver Diode would not work as it had for me before. You see, I had put the output into an Arduino chip. I had failed to program the chip to have that pin be an input... in fact, I had not programmed it at all and just relied on a led to indicate the mark had passed. The Arduino chip was messing with my results. So I decided to use that module.
When I tried the little module it seemed to show promise and I began programming the Arduino chip and monitoring the time between the mark passing. After determining the module could not really give me the results I was looking for, I plugged back in my IR Led's and my original mistake slapped me in the face. That original circuit worked! LOL. It was the Atmega328 chip and my rush to put it in the circuit without even programming it causing me a weeks worth of grief. It works perfectly now.
I have way too many hobbies and have much more determination than skill.
Thanks for your comment, Steve. The module was so sensitive to any light. I even had it set so close to the disk at one time it would hit here and there. It would still get pulses on an extremely low setting. It was designed for line following robots. Its sensitivity would make it totally useless for that thus making a bunch of kids very sad.