Photo sensor for red LEDs
CliffS
Posts: 12
Hi gang,
I'm sure there is an obvious answer but here goes:
I wish to make a line follower that uses red LED's (not IR). The system will need a lot of LED's & sensors (like about 20 led - sensor sets)
The LEDs are easy. I'm looking for photosensors (photo diodes?) to sense the reflected red light.
Any suggestions on the cheap photo detectors for this? I suspect that a typical photo-resistor is too slow of a response.
(I understand that an LED can be used as a photo sensor - any idea how to hook it up to a Basic Stamp input so that it will turn the digital input on/off when light is on/off?)
Many thanks!
-Cliff
I'm sure there is an obvious answer but here goes:
I wish to make a line follower that uses red LED's (not IR). The system will need a lot of LED's & sensors (like about 20 led - sensor sets)
The LEDs are easy. I'm looking for photosensors (photo diodes?) to sense the reflected red light.
Any suggestions on the cheap photo detectors for this? I suspect that a typical photo-resistor is too slow of a response.
(I understand that an LED can be used as a photo sensor - any idea how to hook it up to a Basic Stamp input so that it will turn the digital input on/off when light is on/off?)
Many thanks!
-Cliff
Comments
-Phil
Most photoresistors (photocells, LDRs, CdS cells) are most sensitive to yellow-green light. And true, they have much slower response than phototransistors, but could still be plenty fast enough for a line following robot under the right circumstances. You won't be doing any high-frequency switching in line following mode.
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·"If you build it, they will come."