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View Full Version : QRD1114 white vs black detection



Resilient
04-22-2009, 07:22 PM
I am trying to hook my QRD1114 up to my Axon micro controller to tell white from black on a surface. Right now, if it is far away from a surface, it detects nothing and if it is close it detects the surface.

The problem is, it makes no difference on the surface color. I know I must have wired it wrong, but I checked the drawing a few times and it looks good. I even hooked it up to an analog port on the Axon, and it reads like 250 when far from a surface and around 10 when near a surface, regardless of surface color.

Does anyone know of a good tutorial that shows how to wire a QRD1114 for white vs black detection? Rather than for simply detecting a surface?

Thanks

Resilient
04-22-2009, 11:47 PM
Problem sort of solved.

Turns out, black paper backdrops, actually really reflective when it comes to IR. Who knew.

Like as good or better than white paper. Totally works fine on black paint.

Still would like to see some sort of instructions on how to make a QRD circuit and how to tune it. I am particularly interested in how it actually works. Everything I read suggests to me that the QRD acts like a switch, it's either on or off. But tuning it suggests it acts more like a variable resistor. But the data sheet doesn't say anything about resistance.

Thanks

societyofrobots
04-26-2009, 10:08 PM
Turns out, black paper backdrops, actually really reflective when it comes to IR. Who knew.

Like as good or better than white paper. Totally works fine on black paint.
Colors have *nothing* to do with the IR spectrum. Your eyes can't see it, and colors in itself is just a figment of our imagination.

check this out:
http://www.societyofrobots.com/sensors_color.shtml