Electronics > Electronics

Sharp IR proximity detector vs. DIY emitter/detector/ADC setup?



New to robotics, and thought I'd ask about the practicality of building your own IR proximity detector.  Since an IR LED/detector pair can be had for a buck, what's the drawback to rolling your own?

First thing to mind is ensuring that the detector doesn't have line-of-sight to the emitter.  Second is that it'll take some experimenting to map ranges to ADC readings.

Both of those seem pretty minor obstacles.  What am I missing?

Oh, duh.  I guess the big one would be the Sharp model does all the emitting and detecting automatically, and you just have to read the ADC pin.

If I roll my own, I'll have to do the emitting in code.  And I suppose it probably uses some sort of signal modulation to prevent intererence with other IR sources...  $10 is starting to sound pretty good.

The other big win for the Sharp modules is they are very limited in terms of line of sight, so they are for the most part not affected by typical indoor light sources, including cameras at competitions.

- Jon

Steve Joblin:
You can build your own IR Emmitter/Detector pretty cheap... you only need three components... an IR LED, an IR Detector, and a Microcontroller... If you want to use a Parallax Basic Stamp, check out page 235 in the Robotics with the Boe-Bot manual which you can download here...(http://www.parallax.com/dl/docs/books/edu/Roboticsv2_2.pdf)

The attached provides a small circuit that only uses one Stamp pin!


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