IR Sensor Issues

I'm learning the Parallax BoeBot in preparation for a class I'm assisting and I'm trying to figure out if everyone has the same issues
with the IR sensors that I am having.
I set up the BoeBot with the IR sensors from Parallax and everything works fine, except that the sensors seem to fail all the time. Over the course of 6 hours I had to replace 2 different sensors. According to the professor, they had the same issues in the past as well. Does anyone know if this is a common problem with the parallax IR sensors, or if there is a workaround? Any advice would be useful.
Thanks, Ross Boucher snipped-for-privacy@usc.edu
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did the sensors stop giving you any signal at all? or did they just behave erratically?
fluorescent light bulbs can interfere pretty badly with IR sensors...
snipped-for-privacy@gmail.com wrote:

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They stopped giving signal at all -- I was outside in natural lighting.
Andrew wrote:

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Which I sensors are these? They have several types (prox, distance measure, etc.).
Call their customer service and get replacements. I'm sure they'll tell you if there are workarounds to a common problem, as such a problem could get very expensive for them.
-- Gordon
rboucher wrote:

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Hi Ross,
rboucher wrote:

I've seen a couple types of failures. Maybe one of these fits your situation.
One is with the GP2D12 like sensors (IR Ranging). These often develop stress fractures in the solder joints where the 3 pin connector solders into the circuit board. The stress fractures are a result of the flexing and force required to insert and remove the connectors. Once the fracture develops, you can get intermittent behaviour, or the sensor will appear to fail. Sometimes moving a cable will make it go from working to not working.
Remelting the solder will remove the fractures.
The other failre that I've seen relates to the QRB1134 style of IR sensor. These are basically an angled LED and photo transistor. It's very easy to blow the IR LED by allowing it to draw too much current. This is typically caused by choosing current limiting resistor which are too small. All it takes is an instant, so I usually get this type of failure on the bench when playing around. You could also get it if your current limiting resistor is right on threshold of allowing the IR LED to fail. A small voltage spike can push it over the edge.
--
Dave Hylands
Vancouver, BC, Canada
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