Sharp IR sensor filtering

Forum 2005-2010 (read only) Hardware Troubleshooting
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Hi people,

Ive come across the need to filter the noise out of my very noisy sharp IR sensor for my rover bot. it seems the general consensus is to solder a 10uf capacitor from vcc to ground however at the electronics store icouldnt find any 10uf non polarised caps so i had to settle for 22uf (polarized film caps) and 0.1uf ceramic caps.

which is the better for me to use? can i even use polarized capacitors for this application? i do have alot of resistors here too and i see some people recommend soldering a resistor in parralel with the output pin if i recall correctly.

also as a side question to this. i notice my readings became in accurate on the rover when the servo is moving the sensor left and right in a sweep. if the servo stops the reading is stable (sort of with noise) however if it is moving i can get readings like 3 then 150 in the same position. Is it possible that the servo is generating electrical noise that the sensor picks up?

Thanks :wink:

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just noticed i made this in the wrong forum doh!

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You can connect two of your polarized capacitors back to back (plus to plus or minus to minus) to make it non-polarized.

Move the sensor by hand while taking readings to see if it's the physical movement or servo noise causing the problem. I doubt its RF noise from the servo, but if it is you can reduce this by winding the servo lead around a ferrite toroid : http://www.goldmine-elec-products.com/products.asp?dept=1050 If you have an old computer power supply in your junk-box you can probably pull one out of that.