Distance sensor noisy - sample frequency?

Other Hardware Sensors
1

I'm implementing a proximity sensor using an Arduino Duemilanove and the aforementioned Sharp GP2Y0A02YK infrared distance sensor. I have the sensor roughly working so that it triggers if an object is within the desired range but it's still very noisy. I'm just sampling the sensor every 1ms at the minute and then triggering the output if the reading is within a determined range for 100 samples.

Looking through the datasheet, I came across this:

I don't know what to make of that. Is it just saying that you have to wait up to 52.9ms before taking a reading and after that it's all good? Or should I be aiming to read in the middle of each output time window? In which case I don't get how you can clock your readings if there is a tolerance of 25% on the sample frequency of the device.

Any input would be very welcome!

Edit: I had the wrong URL to the image, now that's fixed so it should show up and the post should make a bit more sense!

2

I think you are right. It takes about 53 mS after power is applied to expect the first valid signal. Then, no matter how fast you sample, you get the same answer for the next 30 to 50 mS. I suspect that's how long it takes to do a sweep, depending on proximity. Perhaps you should reduce the sample rate to more like 20 mS.

3

Thanks for the feedback, John, and good work finding the image with my duff link. :expressionless: