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Close range sensors
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Close range sensors

by decarlo on Wed Sep 06, 2017 4:44 pm

Hi, I'm looking for a sensor that will give me accurate distances at close range. I want to place a sensor about 7 inches from an object and measure how far the target travels towards the sensor. I'm looking to read from 0 to 4 inches, so there would be about a 3 inch space from the target at max distance to the sensor itself. Do you have a sensor that can do this? And work with an Arduino UNO? Thanks!

decarlo
 
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Re: Close range sensors

by adafruit_support_bill on Wed Sep 06, 2017 5:47 pm

We have the Shart IR Rangefinders, and also the Time-Of-Flight laser sensors that will work in that range.
https://www.adafruit.com/?q=ir%20distance

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Re: Close range sensors

by decarlo on Wed Sep 06, 2017 8:18 pm

Hi Bill, Thanks for the quick response! I bought both of those sensors from Adafruit. Is there a way to narrow or 'focus' the scan field on one or both? I'm trying to track a metal saw blade that's 1/8 inch across. Thanks!

decarlo
 
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Re: Close range sensors

by adafruit_support_bill on Wed Sep 06, 2017 8:34 pm

Are you looking edge-on at the blade? Both of those sensors will perform better with a wider target.

And if you are looking edge-on - is the blade moving or stationary? There will be some distance between the cutting tip and the gullet. If you can provide more detail about what you are trying to achieve, we might be able to suggest a workable sensing solution.

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Re: Close range sensors

by decarlo on Wed Sep 06, 2017 8:54 pm

I would be looking down at the edge. The blade can be spinning or stationary. If stationary, I can zero out anywhere along the blade (gullet or cutting edge) and take readings from there. If spinning, I'm not sure it will always read the highest point of the blade. Ultimately, I want to use the reading to display the blade height. I have the software and hardware set up, I just need a good sensor or a better sensor set up. Thanks for helping!

decarlo
 
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Re: Close range sensors

by adafruit_support_bill on Thu Sep 07, 2017 6:35 am

Sounds like you are instrumenting a table-saw. The blade itself is a difficult target due to the narrow profile and the teeth. You could probably do something with lasers and a CCD array. But it would be fairly complex and the alignment would be tricky. The arbor and trunnion will move with the blade and represent much easier targets for common optical sensors. Or you could even invert that and mount the sensor on the arbor assembly. For example, you could use a TOF sensor mounted to the top of the arbor and aimed at the underside of the table. You can make a direct measurement on the blade itself to calibrate the system, then all movements would be relative to that.

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Please be positive and constructive with your questions and comments.