high speed tracking

[sraque]

I can also recommend the CTRE magnetic encoder:

http://www.ctr-electronics.com/senso...c-encoder.html

As well as the CUI AMP 10 series of encoders:

http://www.cui.com/catalog/component...mental/modular

We have successfully speed-controlled high speed wheels with both of these encoders directly connected to a Talon SRX.

Both encoders are available from AndyMark.

[BDRessler]

Originally Posted by sraque

I can also recommend the CTRE magnetic encoder:

http://www.ctr-electronics.com/senso...c-encoder.html

As well as the CUI AMP 10 series of encoders:

http://www.cui.com/catalog/component...mental/modular

We have successfully speed-controlled high speed wheels with both of these encoders directly connected to a Talon SRX.

Both encoders are available from AndyMark.

We use the CUI AMT-103 encoders, they are super nice because they are robust and have an adjustable resolution.

[Gdeaver]

I'll 2nd the CUI AMT102 or 103. We have used them for the last 3 years and they have been rock solid. We got the AMT102 on the shooter Sunday hooked into a Talon SRX at 512 resolution. Testing done at 4100 to 4300 rpm. Using FPID looks very good but the graphs show that we need a fly wheel. CRE has done a good job. Proud of the programmers. They studied the CRE manual and got it up and running in a couple hours. This is not easy but with CUI and CRE we are getting there.

[dtengineering]

A more basic approach might be to use a reflective object sensor, such as a QRD1114 (or OPB706A, or any of a wide range of IR reflective sensors) and a bit of reflective tape on your wheel. If your wheel is already reflective, then use non-reflective tape... anything so you have part of the wheel reflective (shiny, white) and part of it non-reflective (dull, black). The non-reflective part could also consist of a hole in the wheel... anything that doesn't reflect IR light back into the sensor. You have to add a couple resistors to the QRD1114, but you'll find plenty of tutorials on how to do it.

This way you'll get one pulse per revolution... just use the RoboRio to time the interval between pulses and you're set. You can achieve the same thing by looking at the shaft... paint half of the shaft flat black, and leave the other half shiny.

Do note that the effective range of the QRD1114 is about 1mm. And that it has 1114 in it's name. If it's 1114, that means it's got to be good, right? :-)

Jason

[Ether]

Originally Posted by dtengineering

just use the RoboRio to time the interval between pulses and you're set.

Just highlighting this for emphasis. For a one-per-rev sensor, do not count pulses and divide by time.