Spindle encoder ideas needed

Hi,
i am thinking of fitting a encoder to the 3.2kw 24.000rpm water cooled spindle.

Now i know of the rotary encoders, though there needs to be some fitting done and they are not so cheap.

I was thinking of sticking reflective material to the shaft and using some kind of infrared sensor mounted apart very near to the shaft. The best would be if no additional electronics are necessary and that the signal output is 24v or 5v, so that it can be read by the BOB. My BOB/galil/ has separate encoder inputs also. And if can be found cheap-20-30euro :pirate:.

Any ideas how that can be done? Any reason not to be done like this?

I'm assuming you want to measure speed ?

Your VFD may have an analogue output that can be set proportional to the speed.

Or a motor similar to this should act like a generator if it is driven by the spindle. I don't know if it is possible to attach it to the spindle shaft though on your machine.
http://www.amazon.com/20000RPM-1-5-3.../dp/B00D0W6W5M
The ouput would be proportional to speed. If you could find a 5v or 24v that would be ideal.

But maybe you are just looking for an index pulse for each revolution ?

If you actually need an encoder, then look in the first post on my build log as you can see in the photo the encoder I used and how I mounted it to the 24000rpm spindle:

http://www.mycncuk.com/threads/6484-...strong-machine

If you just want a measurement of the spindle speed, then fashioning a single pulse is probably easier. Be careful not to add anything which could imbalance the spindle...

Hi,
Jonathan, i remeber your build, i looked around and the encoder was around 60-70euro. I was thinking of something like :

http://www.ebay.es/itm/Photoelectric...3984c5d&_uhb=1


http://www.ebay.es/itm/Arduino-Photo...51f752c&_uhb=1


or to fashion something from these:

http://www.aliexpress.com/item/DC-10...723604177.html



One interesting i found was there very cheap magnetic sensors encoders /~10.000rpm max/ that count the teeth of a pulley, just an idea for a cheap closed loop.

http://members.shaw.ca/swstuff/spindle-encoder.html