I have a few questions/comments about this circuit.
http://www.dakeng.com/spindle_ckt.jpg
LM339 is a Quad circuit and only one circuit is used?
14-Dip comparator (differential/offset)
why not use one of those single circuit TO-5 little metal cans or even an dual circuit 8-Dip (LM393)
would not a high seed one be better?
7404 has 6 circuits and only one circuit is used?
What is it?
Gate?
PIC?
cnc4pc.com's Index Pulse Card uses a HD74LS04 which has 6 circuits and only uses one circuit
http://www.wrathall.com/Interests/CN...le_encoder.htm
http://www.wrathall.com/Interests/CN...der_layout.pdf
This looks much simpler;
http://groupyahoo.com/group/turbocnc...ndexSensor.zip schematic.jpg
This look better yet, it's all ready built
http://www.wrathall.com/Interests/CN...ion/GP1A05.pdf
The local Radio Shack don't have most of these pieces.
The have the infrared diode/emitter, don't have the detector.
So I'm looking at buying the pieces from Digi-Key, Jameco, Mouser, Newark InOne, ...... and replacing the LED and detector with a slotted unit.
Something like cnc4pc.com's Index Pulse Card (ECG3100) OR ajaxcnc.com's Z-axis Optical Limit Switch
Then again with a reflective flag and a reflective sensor I could make something like industrialhobbies.com's optical limit switch.
Are usec. and nsec. the same or is ns much faster than us?
Wile searching the net I found a circuit that uses a LM358. One electrician said it would be faster than the LM339 but it would cost more. The 358 is an amp not a comparator.
Also, I've found out that this will also work as a switch.
Wouldn't this do the same thing?
http://robotics.me.jhu.edu/~llw/cour.../lab_02_09.pdf
or this
http://www.electronics-lab.com/projects/misc/017/
I guess I'll just have to buy some pieces and run a few tests.
Bill