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The Rotary Table Page
This is the rotary table project that started this encoder project.
At this time I have no images of of the rotary table itself, those will be added later. These first images deal with the encoder (taken from a mouse) that was added to the back of the gear motor that is to be used to drive the table. Originally the table was hand crank.
This is the whole motor, encoder added. The encoder is protected under a
plastic cover that I turned on my metal lathe.
This is a peek inside with the cover pulled partly back.
And this is the encoder. Notice the optical wheel from a mouse, and the
reader / LED for it. The larger blocky thing is a optical interrupter for
the index pulse, I drilled a hole in the wheel for the index.
Both LEDs are in series along with a 47 ohm resistor across the 5 volt
power, as per how the mouse was done. (The mouse also had two LEDs, one
for each wheel.)
The reader for the A and B channels is a complete chip, TTL output, no
pull up resistors used. The index channel though is just a bare NPN
transistor (no base lead) with the emitter grounded and a 4.7k pull up
resistor on the collector from which the index signal is taken (TTL
basically).
It was bench tested with an oscilloscope, all signals looked good, the electronics seems quite fast. I had been worried that the optos from the mouse might be of poor quality and slow, but this seems not to be the case. I have not tried it yet with the computer (running EMC2) as other things are needed first.