QEDS-9500/HP Deskjet
Posted by
stratton@x...
on 1999-09-23 13:29:07 UTC
So after reading Mike Romine's post in archive #47 that the majority
of HP optical encoder modules were made for internal consumption in
printers, I decided to take apart an old HP deskjet that I had
already raided for its tiny unipolar stepper.
Turns out the printhead is driven by a two-wire DC motor and monitored
by a QEDS-9500 optical encoder on a 1.5 inch code wheel. The
resolution is obviously coarser that the 360 lpi strips I just bought
from US digital, but the basic idea looks the same, and I'm assuming
the pinouts will be compatible. Anyone know what the resultion on
this is? Obviously I can figure it out, but I don't find any mention
of this particulr HP module on the web. Interestingly, the code wheel
is metal with holes in it, rather than mylar with printed lines.
I figure it might be usefull for something... put it on the spindle if
nothing else. The motor is too small to be of much use, but might
make a nifty servo demo when used with the encoder.
There is also an L298 stepper driver on the main logic board, which
surves to boost the salvage value by a couple bucks.
Chris
--
Christopher C. Stratton, stratton@...
Engineer, Instrument Maker & Horn Player
(978)538-5179 work, (617)492-3358 home
30 Griswold Street Cambridge, MA 02138
http://www.mdc.net/~stratton
of HP optical encoder modules were made for internal consumption in
printers, I decided to take apart an old HP deskjet that I had
already raided for its tiny unipolar stepper.
Turns out the printhead is driven by a two-wire DC motor and monitored
by a QEDS-9500 optical encoder on a 1.5 inch code wheel. The
resolution is obviously coarser that the 360 lpi strips I just bought
from US digital, but the basic idea looks the same, and I'm assuming
the pinouts will be compatible. Anyone know what the resultion on
this is? Obviously I can figure it out, but I don't find any mention
of this particulr HP module on the web. Interestingly, the code wheel
is metal with holes in it, rather than mylar with printed lines.
I figure it might be usefull for something... put it on the spindle if
nothing else. The motor is too small to be of much use, but might
make a nifty servo demo when used with the encoder.
There is also an L298 stepper driver on the main logic board, which
surves to boost the salvage value by a couple bucks.
Chris
--
Christopher C. Stratton, stratton@...
Engineer, Instrument Maker & Horn Player
(978)538-5179 work, (617)492-3358 home
30 Griswold Street Cambridge, MA 02138
http://www.mdc.net/~stratton