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Rotating monitor construction *Project finished*
DaOld Man:
Yeah I know.. I went through the same problem when I first started this project.
(Several posts back). :banghead:
On my desktop all outputs came on for a few seconds, then all went off.
I wired a fix for that in my isolator board, using a PNP transistor that cut the ground off to the opto isolators if Pin 7 was high, but evidently on this other computer pin 2 is staying high longer than the others, because pin 2 comes on after a slight pause and stays on until Windows starts to load. Since I am using pin2 for one of my drive's directions, this aint gonna fly.
I wont be able to tell for sure what is going on until I get my output tester built, then I can monitor all of them.
DaOld Man:
Ive been playing around with my printer port tester.
I changed it a bit to allow me to adjust PWM "on the fly".
Ive been able to get my motor speed down to about 1 RPM
Remember though, that my motor has a gearbox. Output at full speed is about 55 RPM.
Here is a screen shot of my latest printer port tester.
I added checkboxes so you can choose which output(s) to pulse for PWM.
I also added buttons to increase/decrease speed in increments of 1 and 50.
I added ability to change input scan time.
I also added a couple of blinky lights to tell that the inputs are being updated.
edited to show a better screenshot
DaOld Man:
I have been playing around with Pulse Width Modulation using my printer port tester.
I have found that about the slowest I can efficiently get out of my motor is a pulse of 38 milliseconds off and 8 milliseconds on.
I can take it slower than this, but the motor jerks pretty bad.
Im estimating the RPM at this PWM to be approx 10 RPM.
My motor is very hefty, and it has a gearbox, I think a small motor would run a lot smoother at low speeds.
The power transistors on my H Drive are getting pretty warm at this speed. I can see now why the transistors failed on my earlier tests. My first H drive had no heat sinks on the power transistors.
I can see where the transistors will fail under these conditions without proper heatsinks.
I probably wont need speed control on my setup, but it is fun experimenting with it.
I wonder how this program would work on the secret motor driver the LCD guys are working on?
DaOld Man:
Just a quick update.
I may have to redesign my rotate design.
The machine I plan to install it in (Benny B's Arcade), is very short on room in the monitor area. :banghead:
When I built Benny B's, I never thought I would be installing a rotating monitor.
I almost decided to go back and make the original monitor installed in it (17") rotate.
Nah, I like challenges. It's gotta be the 19". Too far to turn back now. (or is it???)
So I got to get out the saws and do some re-constructive work on Benny B's.
Pictures soon, soon I say!
koz319:
Is the depth of the monitor the issue?
The 21in. CRT I put in mine (an old NEC Multisync) was freaking huge. I did a bit of planning/playing with the tilt of the monitor to reduce it's footprint front to back. There was no room to attach anything to the rear of the monitor, so I went with a 2 'wooden wheel' setup. I attached a couple pics, I have some better ones somewhere I will try to find.
Have fun!
Koz
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