Rotating monitor construction *Project finished*

[DaOld Man]

Thanks Koz319..
I found that the pin 4 was staying on after bootup, which kills the leds, so I tried the same hooked to pin 7, but had the same thing on bootup.
After much head scratching, I found that if I "broke the ground" with Q1 (pnp transistor) to the inputs, the printer port acts this way.
I took the ground for the inputs and put it to the p-plugs ground, and it has done ok or the last two reboots.
I think Windows is doing some screwy things with my port, and everyone may not have the same experiences I am having.
But for now, the attached drawing shows what seems to be working.
But since I still have not received my optos, I will leave the test rig connected and watch the leds each time I boot up.

Side note: Koz319 is working on a neat program for this, but I think it is for windows only (But I may be wrong). Anyway, I wrote some logic once for my job that used the printer port for real world I/O. This project used a dos computer. I wrote the program in QBasic, which will run in DOS. If there is enough interest from DOS users, I can try to copy what Koz319 is doing for DOS.

[DaOld Man]

Turning off the monitor would certainly be a clean solution, but if you want to draw focus to the cool rotating monitor in your setup, could you have the front end play an animation while the monitor rotates before a game starts?  Like a spinning spiral, or a bunch of gears that look like they are doing the work.  The sign at the Wynn in Las Vegas has a part that moves over a huge monitor and when the movement is happening they have all kinds of animations that play with the movement to interact, it looks really cool.

I think I posted the last post while you were posting...

That sounds like a neat idea, but you would have to degauss at end of rotation, unless you use a lcd monitor.

[DaOld Man]

Ok, I have found that I cannot connect the pnp transistors base to pin 4.
Pin 4 is set high by windows on startup, why, Im not sure, may be windows is trying to que the printer through that output?
Anyway, I will be connecting the transistor to pin 7. It seems to go back low after windows loads.
Aint Windows just grand?

[DaOld Man]

I have still not received my opto isolators from ebay. I am beginning to think I may have gotten ripped.
My Radio Shack doesnt have any, so I may have to order elsewhere.

I hooked my test bread board and my H drive, power supply. and motor to a old windows 98 machine I have.

It seems to work just fine, but I would still feel better using the optos on my mame PC.
Anyway, I wrote a small DOS program that allows me to plug in "on" and "off" times to toggle the #2 printer pin on and off.
I was experimenting with motor speed control. (Pulse Width Modulation, or PWM)

I came to these conclusions:
With H drive forward input connected to Printer Port Pin #2.
I can control the speed of the motor by varying the on and off times.
But it does have its drawbacks.
First of all, the motor is being turned off and on, so it constantly jerks.
The motor is more noisy.
The H Drives power transistors got pretty hot, so I think heat sinks will be a must if you plan to use PWM.

I cannot measure the motors speed, because I dont have a tachometer, but I can clearly see a difference in speed.
I tried 1 millisecond (ms) on and 300 ms off. This seems to get a pretty slow speed.
Seems like increasing the time on makes less difference than increasing the time off.

I am planning to build a program to rotate the monitor in DOS.
I probably wont use it, since my mame machine is on a windows XP machine.
But it is letting me develop PWM, and it will be cool for those who still use DOS.
If anyone's interested please let me know.

Using your printer port for I/O is a lot easier in DOS than it is in Windows.
You dont need an external driver in DOS.

[theCoder]

I cannot measure the motors speed, because I don't have a tachometer, but I can clearly see a difference in speed.
I tried 1 millisecond (ms) on and 300 ms off. This seems to get a pretty slow speed.
Seems like increasing the time on makes less difference than increasing the time off.

1 ms seems awfully short a duration to try to drive a motor.  Especially a 1/300 duty cycle.  Are you sure you are actually getting one ms on.  The "less difference" may (??) be that the line is not outputting what you are expecting.  If you have access to one, you might put an oscilloscope on your drive line.

Glad to hear you have motion anyway.  Keep it up.

Too bad on the chips.  I usually buy my stuff from Newark.com.  Ebay is hit or miss on components. 

[DaOld Man]

You could be right on the pin not actually staying on for 1 ms, or off for 300.
I dont have an oscilloscope, so I dont really know.
Probably the best way to regulate the speed in this situation would be using a potentiometer on the motor leads, or perhaps in the H drive circuit.
I dont think I will need to regulate the speed in my setup anyway, I was just doing some research to see if it can be done, might be a good alternative to using speed reducing gears.
If the optos dont come in by the end of this week, I will place an order with a company.

[DaOld Man]

I am still waiting for my optos.
I have ordered some more stuff from allelectronics.com. I went ahead and ordered some optos from them. I just dont have a good feeling about the ebay deal, since the guy wont answer my emails.

 Edited: 01/11/08... Moved drotate.exe screen shots to this thread.

[DaOld Man]

Drotate.exe:
It is for DOS only, but you can look at it in Windows, you just wont be able to turn on outputs.
Let me know what you think.
If enough people like it, I can write it again to be Windows compatible.
(The Windows version would need the driver Koz319 recommends.)

Edited: 01/11/08... Moved drotate.exe screen shots and download file to this thread.

[DaOld Man]

I changed the following screens a little:
Screen shot #1 is now displayed if you type drotate s  at dos command prompt.
Second is printer port diagnostics (change the name a little, and added port addresses).
Third is I/O assignments.

Edited: 01/11/08... Moved drotate.exe screen shots and download file to this thread.

[DaOld Man]

I received my order form all Electronics today, and my 33 optos from ebay. Seems the post office had screwed up and been delivering my mail to the wrong box.
I will try to post some pics and prices later.
I did get some #25 chain, and a plastic sprocket, but the sprocket doesnt fit my motors shaft, so I may have to do a little rigging..

[bfauska]

I'm looking forward to seeing another implementation of the mechanics involved in this process, each one has some great features, and they usually build on all the versions done prior (Except Cornchip's, most people don't manage to imporve on his system very much.)

Bummer about your mail too, I bet you gave the ebay seller hell, I know I would have, and then I'd find my foot lodged half way down my throat.  Oh, well, at least you can edit any bad feedback and you got your stuff.

[DaOld Man]

Yeah, I agree about Cornchips setup.. Its very good.

Fortunately, I had not left feedback for the guy on ebay yet.
He never sent me an email to confirm that I had won, and he never sent me the shipping notice, and he wouldnt answer my emails.
In my last email (sent last Friday), I told him I was going to file a claim if I didnt get the item or hear from him by Tuesday. Im glad I noticed I hadnt received any bills for the month on Monday. Decided to wait and see if the order from him got screwed up by the post office.
I gave him a positive mark, but low mark on communication.
The user name is trendcomp, in case anyone else deals with him (a lot of positive comments).

Now I have 39 optos. (I ordered 6 from All Electronics)
Its always nice to have a few optos in the junk box, so Im happy.

Now I just got to find time to assemble my interface board.
Maybe this weekend..

[DaOld Man]

Ok, I got a little bit of work done on the isolator interface last night.
Here is a picture of the pc board with most parts placed on it.
I have 6 TIL119 opto isolators, relay diodes, terminal strips and status leds placed on the board.
In the picture, along the left are terminal strips for the two rotation limit switches, a SPDT auto/manual switch, and two manual rotate buttons.
On the top are two terminal strips for degauss and monitor off relays. (I havent decided yet what I want to do, so Im leaving the door open.)
Directly below those terminals are two surge diodes for the relays.
To the right of that are 4 leds. These will tell me if I am getting the signals from the printer port.
Right down the center are the 6 opto isolators.
To the right of the board are the auto/manual switch I am thinking of using, and a cherry micro switch with a roller on it. I am thinking of using this type switch for my limits.
Cost thus far:
H Drive cost: 20.65

These parts are from Allelectronics.com:
PC Board (Part # PC-4): 2.00
2-Pos. PC teminal block (TER-202) 4 X .45 each: 1.80
3-pos. PC term block (TER-203) 2 X .60 each: 1.20
Shipping : 7.00

Cost of 6 TIL-119 opto isolators: 1.50
(I ordered 33 from ebay with shipping total price = 8.39, so they cost me about .25 each)

Total thus far: $34.15

The switches, diodes, and leds were in my junk box so I dont know what they cost.
It kinda gripes me about allelectronics orders shipping cost, but I aint getting on that soap box again.
I did order more parts with that order, which I may use on this project if I do, I will add the cost of those in later. The shipping is already covered if I do use them.

[DaOld Man]

Finished the isolator today.
I originally used 1K resistors to pull the input to ground, but this wasnt enough. I had to go back and solder 2 K ohm resistors in parallel with the 1 Ks. This brought the resistance down to about 670 ohms.
Note to KOZ319: If you can make your program look for an input going low instead of going high, it will make the circuit a lot easier.
Here are some pics..
1st pic is board fully assembled. (Before I added the 2 K resistors).
2nd pic is iso-board with H drive attached (riding piggy back).
3rd pic is isoboard connected to motor and power supply and dos computer.
Now I can start to concentrate on the rotating mechanics.

[DaOld Man]

Here is a crude picture of how everything hooks up. (I made this to remind me when I hook this up later. Probably much much later..)

[theCoder]

One possible reason why you have not had many downloads of the code is there probably is not that many people building a rotating monitor systems at this time.  Also, "DOS only" may be an issue.  Over time, you'll probably get plenty of hits.

Great job on documenting the project.  This should help someone else out down the road.

[csa3d]

One possible reason why you have not had many downloads of the code is there probably is not that many people building a rotating monitor systems at this time.  Also, "DOS only" may be an issue.  Over time, you'll probably get plenty of hits.

Great job on documenting the project.  This should help someone else out down the road.

I agree with both statements.  I can tell you that I'm following every update in this thread on a surface level, and am sure if/when I get around to motorizing like I'd like to, this thread will become invaluable.  Thanks for being as detailed as you have been.

-csa

[DaOld Man]

Thanks for the kind comments.
One of the power transistors failed on my H Drive. I was testing my circuit on the DOS machine. The drive wasnt being told to come on, but I noticed the motor turned about a quarter turn then stopped. Then I noticed one of the transistors got very hot, then the AT power supply shut down. I tried to shut it off when I noticed the transistor was hot, but I guess I wasnt fast enough.
Now whenever I hook power to the H drive it shorts out the power supply.
I think one of the transistors shorted, and took out it's opposite mate.
I guess Im glad it did it now instead of after I had in mounted in the cab and using it.
I plan to tear it down sometime today and test the transistors. I am thinking I may have stressed the transistors when I was playing around with PWM on them. They got pretty warm then. (See a previous post.)
I also am taking the H Drive inputs to 12 VDC + through 5 K ohm resistors. I may need to use much higher resistors. (I plan to experiment with the drive when I fix it to see if I can use much higher resistors.)
Now I need to order more transistors, or I am thinking of building a drive from two relays.
The relay drive could be a demonstration to those wanting to go that route.
The relays would be more expensive than replacement transistors, and I "just like" the H drive. But relays would be much more rugged and since I dont plan on using speed control, the PWM wont be an issue.

[javeryh]

One possible reason why you have not had many downloads of the code is there probably is not that many people building a rotating monitor systems at this time.  Also, "DOS only" may be an issue.  Over time, you'll probably get plenty of hits.

Great job on documenting the project.  This should help someone else out down the road.

I agree with both statements.  I can tell you that I'm following every update in this thread on a surface level, and am sure if/when I get around to motorizing like I'd like to, this thread will become invaluable.  Thanks for being as detailed as you have been.

-csa

Same here.  I'm definitely going to try this with my "Wife-Friendly Arcade" but I'm a ways off from actually attempting it.  I have been following the progress here and I will be asking a ton of questions when I actually start.  Thanks for keeping such a detailed account of your progress...   

[DaOld Man]

I had to loose the 4 leds on the right side of the board. Seems these were dropping the voltage to the opto isolators and making the circuit do some crazy things. I think it was oscillating, outputs turning on and off very fast. This might have been what fried my H drives transistors.
With the leds out, the circuit appears to be a lot more stable.
Also I found a bug in my drotate.exe program. Its not reading the inputs correctly.
So Im removing the download from here, will re-post it later when I have time to figure out the bug in the program.
Now I need to order some more transistors for the H drive..
Man this project is going to wind up costing me more than I got in the whole arcade cab (LOL), Well, it's no where near that right now.
Ive got two 3PDT 12 volt relays in my junk box, maybe I will throw together a relay drive.
I know the opto isolators will turn on the relays, I have already tested that.
So, I may have some new pics soon! (Wish me luck, everything I touch lately has let smoke out of something.)

[DaOld Man]

I threw together a relay drive based on a schematic I posted in a different thread.
If anyone wants to do this, let me know, I will post the schematic here.
I mounted two 12 VDC 3PDT relays on a piece of mdf board. (This is just a quick test job.)
First pic shows the relay drive connected to a motor. The red wire is 12 VDC pos supply, black is 12 VDC negative supply.
Brown wire is rotate clockwise signal, white wire is rotate counter clockwise signal.
I placed the H drive beside it to give you a size comparison.

I hooked the relay drive to the AT power supply, the motor, and the opto isolator board.
It works as expected.
Using Drotate.exe on my dos machine to test it, the motor rotated as it should have.
I didnt wire a braking circuit into this drive, I dont think I need it.
The only complaint I have is the space this drive will take compared to the H drive.
But if you can wire up a control panel, you can wire this type drive.

The second picture is showing the relays removed and the wires between the two sockets.
(Sorry about the mess, I was in a hurry and this was just a test job.)

Also I will post the schematic wiring diagram upon request.

[csa3d]

I threw together a relay drive based on a schematic I posted in a different thread.
If anyone wants to do this, let me know, I will post the schematic here.

Nice!  Can you URL link the other thread here at least for documentary sake

Code: [Select]

[url=http://www.hyperLinkGoesHere.html]Click here to go there text![/url]

[DaOld Man]

Sorry bout that..
Here is a link to the thread that I first posted my drawing for the relay drive..

Click here

Please note that the original drawings are different from what I just threw together.
The CWR and CCWR relays are the same, but Im using the opto isolator interface board to turn them on. Plus I didnt use a braking resistor on this.

I just ordered some transistors form mouser today. Hopefully I will get my H drive repaired early next week. I went ahead and ordered some bolt-on heat sinks for the transistors.
I tested the transistors and Q2 and Q4 were shorted. All other parts look good.
Not sure what happened, but Im going to have a fear in the back of my mind now..
I ordered enough transistors today to build another H drive. I may need a spare, just in case.
I think if I hadnt already spent the bucks on the H drive, I would just go with the relays.
I also think that if someone wants to build the relay drive, you can use solid state relays to interface the big relays to the printer port.
Might get pretty expensive, based on H drive and isolator circuits, but it would be a lot simpler for those who dont want to get in to a different hobby.

[DaOld Man]

I have been playing around with mala on my desktop PC.
I have the relay drive/isolator board plugged into my PC.
Im using the mala plugin that KOZ319 wrote.
It works great, except the I dont think the time limit will be enough. I cant find anyway to change that on the plugin. (Hint Hint KOZ319).

I have been working on a program in VB6 that is very similar to my drotate.exe program.
I think it will be nice to be able to assign the inputs and outputs you want to use, plus be able to vary the time limits.
I just dont know how I would make this into a mala plugin.
Koz319, it would be neat if your plugin had a small text file that one could change these settings in. (Similar to most ini files, IE glaunch.cfg) Please let me know if you are working on that for your plugin, if so I wont need to put any more time on mine.
An application should allow the user to select rotate time limits (in both directions), whether or not to turn off monitor during rotation, and whether or not to degauss the monitor. Plus, if you turn off the monitor during rotation, but still need to degauss it when it comes back on, an optional pause time needs to be deployed, to allow time for the monitor to power up before degaussing.

I plan to use a normally closed contact on a relay to turn off the monitor.
This has two advantages. It allows the program to output a signal only when the monitor needs to turn off. And if something fails, the monitor will be on all the time, not off.
(Fail safe so you can still play certain games until you find time to fix the problem).

[koz319]

Im using the mala plugin that KOZ319 wrote.
It works great, except the I dont think the time limit will be enough. I cant find anyway to change that on the plugin. (Hint Hint KOZ319).

I think it will be nice to be able to assign the inputs and outputs you want to use, plus be able to vary the time limits.
Koz319, it would be neat if your plugin had a small text file that one could change these settings in. (Similar to most ini files, IE glaunch.cfg) Please let me know if you are working on that for your plugin, if so I wont need to put any more time on mine.

I actually have already updated the plugin  (and the cmd line prg) to support a cfg file.  It allows you to set all the timeouts, degauss, pin assignments, trigger on hi or lo etc.  I was fiddling around with basic PWM for speed control as well.   I'll post it when I get home tonight - I might leave out the PWM for now because I really haven't had a chance to test it.

I'll post it on my site as well.

Thanks!

Koz

[DaOld Man]

That sounds great Koz319!!
I am going to modify my isolator board to bring inputs to ground.
I plan to use a 100 ohm resistor to tie the input to ground through the opto isolator.
Please post your plugin as soon as you can. I am interested in the command line version too. This might be what GLaunch users need. (I wont need the PWM version).

I went by Radio Shack today, and they have a 10 amp relay which is DPDT for about 10 bucks. The one I looked at comes with a socket too.
A DPDT relay will work for the relay drive, but you wont be able to use a braking resistor.
So for around 25-35 bucks (including cost of opto isolators, resistors, and printer cable), you can build a relay drive.
I started to go ahead and buy the relays and start a new thread showing how to build a relay drive using those relays, but I dont really need it, and I didnt want to throw the money away.
But if someone would like to pay me back for what I have in it, I can do it, and whoever buys it will have a ready made drive.
I may go ahead and make the thread anyway, using information on the relays from the radio shack website. (Warning... more crappy paint pictures ahead! )

[DaOld Man]

OK, here is a very simple drawing I threw together using two radio shack DPDT relays.
Model: 275-218  |  Catalog #: 275-218
These relays have solder lugs on them, so you can solder directly to the relay, but I highly suggest you use a socket. Attach your wires to the socket, then if something happens to the relay 5 years down the road, just unplug and plug in a new one.
Heres the socket: Model: 275-220  |  Catalog #: 275-220
(On the website, I couldnt find the relay/socket combo they have at my store.)
Anyway, the picture is not as complicated as it may first appear.
The drawing on top is the schematic, with pin numbers that are on the relays. (As best as I can tell from the picture anyway).
The bottom part shows the relays wired in real life. I used different colors for the wires to help you distinguish between them.
I highly suggest you use the diodes D1 and D2. These can be just about any general purpose 1 amp diodes (Radio Shack Model: 1N4003  |  Catalog #: 276-1102)
I am not showing the circuit that turns these relays on, but if you touch the CCW signal wire to power supply + the motor will turn CCW (if not reverse the motor leads). If you touch the CW signal wire to + the motor will turn in opposite direction.
Touch both signal wires to + and the motor does nothing.
You can use a SPDT switch or pushbuttons to turn these on.
You can also interface these to your printer port, but not directly.
They will need to be turned on through opto isolators, or transistors. If you go this route then diodes D1 and D2 are a must.
Or you could use a SPST N.O. solid state relay. It will take two. The printer port signal turns on the solid state relay, and the solid state relay turns on CWR or CCWR.

[DaOld Man]

I hope everyones having a great weekend.
I got the new parts for my H Drive from mouser.com yesterday. That was super fast shipping.
I plan to repair the H Drive tomorrow afternoon. The place that pays me to show up required that I show up this weekend, 12 hours yesterday and 12 hours today.
Once I get the H drive back online, I plan to throughly test it.
Then I can begin to decide what mechanism I am going to use to transfer motion from motor to monitor.
There are a lot of good ideas on this forum. I am studying them.
Also, I plan on using a 21" CRT monitor, but Im not 100% sure that I have enough room in my cabinet.
I have a 19" CRT I can fall back on if I have to.
I plan to place my CRT on my bar (since its too cold outside now) and play around with it. Turn it, measure it, hook it to a spare PC and see how it all feels.
I will try to post more pictures soon.

[DaOld Man]

Here is drotate.exe in zipped form.
I think I got all the bugs worked out.
I also added an option on the I/O section.
You can choose whether to look for inputs going high or low. (Thanks for the idea, Koz319).
Remember, you might be able to look at in windows, but it will only act right with the printer port in DOS.
Please let me know if you find any bugs or discrepancies..

Edited: 01/11/08... Moved drotate.exe screen shots and download file to this thread.

[DaOld Man]

I installed the two transistors on my H drive.
Everything seemed to be working good, until I tried to turn on both directions at once. (This should just brake the motor.)
The other two transistors (not the ones I just changed), got extremely hot and shorted out.
I am just about ready to go with the relay drives. This part of the project is taking a lot longer than I had planned.
Anyone got any ideas as to what is going on with my H drive?
I double checked my wiring, it looks good.

[DaOld Man]

Ok, I have thought about this until my head hurts. I think I will just use the relays for the drive.
I already have everything I need, and they work perfectly with my already built isolator board.
I plan to post the finished drawing of my isolator board (I made some modifications from the original).
I also plan to talk to a friend of mine who is an electrical engineer about the H drive.
Maybe he can tell me where Im going wrong. But I decided that I just cant take the risk of this thing failing on me during one of my "show off the arcade" parties. (I think you all know what I mean.)
So, I plan to assemble the relays and opto board on a block of wood and call this section finished. So then I can move on to the hard part, making the monitor turn..
(More pics soon, I promise)

[DaOld Man]

Ok, I talked to my engineer friend and he thought that the transistors definitely need to be heat sinked.
Also, he said since the circuit was designed for logic signals (0-5 VDC), that the 12 volts from my isolator board may be too much.

Ok, so here is my plan now:
I am going to rebuild the drive from the extra parts I bought.
I am also going to use 5 vdc from the AT power supply to power my isolator board. I have already tested it and I think it will work on 5 volts. (I was worried about the two isolators switching the inputs to the computer, since I calculated the resistors at 12 volts.)
The only draw back will be having to use 5 VDC relays for the monitor on/off instead of the 12 volt ones I already have.
My new H Drive will have heat sinks. (My common sense told me to use them the first time, but its not the first time I didnt listen to common sense.)

If this one fails, Im going with the relays and thats that!

With Christmas coming up Im not going to have much time to work on this project, so updates may be a little slow.
I would like to hear if anyone else is working on a similar project, and if anyone is using my relay circuit. I know people are working on rotating the monitor, but are you working out the electronics like I am at this stage?

[DaOld Man]

Hope everyone had a wonderful Christmas and a good New Years eve.

I am finally updating this thread.
I have built another H drive. It is the same as the first one, except I added some pretty hefty heat sinks to the power transistors. I also changed the isolator board a bit.
I added a dual terminal for the 5 VDC power. I also re-wired the isolator board to look for the limit switches pulling the inputs to low.
I hooked it to my dos machine and tested it using drotate.exe.
It all looks good now.
First pic is the H drive mounted piggy back to the isolator board. Its connected to an old AT power supply and a motor.
Second pic is my dos machine.
Next step: rig up the 21" monitor I plan to use and play around with it a bit.
This is my plan:
The first machine I built was called "Benny B's Arcade".
It has a 17" crt monitor in it now.
I plan to redo this arcade. (Add trackball, put on heavier plexi glass, and a few more things).
I plan to mount the 21" monitor in Benny B's, if it will fit. I am still not sure it will fit.
I plan to start a new thread on the progress I make re-doing Benny B's Arcade.
But I also plan to keep this thread going until I am satisfied I have a rotating monitor setup finished.

[DaOld Man]

Here is an updated drawing for the isolator board.
I didnt change R8 and R9 when I changed supply volts from 12 to 5. It appears to be working, but if you build this same circuit and use a 5 volt supply, I suggest you change these two resistors to 100 ohm.

[DaOld Man]

Here is modified hook up diagram.

[DaOld Man]

Here is a picture of how my drive will hook up to everything. I could only find one pushbutton and one roller limit switch, so i did a little copy and paste. I may not use those switches anyway, but it should give you an idea how simple this will be to hook up.

[DaOld Man]

And here a couple of close up pics of the drive. (first is not good quality).

[Jimbo]

Looking good!

My own rotating circuit is kind of stuck at the moment. I have a half-finished circuit that I need to add the speed controller for the drill motor then actually get round to mounting the thing and testing it out!  Its also a bummer for me that the Hantarex Polo monitor I'm using only degausses on cold starts.  I've emailed them to get more info on whether its possible to interface to the neckboard to degauss using a signal... here's hoping!

How are you actually mounting your monitor btw?

 

[DaOld Man]

Thank you.

Do you plan to control the speed of the drill motor, or just the direction. Direction should be pretty easy, using relays.
If you need some help, I would be glad to help, if I can.
You can also use a relay to turn off the monitor while its rotating, when the rotate finishes, the relay will turn the monitor back on, then if it auto degausses that should work..

About the hardware to actual position the monitor:
I havent started on that yet. My garage is not heated, so most work like that will be put on hold until I can catch some warm days when I dont have to work.
But I plan to copy most of the other methods people use, and that is, cut a circle out of mdf or ply, then mount the monitor to that.
I plan to remove the monitor from its case and mount it to the wood with 4 bolts.
(Check out the attached picture of the way I mounted my last one, which does not rotate.)
Im not going into specifics yet, because I want to give links to threads of the ideas I will use, to give the persons the the rightful credit. I will give those links when I implement the ideas.

Can you post the make/model of your drill, and a drawing of how you are wiring it? Or pm me and I will give you my email, if youd rather mail it to me. (Thats if I can help.)

Anyway, good luck, and keep us all posted...

[DaOld Man]

I hooked everything up to the 21" Dell trinitron I was planning to use. (On the back it has "Ultrascan P991").
With the screen turned vertical, mspacman is huge!
Anyway, the screen degausses each time the monitor is turned on, so the degaussing shouldnt be an issue, since I plan to turn off the monitor while rotating it.
I do see a problem with the monitor. It has very thin lines, white in color, first line running diagonally from upper right corner to the left, dropping about 1/2 inch. The next line is about 1 inch below the first, following the same pattern. More lines follow each spaced about an inch apart, filling the height of the screen.
These lines are not real noticeable, but I dont like it.
On Zaxxon, the ship kinda shifts shape when it passes through one of the lines.

Anyone know what could be causing these lines?