New Drum monitor build

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Postby Harry Dalek » Sat Feb 04, 2012 9:46 pm

Ok heres where i am at today ...spent yesterday doing the second stepper motor circuit and today i worked out my panel ,i forgot about the audio jack but might stick that in the back.

The panel part was a bit of pain mainly because having to take it off to do and solder the controls for it .

I have the main things i want there both stepper speed direction controls and picture ...that should do for now .

Now i can start connecting to the power and the stepper board .

A little closer :)
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Sun Feb 05, 2012 1:21 pm

Today i hooked up the power supply to the stepper board and motors and gave it a spin :wink:

First time i have checked my my second stepper motor board as well ,i changed it a bit to the first in 2 ways first i have PWM control of the clock and using a uln2803 over the smaller 2003 the first is fine for the small drum but wanted to see if i could ramp up the speed with this driver and the PWM.

Seems to have worked ,need to change this as speed increases.
i know there are feed back iC's and circuits that do this but mines a manual test for a start ...i suppose using a lDR fork idea feeding back to the monostable to adjust the pulse width might work in a automatic way ...all i know at the moment is changing the pulse width sure helps the motor.

Running both off same 5 volt supply circuits and all so heres a little short video till i wipe my camera card...

Back to work :shock:
Attachments
Picture 278.avi
Heres my motors running not really top speed as i was just mucking around for a start .
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Tue Feb 07, 2012 11:27 pm

Been wiring the panel to the stepper board so thats done ,i had switches and controls on board for testing .

I have 2 direction control for both motors start and speed control on the panel .

Thinking about the diffuser and light now ...diffuser i will more than likely do what i did last time and just cut some strips of plastic milky plastic milk container and glue those over the slits of the inner drum worked rather well on the CDM .

Lighting i need as much as i can do ,i have enough 1 watt luxeons to repeat what i did and see how it gos but i think this one would need more due to the thinner lines .

So next doing a luxeon array and do a light test next few days .
Attachments
Picture 291.jpg
Board all wired up now
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Picture 292.jpg
using my very old camera its in B/w this time ; )
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Thu Feb 09, 2012 2:41 pm

Today i finished my luxeon array ,i am using 9 watts this time....also finished the diffuser ,went with the milk container plastic 2 layers in two strips to cover 3 slits either side of the drum that will defuse the light well.

You do loose a little light going 2 layers but any case i think the idea of using the drum as a diffuser works good in a lack of space between the drum and luxeons a rotating diffuser ...last time i just cut out a strip for each slit this idea is easier.

I did a quick look at how the line scan would go with the slanted slits and it works you see these things in your head but nice to see it for real !

I will do a video when i work out where my camera chargers gone !
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Sat Feb 11, 2012 10:53 pm

I had finished my club light modulation circuit yesterday and did some testing today .

No great results today to show apart from the scanning which you might find interesting so posting a few videos and pictures .

My main stepper motor on the main drum is getting there but speed is still to slow for the main drum and being 16 lines i am pushing it for 1500rpm and i know i might be on a loosing battle ....but i am still playing around with my timers speed with different caps .

So i will play around a bit more see how i go ,i am pretty sure with a 32 line drum it would make it workable looks like it can do 750rpm.

Takes a bit of evolution of the thing before i can scratch build something into a workable tv but thats the fun of it nothing good is easy :roll:
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Picture 341.jpg
second shorter look at earlier todays drum test
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Picture 315(1).avi
This was the first video i did the steppers are still slow got it a bit better since this video.
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Picture 351.avi
This is just a hand turn of the drum to show how the raster dot scans with the slanted line slits
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Harry Dalek » Sun Feb 12, 2012 5:22 pm

Testing both my drum monitors against each other to see the speed difference between the two ...it is still short of 750rpm ,i was thinking it was close but nope !

So a little back tracking and rethinking i have added a dc motor to the mix i am going to see how it gos with the motor attached to the large drum and stepper motor but for the start see if it gets the speed which it should then i will try using the stepper for braking ...which should be interesting ...

If it doesn't work make it work i say :roll:
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The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Sun Feb 12, 2012 6:34 pm

I like the idea of the extra DC motor - will be very interested in how it goes.
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Postby Harry Dalek » Sun Feb 12, 2012 8:34 pm

gary wrote:I like the idea of the extra DC motor - will be very interested in how it goes.


Hi Gary i was hoping to just do it with the stepper but i suppose if i went with a larger pulley wheel at the stepper side i could get there or a better stepper motor but want to speed things up .

I was thinking as we talked about it while back this idea might be worth a go if any thing i know i should have the speed with the dc motor on its own but its got the pulley system as well 3 times or so the normal motor speed and there must be some resistance as the stepper is run at that speed powered up and adjusted worth a try ..with the help of the dc motor does clogging not happen mmmm we will see ...

Again on the stepper feeding voltage back to the driver circuit is my only worry but i will give it a go .

Might be a few days now as i am back at work tomorrow .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Tue Feb 14, 2012 8:46 pm

Because of resonances there are "hot spots" in the speed characteristics of a stepper that prevent it reaching a particular speed. It may be possible to bring a stepper up to any particular speed (with, say, a DC motor) and for it to run quite happily at that speed.

None-the-less, as I have hitherto mentioned, running the stepper at a higher voltage with a suitable current limiting resistor is always an option you could try.
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Postby Harry Dalek » Tue Feb 14, 2012 9:28 pm

gary wrote:Because of resonances there are "hot spots" in the speed characteristics of a stepper that prevent it reaching a particular speed. It may be possible to bring a stepper up to any particular speed (with, say, a DC motor) and for it to run quite happily at that speed.

None-the-less, as I have hitherto mentioned, running the stepper at a higher voltage with a suitable current limiting resistor is always an option you could try.


Hi Gary yes thinking about the Dc helps the stepper and the stepper controls the Dc bit of a loop happening .

I am keen to see what happens i will get suck into it tomorrow .

I have a current limiting resistor on the large drums stepper ...but i have tried running both uln ic's on a higher voltage nothing more than 12v but have found it kills the ic out right i have found also even at 5 volts without a resistor of a few ohms to the stepper they can fail in time more so the uln2003 than uln2803....thank goodness for ic sockets ! perhaps i should of went with MOSFETS.
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Tue Feb 14, 2012 11:36 pm

harry dalek wrote:perhaps i should of went with MOSFETS.


Considering you want something along the lines of 10 times the stepper rated voltage I think that's a big yep.

EDIT: OTOH I don't think you are exceeding the rated voltage (of the outputs) - are you SURE you are not exceeding the devices current carrying capacity? (500mA) In other words is your current limiting resistor large enough?

Can you post your circuit including the resistance of the stepper motor windings (or the specs of the stepper if you have them)?
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Postby Harry Dalek » Wed Feb 15, 2012 3:22 pm

gary wrote:
harry dalek wrote:perhaps i should of went with MOSFETS.


Considering you want something along the lines of 10 times the stepper rated voltage I think that's a big yep.

EDIT: OTOH I don't think you are exceeding the rated voltage (of the outputs) - are you SURE you are not exceeding the devices current carrying capacity? (500mA) In other words is your current limiting resistor large enough?

Can you post your circuit including the resistance of the stepper motor windings (or the specs of the stepper if you have them)?


Gary i will look for the circuits i used and what i changed and post ....

I was only using 10 ohm 1/4 WATT RESISTOR between the voltage + and to the stepper sounds like i got that wrong ,i didn't worry as it didn't heat up .....ulns are rated for 12 volts using these circuits they didn't use it so at the start i didn't worry about till i put the voltage up to 12 voltages to see and killed the driver every time .

On both circuits the main change is i only have manual switch controls to pins 9 and 10 to ground of the 74194 to start and control direction of the steppers .

i don't use the 7474 or the transistors for this part of the circuit...

My clock gos to a monostable with pulse width control then to the 74194 in the uln2803 circuit

My steppers are the old floppy drive types as you were saying a while back ,the stepper motor windings the small drum uln2003 stepper one is 8.3 ohm and the large drum stepper is 4.2 ohm per winding
I can't see whats written on the steppers now its all out of view.

Going to fire up the Dc motor tonight see what speeds i get .
Attachments
StepperBasic.jpg
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Rangkaian Unipolar Stepper Motor Driver.jpg
Rangkaian Unipolar Stepper Motor Driver.jpg (57.57 KiB) Viewed 7129 times
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby gary » Wed Feb 15, 2012 4:06 pm

Harry,

stepper 1:

I = V/R = 12/(10+8.3) = 0.66 amps = pfzzzttt!

stepper 2:

I = V/R = 12/(10+4.2) = 0.85 amps = pfzzzttt!

Actually, the ULN2003 are rated for 50V (according to my data sheet) and you would probably want to get the voltage somewhere up towards that to get the speed you are after. You just have to make sure the series resistor keeps the current below .5 amps (say .4 amps), and is of a power rating large enough to dissipate the heat.

For instance:

Stepper 1:
for 12V R = V/I - Rs = 12/.4 - 8.3 = 22 ohms (5 watts)
for 40V R = V/I - Rs = 40/.4 - 8.3 = 92 ohms (15 watts)
Stepper 2:
for 12V R = V/I - Rs = 12/.4 - 4.2 = 26 ohms (5 watts)
for 40V R = V/I - Rs = 40/.4 - 4.2 = 96 ohms (16 watts)
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Postby gary » Wed Feb 15, 2012 4:52 pm

Oh, and good luck with the DC motor, I really think this should work and is something I've been meaning to get around to - it is very similar to Baird's sonic wheel in principle and so I will be keen to see how it goes.

BTW, I still have so much of my NBTV stuff packed away (since my move) I can't do any practical NBTV work at the moment so I am using you vicariously at the moment, I hope you don't mind ;-)
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Postby Harry Dalek » Wed Feb 15, 2012 6:39 pm

gary wrote:Harry,

stepper 1:

I = V/R = 12/(10+8.3) = 0.66 amps = pfzzzttt!

stepper 2:

I = V/R = 12/(10+4.2) = 0.85 amps = pfzzzttt!

Actually, the ULN2003 are rated for 50V (according to my data sheet) and you would probably want to get the voltage somewhere up towards that to get the speed you are after. You just have to make sure the series resistor keeps the current below .5 amps (say .4 amps), and is of a power rating large enough to dissipate the heat.

For instance:

Stepper 1:
for 12V R = V/I - Rs = 12/.4 - 8.3 = 22 ohms (5 watts)
for 40V R = V/I - Rs = 40/.4 - 8.3 = 92 ohms (15 watts)
Stepper 2:
for 12V R = V/I - Rs = 12/.4 - 4.2 = 26 ohms (5 watts)
for 40V R = V/I - Rs = 40/.4 - 4.2 = 96 ohms (16 watts)



Hi Gary Thanks for the maths i am not good at that part or lazy @Q !
I understood your instructions about the voltage i just didn't understand why the Drivers failed at 12 volts as i recall it didn't move the stepper well....... and after a few seconds nothing readjusting it back to 5 volts it was obvious that driver would never drive a stepper again :roll:

It got me beat why its rated at higher voltage the thing failed same gos for the 2803 .

And as i said with out the resistor i had a few faulty drivers even at 5 volts so i was thinking the stepper was feeding to much voltage back to the driver.....or may be i was sold duds .

i have lots of 2003s so those dieing is no great loss i would like to would it out ,i will try your resistors since you say it should work .

Gary its one resistor for the stepper yes not a resistor for each coil ? i did it wrong if so .

Yes hopeful to see the Dc and stepper experiment work when the kids go to bed i will get stuck into it .

Yes also ask away the stepper help is great i need to learn more so no problems ...no good when you can't do the hobby !
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Harry Dalek
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