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ARDUINO & DAC for XY projector

henny

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its more the design of the correction amplifiers i need
 



camvo

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Have a look at post #5 at the beginning of this thread.

Is that enough?.
 

Lordasriell

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hi camvo, hello everybody.
i follow your thread for a while now, and i think your due shield, camvo can run a laser 3d printer. i have two galvos (x, and y), ordered 2 years ago, and your shield seems to be the easier way to run them with an arduino and read sliced parts of printed objects.

my question is :have you a list of component you used for ?

you have done a great job with this, i'm impress ^^

thanks, have a good day ! ( sorry for my english, i'm french...)
 

camvo

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Hi Lordasriell,

Have a look at post#5 and #86.

It is not enough/clear?
 

Multimode

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Hi Camvo,

It's been a while, hope you're OK and the project is going well :)

ATB
MM
 

camvo

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Hi Multimode!

I am fine thank you. I hope you are fine too.

I have made an enhancement to the board.
It has become a kind of an interactive DAC.
You can "play" it like an instrument.
So instead of THE dac PLAYING a fixed routine/program, you can switch between paterns, change speed size, color and rotation.

I added bluetooth so you can operate it with your smart phone while you are in the audience :D

I have made the pcb-s, just did not have the time to assemble the lot and test it.

CHEEEEEERS!!!
 

Lordasriell

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oh yeah, i haven't seen components menu the first time i opened designspark, thanks to you camvo, i'll keep you informed if it works for me ^^

ps: what do you mean by "ra_pre" ? i can't identify the component by myself :x
 
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camvo

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RA-PRE???

Where do you see that?

I made the PCB with designspark.

Do you want me to send you the PCB?

See below attachment.
 

Attachments

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Lordasriell

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i opened your file .pcb with designsparks yes, but in the component list, there is one called "ra_pre" in places of gain and offset
 

camvo

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Ah now I see what you mean. The components properties.

It is a potentiometer 10k for print mounting. Laying down.
 

Hairy

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@ Laserlightguy

I am not exactly sure what you mean by pincushion.
Pincushion distortion, difficult to describe, but the outer corners of a projected square will distort due to the angel / distance..... errr this might be better:D
Distortion (optics) - Wikipedia, the free encyclopedia

For small deflection angles the effect is not very visible.
For marking / size critical applications, the system will compensate for the error.
camvo,

First, just want to say that you are awesome. This thread is like :san: read my wish list and missed all the :scowl: things I'd done all year. :angel:

Regarding the distortions, I thought I would suggest a simple reverse-interpolation way of correcting for any problems, whether they are in your galvo or from projection effects or from the surface you're hitting.

Just have your projector output a dot array, and use a high-resolution camera or even webcam to read that into your computer. Now you have the exact points that are output when you input those dots. You then interpolate to what you want based on what you got.

In other words, let's say you output a (1.000,1.000) and actually got a (1.008,1.005). Well, now you know you should really send (1/1.008, 1/1.005) to get (1.000,1.000).

You make a whole array of those coordinate pairs and you can map backwards using the closest point, or interpolate between the two (or four) closest points.

It's a fairly straightforward image-processing algorithm, and you may even be able to find code to do it in some of the freeware out there. So, next time you are in Belgium projecting stuff on the Atomium, you can do a mapping, get the reverse-mapping, and make everything come out looking like you are projecting on a flat screen, at least from the viewpoint from the laser. :D
 

camvo

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Thanks Hairy,

I will keep it to simple beam animations. For now....
 

trawen

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Thanks Hairy,

I will keep it to simple beam animations. For now....
Hello camvo!

I have a laser with ILDA input.

I assembled from your circuit 5 post and connected to the Arduino.

However, it works very strange, for the test I give to the DAC value 1000-2000-3000-4000 and get voltage 0.8, 1.7, 2.5, 3.6 volts.
(voltage Arduino 3.6 volts)

However, the output of your circuit I get a 1, 5, 6.5, 6.5 volts. As seen lacking in value between 1 and 5 volts. How is that possible?

Trimming resistors have not helped.

Perhaps the fact that instead of 12 volts I apply 9 volts?
(I take them out of the laser)

And that is sad in a laser galvanometer does not respond (not moving)

I tried to connect to other lasers, it has the power supply voltage V 15/-15 and with output voltage of the operational amplifier is obtained no clear voltage (0.2 V 0.7 etc)
 

camvo

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Hi Trawen,


Which pcb did you make?

The one from post #136?

If only one galvo moves, change the TL082. These things sometimes brake down for no appearant reason.

Is the power supply section correct?

Did you fit the shield correctly to Arduino DUE?
If the pin is one off, then only 1 DAC is connected.

You should start with both 10k trimpots closed.
Open the GAIN-pot a bit and then use the OFFSET-pot to get a symetrical Voltage.
 

trawen

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Hi Trawen,
Which pcb did you make?
The one from post #136?
If only one galvo moves, change the TL082. These things sometimes brake down for no appearant reason.
Is the power supply section correct?
Did you fit the shield correctly to Arduino DUE?
If the pin is one off, then only 1 DAC is connected.
You should start with both 10k trimpots closed.
Open the GAIN-pot a bit and then use the OFFSET-pot to get a symetrical Voltage.
Oh! Now I downloaded your PCB and I see that you are generating +/- 12volt.
And I took on a power supply of the laser. Maybe that's the problem.

Tomorrow I'll buy 7912 and 7812 and will try to copy your PCB.

Thank you.
 
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trawen

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Camvo, please tell me the name of the item on the input of the circuit?
RC3, RC4 - this diode? What denomination? I can not see on the photo.

You have to input AC or DC voltage?
 
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