Help with White Laser

GSS · Nov 3, 2016

Alaskan said:
Myself, I am not quite sure what you are asking, for a green laser recommendation?

Very nice RB astro, thank you for the photo's, all on topic, so I don't see a high jack here. The colors are very nice, I see you made different combinations, nice. I have a request kind sir, could you please take some night shots of the beam for us, maybe even a sky beam shot if willing to do that?

Ditto

kind sir...

Dog · Nov 3, 2016

I just want to make a white laser with adjustable modules. Is this possible for $80? I already have the batteries and mirrors.

RB astro · Nov 4, 2016

Alaskan said:
Very nice RB astro, thank you for the photo's, all on topic, so I don't see a high jack here. The colors are very nice, I see you made different combinations, nice. I have a request kind sir, could you please take some night shots of the beam for us, maybe even a sky beam shot if willing to do that?

GSS said:
Ditto kind sir...

I will try and get a nice sky shot for you.
Just give me a few days, I'm not feeling too well at the moment, I'm recovering from a migraine attack so I'll be taking it easy for a while.

My eBay package of 10k Pot sliders arrived so what I might do is coble together a breadboard with three sliders to make it easier to adjust.
I just have to work out a basic voltage divider circuit for each channel.

I'll see what I can do.

:beer:

Chrisbee · Nov 4, 2016

Dog said:
I just want to make a white laser with adjustable modules. Is this possible for $80? I already have the batteries and mirrors.

I'm still not quite sure what you want...
When you say "adjustable", are you trying to have it so you can adjust it on the fly to change the color output? Or "adjustable" so you can do an initial tune for a white balance, then leave it? If it's the ladder, any correct output range, non-fixed driver will work.

Personally, I don't think you can do what you want with only $80. Especially if you want to be able to adjust output on the fly.
You say you have the mirrors, but what about the adjustable mirror mounts? A good set of those will easily eat half of your budget.

Alaskan · Nov 4, 2016

Here is one of those cheap China ebay units

400mW White Laser Beam/TTL RGB Laser Light/Combined by 532nm+650nm+450nm Laser.

diachi · Nov 4, 2016

RB astro said:
I will try and get a nice sky shot for you.
Just give me a few days, I'm not feeling too well at the moment, I'm recovering from a migraine attack so I'll be taking it easy for a while.

My eBay package of 10k Pot sliders arrived so what I might do is coble together a breadboard with three sliders to make it easier to adjust.
I just have to work out a basic voltage divider circuit for each channel.

I'll see what I can do.

:beer:

If the driver is 5V analogue modulation in all you need to do is connect one pin to 5V, the wiper to the Mod+ and the last pin to Mod- and GND. Fairly straight forward

RB astro · Nov 4, 2016

diachi said:
If the driver is 5V analogue modulation in all you need to do is connect one pin to 5V, the wiper to the Mod+ and the last pin to Mod- and GND. Fairly straight forward

Oh, fantastic, thank you so much for that, I was hoping that it would be that simple but I hadn't done any testing on it yet so I assumed I needed a voltage divider.
As I said its been many decades since I played around with this stuff.

My deepest gratitude to you diachi for the info.
It may seem simple but it's a big help to me.

Cheers
:beer:

diachi · Nov 4, 2016

RB astro said:
Oh, fantastic, thank you so much for that, I was hoping that it would be that simple but I hadn't done any testing on it yet so I assumed I needed a voltage divider.
As I said its been many decades since I played around with this stuff.

My deepest gratitude to you diachi for the info.
It may seem simple but it's a big help to me.

Cheers
:beer:

No problem!

Set up that way a potentiometer is actually a voltage divider, just a variable one.

Dog · Nov 4, 2016

Do you know if that 400mw white eBay laser have individual modules that I can adjust the output for?

diachi · Nov 4, 2016

Dog said:
Do you know if that 400mw white eBay laser have individual modules that I can adjust the output for?

It'll have individual modules inside, yes. It looks like they are adjustable on the driver, but that's not the ideal way to do it. The output isn't adjustable on the fly though, it only has TTL modulation, not analogue.

RB astro · Nov 4, 2016

diachi said:
No problem!

Set up that way a potentiometer is actually a voltage divider, just a variable one.

Yes exactly, I realise that now, thank you, you saved me a bit of work.
:beer:

Dog said:
Do you know if that 400mw white eBay laser have individual modules that I can adjust the output for?

diachi said:
It'll have individual modules inside, yes. It looks like they are adjustable on the driver, but that's not the ideal way to do it. The output isn't adjustable on the fly though, it only has TTL modulation, not analogue.

Dog, diachi is spot on.
That unit has three individual input channels for RGB control but they are only TTL (or 'digital') not variable analogue like my unit is.

This means the channel is either full on at 5v or it's at zero volts.
You either turn each channel on or off.
Sorry I'm trying to explain it simply.
The info on the ebay ad says:

Modulation: TTL 0-30kHz /0V off and 5V on

This means you can drive each channel on and off up to 30kHz or 30,000 times a second.
The three RGB channels at 5v TTL are shown on the photo below, on the far right hand side of the board.

Hope that all makes sense.

RB

diachi · Nov 4, 2016

RB astro said:
Yes exactly, I realise that now, thank you, you saved me a bit of work.
:beer:

Dog, diachi is spot on.
That unit has three individual input channels for RGB control but they are only TTL (or 'digital') not variable analogue like my unit is.

This means the channel is either full on at 5v or it's at zero volts.
You either turn each channel on or off.
Sorry I'm trying to explain it simply.
The info on the ebay ad says:

Modulation: TTL 0-30kHz /0V off and 5V on

This means you can drive each channel on and off up to 30kHz or 30,000 times a second.
The three RGB channels at 5v TTL are shown on the photo below, on the far right hand side of the board.

Hope that all makes sense.

RB

No problem!

One thing you can do with TTL if you just want to adjust brightness is use PWM, that's fairly straight forward (although less so than a simple potentiometer). However, that doesn't adjust the actual output power, only the average and thus the perceived brightness.

RB astro · Nov 4, 2016

diachi said:
No problem!

One thing you can do with TTL if you just want to adjust brightness is use PWM, that's fairly straight forward (although less so than a simple potentiometer). However, that doesn't adjust the actual output power, only the average and thus the perceived brightness.

Yes exactly, PWM is the way to do it and as you say it's all done via the duty cycle of the TTL signal.
If the OP wants to do it that way then maybe an Arduino board can be a 'simpler' way, if he knows Arduino.

I was looking at that and was contemplating getting an Arduino controller, but I think for this one I'll keep it simple and just go with the sliders.
Now to work out some sort of host to make it all hand held.

:crackup:

diachi · Nov 4, 2016

RB astro said:
Yes exactly, PWM is the way to do it and as you say it's all done via the duty cycle of the TTL signal.
If the OP wants to do it that way then maybe an Arduino board can be a 'simpler' way, if he knows Arduino.

I was looking at that and was contemplating getting an Arduino controller, but I think for this one I'll keep it simple and just go with the sliders.
Now to work out some sort of host to make it all hand held.

:crackup:

Simpler still, you can do PWM with a 555 timer and some other components. Not going to comment on how to do it as I've never worked with 555s, I just know it can be done. That may be even simpler than an Arduino.

That's going to be an interesting host RB...

RB astro · Nov 4, 2016

diachi said:
Simpler still, you can do PWM with a 555 timer and some other components. Not going to comment on how to do it as I've never worked with 555s, I just know it can be done. That may be even simpler than an Arduino.

Yes, I used to do some basic circuits with the 555 about 30y ago, back then (and still are) very versatile and handy little packages.
That's the way to go but I would have to dig up some info on those too.
I've 'forgotten' a lot since I've been out of the loop for so long.

diachi said:
That's going to be an interesting host RB...

Yeah, 'Dr Frankenstein' comes to mind.... :crackup:

Dog · Nov 6, 2016

Ok, thanks for all the info. I understand what the problem was. So do any of you know where I could get a prebuilt RGB system with analogue modulation for each module? Would it be cheaper to get the individual modules with analogue drivers? If so, where would I get them? Again, <$80 if possible. I don't care what the output is, I just want the cheapest option for an RGB laser machine and it seems that eBay is not the best place to go to for this.

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