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Building a "everycolor" / RGB >3W Laserpointer

farbe2

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Update:

Sorry to disappoint, but no pictures this time.

I did manage to print the plugs for the interlock "key" and the programming header. This works great and looks nice.
I also printed the updated case with the battery door. Everything fits perfectly. It did pay off do design everything in CAD beforehand.
I dont have aluminium tubing at hand, so i ordered some. I hope it will arrive soon. In the meantime i will mill the foot and make a wooden storage box. Still no idea how to improve the user interface.
However i am very pleased with the result so far!

What buck IC are you using?
... pwm frequency?...
I use 10khz PWM frequency and a standard LED constant current LED driver IC. But i will not tell you the exact IC, because i am hoping to sell some of the finished drivers.
I did use a filter with around 2ms settling time, giving me theoretically about 8% current ripple. I didn't see any visual artifacts while moving the beam around and the current trough the LD is completely spike free and relatively smooth (do to a second pole inside the driver IC), so i kept the low settling time. This enables me to "scann" to an extend. Just like a Laserprojector would.
I do have a special color fade mode. If this mode is enabled, and the pointer/beam is moved fast enough, it draws a dotted line / rainbow lines and so on. I also use a lookup table to get gamma correction and threshold current for the laser diodes.
 



farbe2

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Just another teaser for today.
This is the color Jump and color fade mode.
Is this the only pointer that can draw rainbow lines when it gets moved but having a white beam while not moving?
color jump mode.jpg
rainbow_slow2.jpg
rainbow_fast2.jpg
 

ArcticDude

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Is this the only pointer that can draw rainbow lines when it gets moved but having a white beam while not moving?
Nope, that's pretty common output for low freq PWM / IC's. > Changing processor to higher PWM Frequency and Resolution 16-bit or higher, eye can't see the "dashes"

Just an example >
 

farbe2

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I think you got that wrong ;)
I programed a fast but not to fast rainbow fade to get a pointer that can draw rainbow lines. ;)
Just look at the rainbow fade, the PWM frequency is not noticeable (no dashes). Otherwise the PWM would beclearly visible.

Nevertheless: does sanwus RGB pointer (or any other) offer a rainbow mode thats fast enough to draw rainbow circles?

BTW: I just need the magnets (battery cover) and a fabric "tape" as a battery removing helper. Otherwise its finished.
 

ArcticDude

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No I did not get that wrong. For your eye it seems there is a "fade", try to shoot with HI speed camera and you will see. With PWM there will be always "Dashes" in some sort. If you want seamless / fluent RGB you will need analog modulation.

EDIT:
Sanwu uses +100kHz modulation which has transformed to analog signal. > PWM signals can be transformed into analog signals using a simple RC type low-pass filter.

EDIT 2:
What frequency you IC is running?

 
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farbe2

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No I did not get that wrong. For your eye it seems there is a "fade", try to shoot with HI speed camera and you will see. With PWM there will be always "Dashes" in some sort. If you want seamless / fluent RGB you will need analog modulation.
Thats exactly what's done here.
I have a rc filter with around 2ms settling time and 10khz pwm thats driving it. The step down constant current driver "converts" that signal into a steady current that gets supplied to the diodes.

Just look at the post #33.

So actually the diodes are truly on the whole time.

But the fast settling time of the "pwm-dac" allows me to turn the diodes on/off/change brightness very rapidly. Allowing me to change the brightness while the beam is moving. This will give the illusion of rainbow colored circles in this example.


The steady current trough the laser diodes gives another advantage:
If the pointer is commanded to only give 20% power, the diodes will be running at 100% duty @ 500mA (for example) vs 20% duty @ 2,1A.
This will reduce the overall resistive losses (I² * R !!) thus increasing the batterylife and reducing heat, while increasing diode lifetime.
 

ArcticDude

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Also, is your IC able to run channel modulation separately / independently?

EDIT:
Is this the only pointer that can draw rainbow lines when it gets moved but having a white beam while not moving?
Reason why your RGB draws rainbow in white mode is because channels / timers are runned in row, not simultaneously.
-If you have IC that runs channel / timers simultaneously you can't get any "rainbow" in white mode. -Only white
 
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farbe2

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Yes, i do have 3 completely separate stepdown converters on there. The post #12 and #1 shows pictures and layout of the pcb. You can see that there are 3 inductors along with 3 buck driver and the uC.
EDIT:
Sanwu uses +100kHz modulation which has transformed to analog signal. > PWM signals can be transformed into analog signals using a simple RC type low-pass filter.

EDIT 2:
What frequency you IC is running?


I did not see that sanwu has the PWM frequency mentioned anywhere on his site. Where did you get that +100khz from?
However i dont understand why the pwm frequency matters so much to you?
I dont think it matters, if its high enough to get a filter that has a low settling time and still offers good enough smoothing it should be allright?

Does the sanwu pointer offer a rapid color cycle mode? I did only see slow modes on some random youtube videos. I did think this mode is super nice to have. Should be doable with +100khz pwm frequency.

What do you mean with "what frequency you IC is running?"
Do you mean the buck converter? That also does not really matter to the finished product. Lower frequency's would give you higher efficiency's while needing a bigger output filter to get low output ripple. Higher frequency's on the other hand, would give you smaller inductors thus reducing size while increasing switching losses. I did choose the later to the the size as small as possible.
 

farbe2

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...white doesn't draw any rainbow regardless how fast you are moving the laser. It's all white...
Seams like we still talk a different language. No offense here, just trying to make it clear.

My pointer does have a "color choose" mode. In this mode, the brightness of each laser (R / G / B) can be adjusted independently.
Something like 50% Green 60% Red 100% Blue for a really cold white is possible (any combination actually). This mode just displays the fixed color, the uC does PWM, it gets filtered, the buck driver drives the laser diodes at constant current. ("analog")
Moving the pointer in this mode will give you solid lines, no dots, no dashes, no rainbow, no fades. Just solid on with the chosen color.

However i also have a "Rainbow" mode, it will display a "white" beam with around 30% power, because each laser is quickly dimmed up and down so only one diode is fully on at a time.
The beam is not really white, it only appears white because our eyes are slow and cannot perceive the fast color change. Moving the pointer with this mode on will give rainbow colored lines, or "hard" changing color dashes if in "color jump" mode.
This mode is controllable, adjusting the speed will give you a long color cycle (2. picture) or a faster like the 3. picture.
setting the speed slower that picture 2 will give you a slow changing rainbow beam.

So i can do both, solid white (even while dimmed down) and colored lines.
 

ArcticDude

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Yeah I have build programable RGB's which gives rainbow lines in different variety in "white mode" while moving the beam -depending dimming speed and selected mode, so my answer to your question was Nope.
Is this the only pointer that can draw rainbow lines when it gets moved but having a white beam while not moving?
 
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farbe2

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I see, however, your post did imply that its caused by a slow IC / that i do use a slow IC or / and that i should change my PWM frequency and / or uC to make it "better".

However i would like to state that i do this on purpose to get the effect because i like it and i couldn't finde a pointer that does the same.

... I have build programable RGB's...

Do you have a build log? Would be nice to get some inspiration for future projects.
 

ArcticDude

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to get the effect because i like it and i couldn't finde a pointer that does the same.

Many RGB pointer projects have be done here in LPF many years ago, here's few of 'em

EDIT:
I see, however, your post did imply that its caused by a slow IC / that i do use a slow IC or / and that i should change my PWM frequency and / or uC to make it "better".
Ok, I just understood you wrong, I thought you asked if that's normal if white beam draws rainbow lines while moving the laser.. That's pretty common with low freq. PWM's
 
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farbe2

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Nice recommendation but the first one has sadly no pictures. But seems very interesting!
Second one is also nice, seems like it did never get done :(

But these two are not from you? You said you also build some? Any info available there?
Would be nice to see your user interface and RGB modes.
 

ArcticDude

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Nice recommendation but the first one has sadly no pictures. But seems very interesting!
Second one is also nice, seems like it did never get done :(

But these two are not from you? You said you also build some? Any info available there?
Would be nice to see your user interface and RGB modes.
Yeah, old pictures from those threads are lost due Photobucket but I have saved all the media of those threads somewhere.. I'll need to locate & ZIP them..

Don't wanna trash your thread..
Here's some sort of preview of RGB ui / modes

Will PM you more info's + media of my builds, UI & RGB modes are coded with assembly and they are pretty much open source stuff. (theres huge amount different programs/ RGB modes.). Need to find infos. -Also some of build logs are on "Vet" section which you don't have access, so I'll try to make some sort of wrap-up.

Also some info can be found from Sanwu RGB thread
 




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