Tiny projector build

Along with the j4cDAC, I've been working on my first projector build, and it's now getting pretty close to done...

http://farm6.static.flickr.com/5299/...cb8031af_z.jpg

More photos of the case here.

It's tiny - 6" by 8" by a bit over 3". Inside is a "200mW" green pointer core from eBay, two LOCs, a blue diode, a set of PT-30k galvos, and a j4cDAC.

Here's what it looked like before I built a case around it:

http://kremvax.su/j4cbo/projector-on-tripod-1.jpg

http://kremvax.su/j4cbo/projector-on-tripod-2.jpg

The driver board is three simple opamp-and-BJT high side CCSes, plus a TI buck converter module to provide a 6.5v rail for the diodes from the main 24v power supply. I built it from scratch on some perfboard.

http://kremvax.su/j4cbo/projector-on-tripod-3.jpg

There is no mains inside the projector. A small laptop-type power supply provide the main +24v supply, which powers the diode driver board, DAC, and galvo drivers. Additionally, a DC-DC converter provides the -24v galvo supply. This lets me keep most of the PSU bulk encapsulated and saves a lot of space. I'd really like a galvo driver board that drives the galvo coil push-pull with an H-bridge arrangement from one rail, but oh well.

http://kremvax.su/j4cbo/projector-on-tripod-4.jpg

There's a cutout in the bottom of the baseplate to facilitate messing with the mirror adjustment screws. It's covered with a piece of plastic in the assembled projector.

http://kremvax.su/j4cbo/laser-closeup.jpg

Here's a closeup of the diode module. The LOC diodes are in dave's mounts, modified for isolation (I posted a thread about it). Green is in a cut-out clamp, and blue is in an unmodified dave mount. The PBS was provided by swamidog, and comes from a LaserDisc player. (Swami, I still owe you some mirror mounts. Thanks!)

Most of the construction photos are a bit old. I've flattened out the lasorb assemblies and diode wiring, so the highest point off the baseplate is now the edge of the galvo drivers and the connectors on the j4cDAC.

The thread would not be complete without photos of light coming out of it. Here are some beam shots in fog -
http://kremvax.su/j4cbo/pew1.jpg
http://kremvax.su/j4cbo/pew4.jpg
http://kremvax.su/j4cbo/pew3.jpg

And, last night we got some video of it running dchammonds' abstract generator:

http://www.youtube.com/watch?v=3sMZIQU8SiQ

Now I'm debating spending some cash on a 637nm diode...

http://www.photonlexicon.com/forums/...6&d=1262150220
...............

I like your set up:D.

Very compact.
And mounted on a tripod awesome.*retardo

Cheers,
Ed

That is a cute clever build :)

Nice build!

I have also been planning something like this as my next build.

Where did you get the 24V to -24v dcdc?

I ended up building my own last time i needed one...

The vertical beam table is a great idea - saves a lot of space *retardo

/Thomas

Thanks!

The DC/DC converter is a Mean Well PSD-30B-24. Mouser carries them. It's rated at 1.25A output; the PSU that came with my galvos is rated at 1A per rail, so the new one is plenty. Different galvos may need more, though.

The trick is to use an isolated converter and wire up its positive output terminal to ground. Then its output negative side provides -24v. The layout is like so:

http://kremvax.su/j4cbo/projector-power.png

The laser driver module uses a TI PTN78020 to give me an intermediate rail suitable for the diode CCSes.

Quote:

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Originally Posted by j4cbo

Thanks!

The DC/DC converter is a Mean Well PSD-30B-24. Mouser carries them. It's rated at 1.25A output; the PSU that came with my galvos is rated at 1A per rail, so the new one is plenty. Different galvos may need more, though.

The trick is to use an isolated converter and wire up its positive output terminal to ground.

---

Clever solution - didn't think of using an isolated dcdc - only downside is their size... 100x50 mm is huge, put next to the 40x40mm nonisolated inverter i built.

On the other hand, M.W. supplies are dead cheap - ~16 euros won't even get you the pcb for a diy design *retardo

/Thomas

Yeah. What I'd really like is a full-bridge galvo driver that doesn't require a negative rail (instead driving both ends of the galvo coil), but I don't think any such thing exists...

TI has some negative-output POL modules, but they only go up to -15v.

Quote:

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Originally Posted by j4cbo

Yeah. What I'd really like is a full-bridge galvo driver that doesn't require a negative rail (instead driving both ends of the galvo coil), but I don't think any such thing exists...

---

True - something like a TDA7391 would do nicely as a galvo driver:
http://www.st.com/internet/automotive/product/65194.jsp

Quote:

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Originally Posted by j4cbo

TI has some negative-output POL modules, but they only go up to -15v.

---

I know - that is where I stranded last time I was searching, and ended up building my own around a LT1074HV... If only I had thought of the isolated dcdc idea back then :(

/Thomas

That's a really excellent build. Very clever optics arrangement. Did you use the same tape used in dave's mounts to isolate the your green?

Adrian

Yep, the green is wrapped in kapton tape too. In retrospect, I could have put it on a TEC without really taking up any extra space in the optics section - next time!

Very nice work, your mounts for the optics are very clever !

Can you educate me if the laser pointer setup is suitable for blanking. Looks like you are using the driver module that came with the pointer (see attached picture). In other words, is the driver board that comes with the pointer quick enough to turn the laser on/off for scanning or would the laser diode need to be driven directly ?
Attachment 24428 This might be a dumb question but it is not obvious from the reading I've done... Also not sure if you are doing blanking on this projector but I'm guessing you are due to the homebuilt perf board that looks like it could be an RGB driver for the LDs?

Your project really has provided motivation, thank you! :D

Jason

Originally, I left the driver that came with the green module attached, and drove it with the output of my driver. This worked surprisingly well. The built-in module is just a fixed CCS, so by running it from the output of another CCS it was basically being kept in a constant state of dropout. In this case, the limiting factor for modulation performance was the shitty DPSS itself, not the drive of the pump diode, but it's still better to remove it. I replaced it with a modified LaserBug. The pinout on IR diodes is like that for LOC reds, but the other way around, so I desoldered the LASORB from the LaserBug and flipped it around. You can see how it is now in the second and third photos.

The perfboard is three analog-modulated CCSes and a buck converter, yes.

really nice build... I am always jealous of the microprojector builds so portable!

you could save space by making an external PSU... just put a multi-pin connector like an XLR or something

OR you could find a 48v power brick and then use a rail splitter inside the projector (going to be a lot smaller than a DC-DC converter)

Sweet.
Yeah, I too was looking at those pointer type greenie oem modules. Thinking of putting 4 of 'em (knife-edging+pbs /something) @ 150mW ea to make 600mW of green to match the great higher 445 blue power that is now available to us (in a compact size).
Nice build ya got there.Attachment 24476

ps- another point made on this thread is the external PS that I'm going with. No switcher 4 me, just a big 12V tranformer (10A) , bridge rect and caps in a portable separate box with a handle (Sturdy.) The regulator chips (LM338/etc) may be in the projector cabinet, haven't decided that far in advance yet :D

very nice work!
I should learn more about the laser projector!

Hi Jolie.
Do you have a 532nm oem unit like this designed for continuous use (non-off-on duty cycle)?
400mW solid green laser module/adjustable/IR filtered

http://www.o-like.com/images/high%20green%201.jpg

Quote:

---

Originally Posted by steve-o

Hi Jolie.
Do you have a 532nm oem unit like this designed for continuous use (non-off-on duty cycle)?
400mW solid green laser module/adjustable/IR filtered

http://www.o-like.com/images/high%20green%201.jpg

---

Dear Steve,

Please look at the follow picture of our module. The optics in the small box is the infrared filter and collimatior lens.

Attachment 24499

Quote:

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Originally Posted by Jolie

Dear Steve,

Please look at the follow picture of our module. The optics in the small box is the infrared filter and collimatior lens.

Attachment 24499

---

Hi Jolie,

I can't see this module on your website. Can you provide the specifications please?

Is it analogue modulation
What is the power
What are the dimensions
What are the power requirements
What are the pricing options


Thanks,
Tony

Thank you for the response, Jolie.

That is a very attractive module.
Can you provide us with some additional information please?
Such as:
Beam specifications: diameter and divergence,
Power output,
Pricing,
Operating temperature,
Transverse mode characteristics,
Voltage and current requirements,
and warranty information.

Thank you very much,

Steve

Quote:

---

Originally Posted by taggalucci

Hi Jolie,

I can't see this module on your website. Can you provide the specifications please?

Is it analogue modulation
What is the power
What are the dimensions
What are the power requirements
What are the pricing options


Thanks,
Tony

---

hi tony,

it is the part of the green heldlaser.You could see the specification on http://www.lasever.com/producttitle.asp?id=1383
We could supply it at 150~600mW. And it feed with battery. About the price, could you please confirm which power you are interested in?

Quote:

---

Originally Posted by steve-o

Thank you for the response, Jolie.

That is a very attractive module.
Can you provide us with some additional information please?
Such as:
Beam specifications: diameter and divergence,
Power output,
Pricing,
Operating temperature,
Transverse mode characteristics,
Voltage and current requirements,
and warranty information.

Thank you very much,

Steve

---

Dear Steve,

This is part of the green heldheld laser. Please find the specification as follow:

1) Spatial Mode: TEM00
2) OutPut Power: 200~600mW
3) Residal IR(1064 & 808nm) :<0.01%
4) Operation Mode: CW
5) Pointing stability: < 0.05 mrad
6) Beam shape: round
7) Beam Diameter(1/e2):2mm
8) Beam Divergence:0.8 mrad
9) Battery Voltage: 3.7V
10)Operating Temperature:15~30oC
11) Dimensions:Φ26x54
12) Warranty: 6 months

The price is different for different power. If you need one piece at 400mW, the price if USD390/PCS+ freight charge.

If you need more information, we could contact by email:)

What is the current draw of the 400mW module?

Quote:

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Originally Posted by j4cbo

What is the current draw of the 400mW module?

---

Hi,
the current draw of the 400mW module is 2A

how about an evaluation samples so we can test modulation characteristics determine if its suitable for projector use?

Quote:

---

Originally Posted by Jolie

Hi,
the current draw of the 400mW module is 2A

---

Quote:

---

Originally Posted by swamidog

how about an evaluation samples so we can test modulation characteristics determine if its suitable for projector use?

---

In fact, most of our customer use our laser module for their projector. You can see the detailed specification on http://www.lasever.com/product.asp?id=575

That page seems to be for lab-style modules with built-in cooling and a dedicated driver circuit. Presumably, your small module uses a different design; I'd be interested in investigating its performance.

Jolie,

Thank you for your responses. This is good information. There is a lot of interest in a small 532nM module that we can supply our own power to and build our own heatsinks/ TEC. This is very space-saving and friendly to laser projectors that we build. :) Thanks.

Regards,

Steve

Quote:

---

Originally Posted by steve-o

Jolie,

Thank you for your responses. This is good information. There is a lot of interest in a small 532nM module that we can supply our own power to and build our own heatsinks/ TEC. This is very space-saving and friendly to laser projectors that we build. :) Thanks.

Regards,

Steve

---

Steve,

Very glad it is uesful for you!

If need more information about our products, please feel free to contact me :)

Thanks!

Jolie

Quote:

---

Originally Posted by Jolie

Steve,

Very glad it is uesful for you!

If need more information about our products, please feel free to contact me :)

Thanks!

Jolie

---

Hi Jolie,

One of the most important factors for us is analogue modulation so we can create lots of different colour shades when mixing with red and blue.

How can we modulate these 12mm diameter modules, for example a 200mW unit at 10kHz? The driver board pictured seems suitable for battery only, not for laser show with analogue modulation. I can only see power wires, no modulation wires.

Thanks for your help.

Cheers,
Tony

Absolutely beautiful work. VERY nice job on layout and integration.
*retardo*retardo*retardo*retardo

Quote:

---

Originally Posted by taggalucci

Hi Jolie,

One of the most important factors for us is analogue modulation so we can create lots of different colour shades when mixing with red and blue.

How can we modulate these 12mm diameter modules, for example a 200mW unit at 10kHz? The driver board pictured seems suitable for battery only, not for laser show with analogue modulation. I can only see power wires, no modulation wires.

Thanks for your help.

Cheers,
Tony

---

Hi Tony,

Yes, the module as the last picture suitbable for battery. But we can provide the modules with analogue modulation. The operation mode for our green laser as follow is analogue modulation.Attachment 24561http://www.lasever.com/producttitle.asp?id=1397

Quote:

---

Originally Posted by Jolie

Hi Tony,

Yes, the module as the last picture suitbable for battery. But we can provide the modules with analogue modulation. The operation mode for our green laser as follow is analogue modulation.Attachment 24561http://www.lasever.com/producttitle.asp?id=1397

---

Thanks Jolie, but...

I think many of us want to use the battery-sized 12mm diameter module with analogue modulation, not the typical modules you show in that picture. These are not compact enough. Can you explain what options we have for modulating these smaller 12mm modules?

Quote:

---

Originally Posted by taggalucci

Thanks Jolie, but...

I think many of us want to use the battery-sized 12mm diameter module with analogue modulation, not the typical modules you show in that picture. These are not compact enough. Can you explain what options we have for modulating these smaller 12mm modules?

---

I expect she is pointing you to the OEM lab modules because they have TEC's for stability and will hopefully modulate better than a standalone OEM green 'pointer' style core. As J4 did with his module, replacing the driver with a different one would probably be cheapest option.

I am sure that they could use the driver from one of the lab style green, but then the TEC outputs would be unused. If that was the case it would give you the option of using those ouputs later if documentation was provided. *retardo I expect that voiding your warranty and soldering on a flexmod, die-for-drive, or soon to be stevemod driver is the analog modulation method.

.02,
Adam

You could try one of these:

http://cgi.ebay.com/200mW-532nm-DIY-...item336699315b

Seem to be inexpensive enough. I'm curious how they hold up against the CNI baby OEM.

Quote:

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Originally Posted by Stoney3K

You could try one of these:

http://cgi.ebay.com/200mW-532nm-DIY-...item336699315b

Seem to be inexpensive enough. I'm curious how they hold up against the CNI baby OEM.

---

I really doubt that that produces 200mW of green with 450mA into the pump diode. There also appears to be no IR filter.

Quote:

---

Originally Posted by j4cbo

I really doubt that that produces 200mW of green with 450mA into the pump diode. There also appears to be no IR filter.

---

I agree, I ran into this with a little green of my own.

Jolie:
I still have some questions. I think you could sell some of these here if we know more about them. The people in this thread don't mind machining and doing our own electronics work. We also are looking for small modules. We know about the bigger lab modules with separate power supplies but we are looking for compactness.

Here are the questions.

1. How much money for 200mw after IR filter, 400mw after IR filter. Without Driver board. We will supply our own driver.
2. Is the module isolated from Diode + and - or is it connected to one of them.
3. What is the ideal temperature of the module? What temperature do you test it at?
4. Do you have a graph / chart of the mw output versus temperature? (at a set current)
5. Do you have a graph / chart of current versus mw output? (at a set temp)
6. What are the exact dimensions? Diameter - Length.
7. What are the dimensions of the collimator / Ir filter end cap. Diameter, thickness, thread specifications, Ideal distance from DPSS module, hole size and distance for spanner wrench.
8. What are the specifications of the collimator lens? OD, focal length. Can we get the lens and IR filter unmounted. (maybe we can tweak the lensing a little to get them to match the reds and blues better)
9. What is the threshold current. (at a given temperature)

That is all I can think of right now.

Thank, You.

chad

Jolie:

I and others still would like some information on these modules. As a company making lasers none of these questions should be difficult to answer. I am just a laser hobbyist however I have the capability of preforming all of these tests I cannot believe that as a manufacturer of lasers you can not supply this information. Nothing I asked for is property or should be a secret.

Thanks,
chad

p.s. J4 sorry for the thread jack and your little laser looks great!

Laser-wave is selling similar modules with analog modulation driver included:

http://www.laser-wave.com/en/2009/0121/article_31.html

That may be the way to go if Jolie cannot give us any data?

Though I'm still liking j4's one-for-all driver... Saves a lot of space.

I'll need two of these small 150-200mW modules in the near future for a pair of satellite (micro) projectors... Maybe someone could arrange a group buy? >:)

/Thomas

Good find! If it came from Bridge and laser-wave I would be more inclined to believe the specs.

I still would like to see the modulation power graph.

chad

Bridge is a good guy. I bought a 473 from him a few years ago. I wonder if we can get prices for these modules from him? He's a member here on PL.