Laser Projector (Red, Green, Purple) "Laser 3D Party Light" from Spencer's

[mixedgas]

Dog, the basic way to check damping is to hook a scope to the feedback signal and input a 30 Hz square wave to the galvo. Count the number of cycles/magnitude of ringing at the leading edge. Adding more servo gain should push the first cycle of ringing up a bit, unless its already critically damped.

The NO-POPS on the board at the feedback circuit might give a clue to some of the noise pickup. Looks like they chopped out parts on the current source for the leds.

Nice Job!

Steve

[DogP]

Nice work, DogP! I wonder why I didn't see any changes when I messed with the LIN pot.

I'm not sure I fully understand what it does, but it looks like some sort of balance between the two sensors, in which case it might just cause it to shift direction slightly. This probably wouldn't be too noticable, unless you marked exactly where it was projected on the wall, and didn't move the projector at all while adjusting. Or I could be completely wrong.

Anyone know where I can get a a set of probes compatible with Tektronix 2245? The ones I have are TEK P6121, but I'd like something I could clip test leads to because I don't have four hands.

Pretty much any scope probes will work... you have a 100MHz scope though, so if you get too crappy of probes, you'll lose performance if you try to look at a 100MHz signal. These claim to be 100MHz probes: http://www.ebay.com/itm/New-100MHZ-B...item3f1265fb93 ... at $7, I can't trust that they actually are (or their definition of good at 100MHz may be a little lax), but I'll bet they'd work fine for most stuff you want to do. My digital scope came with some cheap Chinese probes, and they actually work pretty well (there's some noise if you rotate the cable at the BNC connector, but oh well). And they come with the clips, which you can probably use with your good (broken) probe if you fix it. I also use BNC to alligator clips and BNC to grabbers, but those don't work well for high frequency.

Dog, the basic way to check damping is to hook a scope to the feedback signal and input a 30 Hz square wave to the galvo. Count the number of cycles/magnitude of ringing at the leading edge. Adding more servo gain should push the first cycle of ringing up a bit, unless its already critically damped.

Ah... cool.

The NO-POPS on the board at the feedback circuit might give a clue to some of the noise pickup. Looks like they chopped out parts on the current source for the leds.

The NOPOPs are the 22pF caps above U4A and U4C on the Cambridge schematic (across the 100k at U1C, U1D, U4D, and U4C on my drawing)... they put the pads there, but I guess they decided that 4 22pF caps would add too much to the cost. I have some 22pF caps here, maybe I'll populate them. I don't feel like computing the low pass filter frequency w/ a 22pF right now, but maybe it'd be an improvement.

Oh, and yes... I mis-drew the two 2k resistors on the schematic. The left resistor (going to +) should be connected to the amp coming from Photo 2, and not connected to the output of Photo 1. I'll fix this later, and label the sections, to make it easier to read like the Cambridge schematic layout.

DogP

[ben174]

Any clue where I could find a nice collection of these ILDA files to pump onto the SD card that comes with this projector? I'm super excited to have this card full of random animations

[mixedgas]

Put in .01 uf or something if they fit. 22 is nothing.
The linearity control really matters in industrial work and printing. One thing it does do is reduce the amount of offset work the final amp does, which is good.

Steve

[james]

http://laserboy.org/forum/index.php?...sg6369#msg6369

DogP and tribble, could you please share the optimization settings you use in LaserBoy?

James.

[DogP]

Any clue where I could find a nice collection of these ILDA files to pump onto the SD card that comes with this projector? I'm super excited to have this card full of random animations

I just searched on Google for ilda files, and checked out various ones that looked interesting. You should also check out: http://www.photonlexicon.com/forums/...-November-2011 . But, as discussed many times in this thread... this projector only plays format 0 files, so don't expect to just download and play any file you'd like.

Put in .01 uf or something if they fit. 22 is nothing.

Yeah, I popped a 22pF cap in last night, and as expected, it didn't do anything noticable. Why do you suggest a 0.01uF? I imagine the guys that originally made the circuit knew what they were doing, and this is (mostly) a copy of that.

http://laserboy.org/forum/index.php?...sg6369#msg6369

DogP and tribble, could you please share the optimization settings you use in LaserBoy?

Cool... I'll give that a try when I get a chance, and post my settings.

DogP

[james]

Here's some stuff, but you will need to load it into LaserBoy, optimize it and apply the "spencer" effect in the version of LaserBoy listed above.

http://laserboy.org/free_art/

James.

[tribble]

http://laserboy.org/forum/index.php?...sg6369#msg6369

DogP and tribble, could you please share the optimization settings you use in LaserBoy?

James.

Cool, definitely looking forward to trying that! Right now it's looking like Friday or Saturday is the earliest I will have a block of laser time. I will try to have some feedback for you by Sunday.

I will post my LB settings when I next get it running on my other workstation... I don't recall all the settings off the top of my head, but I think the max lit/blank lengths are around 4000 and I set the output rate to 15000 in case it affected dwell timings. That could probably be higher per DogPs 'drawing burst rate' timing measurements. I'm pretty sure I diddled with some settings that didn't need to change, too, like lit dwell overhang, but I don't remember the defaults.

[james]

Well, tribble, you're the one who came up with the steps you thought would fix the problem. I just tried to put those ideas into my code. You should go over it carefully and see if it is in fact what you wanted!

Remember, I have no way to test it!

James.

[prosound73]

Well, I just purchased one of these from my local Spencer's at the mall, they only had one in a box. The display unit looked very impressive on their "screen" they had on display. The green was was over powering the other colors but gave that nice argon look. I did have to pay $169 US plus tax, unlike others that have found this product locally for sale at $129. I let the unit reach room temperature at 72 degrees even before taking it out of the box. Once plugged in, the green was non-exsistant. After a few minutes, i did see a faint green, but it never reached full brightness. The next thing I noticed was all 3 colors were really mis-alligned. The lack of green was not due to alignment problems, I could see a very faint pulse of green from the diode module. Other local Spencer stores have as many as 18 in stock, and will be exchanging this one soon, after I pull it apart and see what I'm dealing with. I don't even know if this is a 1st or 2nd generation of this product yet until I get inside the unit. I'll test all 18 in store if I have to, and grab the best one. I did ask about the store's display model, and they said it's been running every day since October, and that unit still looked really good. I have big plans in this new expensive, highly addictive hobby of mine....I already bought a FB3 with QuickShow last week, I don't even own a projector yet, and I want Beyond.