Topic: My New Projector

[Lazerjock]

Now that the white light laser pointer is done, I am moving on the the next project. I'm building a new projector. I have all of the components. I just need to put them all togother.
It will consist of:

-Sound Card DAC
-Turbo Track AMP
-Cambrige 6800 scanners
-150 mw of 532nm Green (TTL Modulation)
-130 mw of 650nm Red (Analog Modulation)
-75 mw of 405nm BluRay (Analog Modulation)
-Lumia wheel
-Machita diffraction grating
Any other toys I can cram in there.

I can't wait to start playing with all of the software available.
Pictures of the build progress soon.

[BlinkenLights]

what do you have already?

i have a 150mt TTL green that needs a new c-mount diode for sale.. 80 bucks.

[Lazerjock]

That is a list of what I have already. I don't need anything.

[James]

Don't need anything?

How about some time and motivation?

Or perhaps some encouragement?

Go Lazerjock!

James. 

[Lazerjock]

Well I am waiting for my friend to fix my Turbo Track Amp. I have started to clean up the case it's all going in.

[Lazerjock]

On Dr. Lavas recomendation I decided to double up my red output. I ordered a PBS to combine two red diodes into one beam. I already have a spare mount, diode and driver.
If it works well I may double up the BlueRay too.
I may start laying out the table tonight. Lots of drilling invloved. We'll see how much drive I have once I get home.

[BlinkenLights]

i live my dual red.. i use a single driver..

[drlava]

Last time we met, that machita grating really impressed me.  How do you plan to incorporate that into your projector?

[Lazerjock]

i live my dual red.. i use a single driver..

BlinkenLights / Dr.Lava

How do you set the driver current? Is it any different than normal? Are the diodes in series or parallel?
If it works I'll do it that way too.

I figured each diode needed its own driver.

[Lazerjock]

Last time we met, that machita grating really impressed me.  How do you plan to incorporate that into your projector?

Yea, I plan to put in the Machita grating and a Lumia wheel too. I have lots of room, I will cram anything I can in there.

The main question is how do I control the pick off mirrors.

I am an old Pangolin user, it had TTL outputs that could be programed right into the show. That allowed me to trigger any effect I needed any time through out the show. That is how I controlled my master shutter, Lumia, and all my beam shots.

I know Hyena is working on it. Maybe James can work it into Laserboy too.

I will incorperate the effects into the projector with the potential of TTL control. Worst case, I can go old school and conrtol it through push buttons. (AKA live)

I know there is also DMX, but I think I want to stay away from that.

[drlava]

the EzAudDac can have TTL, just need to program it...

For multi-diodes on one driver:

yes you can run many diodes of the same type from one driver, just stay within the current limitations of the driver (6A max)

Each diode is slightly different, so to even out the current draw between the diodes when they are in parallel, you should put a (thick) metal film resistor in series with each diode. This is true for driving parallel diodes no matter which driver you use.

Let's say you are making a super red and want to use as many red diodes as possible, and you want the max current to be 300mA to each diode, and the lasing threshold is 75mA. Choose a resistor so that it drops about 10% of the diode voltage at the idle current, or 0.3V at 75mA: 4 ohms. Then calculate its voltage drop and power disipation at full power: 4 ohms*300mA = 1.2V; 1.2V*300mA= 0.36W

So, for an array of open can diodes you should use 4 ohm, 1/2W or 1W resistors in series with each diode. Maximum number of diodes on one driver is 6A/300mA = 20 diodes.

Minimum power supply voltage for the driver would be 3V (diode voltage) + 1.2V (resistor voltage) + 1.5V (Driver requirement when delivering 6A (0.25V per amp)) = 5.7V. If you are only driving 2 diodes in parallel then a supply voltage of 5V is fine.

Finally, your diodes should be of the same make and model, and thermally coupled so they stay close to the same temperature, and electrically isolated. They should be connected to the same size heatsink block and with the same length and type of wire.

Typically if a red diode dies, it dies of optical failure and so will maintain virtually the same output voltage drop, saving the other diode it he pair. However if it fails open circuit via some mechanical abuse (I have never seen this happen after a diode was installed in a mount, but have seen it happen AS a diode was being installed, so test!) then the other diode will take double the current.

[BlinkenLights]

i have popped a few diodes and i can tell you that the second diode is always OK, as Andrew said.

The dual red on a single driver seems to be the way to go. not just for cost, but it makes everything that much simpler and smaller.

[Lazerjock]

Thanks Guys

[James]

There are 12 outbound bits on a parallel port!

I know people complain about the fact that the parport has low priority in most kernel models and that streaming data might get a glitch or two in it....

But think about it. All you need is a set of lines that you can switch from lo->hi or hi->lo in a "reasonable" time. That's not quite the same as a continuous stream of data.

Parport programming is easy! That thing is a lot faster than you might think! All you need to do is bang a number to an address in RAM.

James. 

[BlinkenLights]

the parallel port is deprecated. new pc's don't even have them.