Magenta pointer?

[rocketparrotlet]

Would it be possible to build a magenta laser pointer? I know that it would require two drivers and two diodes, but would it be possible, using dichroics, to build a collimated magenta pointer with a single focal length? If so, how would you go about doing this?

(Note: I don't intend on actually building one. I just want to know how you could build one using optics.)

-Mark

 

[erdabyz]

It has been done with KES400 diodes from first ps3 sleds. But powering both the red and BR at the same time can kill the diode.

 

[danq]

It has been done with KES400 diodes from first ps3 sleds. But powering both the red and BR at the same time can kill the diode.

You might be able to get away with both at once, by using a pulsed circuit that alternates between the two.

Basically just a simple square-wave generating oscillator that switches two current regulators; one side gets an inverter (1 transistor would do it) between the oscillator and the regulator (crude block diagram below)

The focal length will be very different for the 2 colors though!

DanQ

 

[erdabyz]

[quote author=erdabyz link=1226119609/0#1 date=1226143479]It has been done with KES400 diodes from first ps3 sleds. But powering both the red and BR at the same time can kill the diode.

You might be able to get away with both at once, by using a pulsed circuit that alternates between the two.

Basically just a simple square-wave generating oscillator that switches two current regulators; one side gets an inverter (1 transistor would do it) between the oscillator and the regulator (crude block diagram below)

The focal length will be very different for the 2 colors though!

DanQ[/quote]

Yeah, easily done with a microcontroller and a pair of SMT logic level mosfets (and a voltage regulator for the micro if using more than 6 volts for the drivers)

 

[FireMyLaser]

It has been done with KES400 diodes from first ps3 sleds. But powering both the red and BR at the same time can kill the diode.

It is very possible with a good heatsink. I and Zom-B have done it, but Danq's idea is much better.

Can I use a 555-timer and adjust the duty cycle with just one pot to change the colour?

Would it be possible to build a magenta laser pointer?  I know that it would require two drivers and two diodes, but would it be possible, using dichroics, to build a collimated magenta pointer with a single focal length?  If so, how would you go about doing this?

(Note: I don't intend on actually building one.  I just want to know how you could build one using optics.)

-Mark

You can use the turning mirror from a DVD sled as a dichro to combine red with violet pretty good.

Edit: pic

 

[erdabyz]

[quote author=erdabyz link=1226119609/0#1 date=1226143479]It has been done with KES400 diodes from first ps3 sleds. But powering both the red and BR at the same time can kill the diode.

It is very possible with a good heatsink. I and Zom-B have done it, but Danq's idea is much better.

Can I use a 555-timer and adjust the duty cycle with just one pot to change the colour?

[quote author=rocketparrotlet link=1226119609/0#0 date=1226119609]Would it be possible to build a magenta laser pointer?  I know that it would require two drivers and two diodes, but would it be possible, using dichroics, to build a collimated magenta pointer with a single focal length?  If so, how would you go about doing this?

A 555 would require extra components and will make a big driver. Using a microcontroller like a PIC 12F629 (ultraexpensive) need only the microcontroller. No more. Well, it needs to be programmed, but that would be an easy program.

 

[danq]

Actually, if you make it an op-amp based regulator, you could use a quad op-amp (1 chip) for the 2 drivers; then a single 8-lead timer could be the divider... put all that in tssop packages and it's pretty small, even after adding the 2 power MOSFETS.

Below is a circuit, modified slightly from one by Phenol (hey, where's Phenol lately?)

 

[erdabyz]

too many resistors there, even if it includes the driver


I fuken love microcontrollers...

 

[FireMyLaser]

Well I don't understand a damn thing. ;D

 

[danq]

too many resistors there, even if it includes the driver  
I fuken love microcontrollers...

: we could do without that expression...
nevertheless, I've been trying to get into microcontrollers lately myself - what specifically would you use, to get the same functionality - perhaps adding in the pulse circuitry too ??


DanQ