09-11-2012, 06:33 PM #1
Class 2 Laser
Join Date: Feb 2012
Location: UK
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Default RGB hand-held laser


I've been working on this project for a while, several months+ and it's time to start cutting some metal this week.

The laser head contains the 3 lasers, planned to be 400mw of red, 150mw of green and a M140 for blue which will be set about 500mw or so to give the best colour balance.
I may have to crop the beams to ensure a decent overlap of the RGB, but also have a idea that may help reduce the width of the red beam to get a good RGB overlap

I've also working prototype microprocessor that with control the laser brightness using PWM, so I'll easy get 32 decrete visible steps on each laser giving 32,000 "colours". - never see this many by eye, but its good bragging rights

The design 'twist' is that I'll have a LCD to display and control the modes.
As seen in the 3d model, the optics bay has 4 recesses for 2 dichroics and 2 mirrors. The cover plate that bolts over the bay will have the lcd recessed into it.
Small holes above the 3 laser module holes are for the lcd cabling to the u.p. board.

The small recess in front of this will have one of those micro 5 way joystick switches to slect the modes from the LCD menu.

the half moon shape is the driver tray / heat sink - I intend to fix the drivers to a small piece of ali and bolt this to the driver tray via 3 M2.5 screws. This will alow for easy servicing and removal of the lasers.

A threaded tapered cone will connect the laser head to the battery tube and enclose the drivers and u.p board.
Underside of the laser head will have a key switch, this mounted on a plate to cover up all the bolt holes needed to hold the mirror / dichroic mounts in place.

The u.p will be fixed to the rear face of the driver tray
The head is 48.5mm dia x 68.0mm (excluding the driver tray).

..............well that's the plan, I'll update the thread as I make the parts / agony of failure / extacy of sucess etc.

14th Sept.
Made some progress today:-

Machined the mirror and dichoic mounts, they are 10mm tall x 8mm wide.
The small square the mirror fixes to is 7.0 x 8.0mm and has 4 M2 adjustment screws with 1 grub screw that acts as a pivot.
the mirror mount is machined on the end of a 12mm bar, both the mount and square adjuster thingimabob in one go.
The are left joined by a wafer thin strip which is cut off with a scalpel and a small fine to remove the burr.
The M2 holes need tapping and bolting together - the hard work done on these and I'm happy.
Photos show the setup and AA battery for scale.

Also machined most of the laser head, I'll post a photo when its finished.

Update 15th Sept:-

Photo of the head, just the module holes and wire access holes to machine in the end above the driver tray and skim the front face where the beam will exit......oh and tap the M2, M2.5 and M3 holes and it will be finished.
Now working on the underside cover that the key switch will me mounted to.

Bit more progress - more holes !!!!! :-)
Centre hole at top for joystick wires
top two outside holes for LCD wires
3 large holes - no prizes for guessing :-)
2 holes between 12mm module holes are for the cable from key the switch.

Made the joystick insert. This clamps the pcb in the recess, a small flat button will press onto the joystick to cover the central hole.

Completed the design of the next part, the underside cover which will hold the key switch and also cover up all the holes and bolts that hold the mirror mounts in place.
The large hole in the centre is for the switch and is M12x1.0 - overall length of the cover is 57.0 x 34 wide.
Should be interesting if it ends up looking anything like the model !

Bit of progress while waiting to sneak some machine time....
Drafted the PCB. Uses a ATMega328, connectors are, PWM to drivers, SPI to LCD, Joystick, in circuit programming header etc, based on my breadboard hacked version.
2 holes at the bottom are for fixing the board to the back of the driver tray.
The transistor lookng device (above the right side mounting hole) is a temp sensor that will be burried in the heat sink so that the running temp can be displayed on the LCD, this will also give the posibility of automatically lowering the power of the lasers if the temp gets to high.
I've also added a potential devider to measure the battery voltage - haven't tested this on the bread board, but should work.
The silk screen needs a bit of tidying up.
Looks good so far, but will it work? Only one way to find out :-)

Assembled one of the mirror mounts today - incy wincy little things.
The mount pivots on the central screw and can be adjusted in / out to give Z adjustment.
X Y adj using the 4 outside screws - looks like it will work.

Made the key switch cover today - came out great.
I've just got to tap the hole M12x1.0 for the switch and it's complete.
.....onwards to the LCD cover now.....