Laser X/Y scanner in development

[gyrodryve]

This is my fourth post, and will be for those who want to get their hand dirty with electronics and build their own laser scanners. I'll give the 1.2.3 on it, but it'll involve a soldering iron, a decent (100mw+) laser, and lots of tinkering. The gizmo will include:

Full schematic available to everyone
Full source (aka change the code to suit your needs)
Runs on basic, easy to program
Full calibration - set the unit up from the LCD to suit your servo's and laser head
Power adjustment of laser to suit venues
Control of TTL lasers
LCD screen - either locally or remotly mounted with controls
Beat trigger
NVram so it doesn't need to be force fed its code every time its powered up
Cheap servo's - $10 us on fleabay
Simple electronics - a monkey with a blowtorch could build it!

The circuitry is basically a simple DAC linked to a LCDX (details soon) board that has 16 I/O's, a keypad input and a uC - and it programs in basic - remember the commodore 64? easy to learn and hard to forget.

Total outlay (less enclosure parts) should be ~$100 less laser, for automated music controlled (or auto, manual) beam effects including:

Circle
Square
Triangle
Liquid Sky
Scatter beam
Diamond
Rotating square/triangle
Bouncing Sky
Poloran scanner (borg from star trek Voyager)

Cant go on - still need to finish the rest of the sequences and run them thru the simulator.

Need input for the input - Shall we have a keypad or buttons left of and right of the 4 lines on the 4x20 display? (and a big red execute button below)?

 

[geert01]

cool stuff, keep us posted

 

[SenKat]

This is exciting stuff here ! Are you going to offer a "kit" to purchase from you, or make us all go on scavenger hunts ? ;D I am moving this to the Scanners and Shows topic area - DEFINITELY keep us all updated (or just me....I am not picky ! LOL !!!) THAT is the reason I got into this hobby - is to make a show device ! So - just to put the cart before the horse, would the servos be able to be replaced with galvos at a later time ?

 

[FokoF]

COOL ;D Can't wait to see what it looks like.
Keep it up!!!

 

[gyrodryve]

Senkat thanks for moving this - I was not thinking

No I will not be offering a kit but the code and schematics will be free and easy to build on prototype board. Most expensive part will be the $70 UC with built in LCD.

You will:

*be able to put on a cool beamshow with the device
*be able to monitor everything / control it all from a local/remote LCD with buttons
*control your lasers power from the unit
*Kill/restart your laser in an instant (for emergencies)
*Test lasers of unknown power levels by hooking them up

You will not be able to:
*take over the world
*blow a hole in the lunar satellite
*turn your 5mw pointer into a deathray/lightshow
*elecrocute yourself unless your REALLY stupid
*hold me responsible if you stuff your property
*ask me questions on making high explosives (forget it - I came here for the love of lasers, not firecrackers!)

The rest is free/cheap (e.g. the DAC is free as a sample from Maxim semiconductor), the servos are cheap off ebay. It is intended for a beginner/intermediate in laser / beginner in electronics to wow their friends with. It is never designed to run galvos (will probably cook them).

You (the builder) will just need to:

Make some servo mounts (chop up a cheap jaycar alu box and drill some holes),

Solder the works together (pretty simple - no more than 20 wires to link up)

Take some measurements if you want some power control - $10 fleabay/tandy meter essential (From the beginning, not just for this part)

Know the ass end of a diode from the other end

Have some common sense. I'll give full SxS instructions.

What I wont teach you:
How to turn on your soldering gun, and which end to hold onto.
What the big dial on your multimeter means
When and when not to provision your saftey glasses for your particular laser (you do know when to wear them right!)
How to use super glue and a bubble level
How to build a 12 volt power supply.... You'll need a 3A 12-18 volt supply to run "the guts"

Oh yeah what are those machines called that do stuff like:

Scenario:

Two bottles hang upside down, one contains scotch, another cola, and a trapdoor between contains ice. A marble rolls down a slope, ignites a burner that burns up a piece of paper. A laser fires onto a photocell and exactly a nip of scotch is delivered to the glass, before the chemical on the surface darkens, stopping the flow of scotch.... Same goes on (zany stuff) until a stiff scotch and cola is delivered to the glass.

Completly off topic but I need to know what those zany machines are called - no use, but do the job the long way

 

[Daedal]

Good stuff Keep us posted and good luck. If you need any help with anything let me know

--DDL

 

[gyrodryve]

Deadal - thanks for the support - I want to get this project off the ground soon - will be ordering the uC soon as the mob who makes it gives me some answers and the bank balance says ok. I still need to test my DACs, get a shitty pc for programming (I use macs) and need to work out how to make it control the forums lasers without blowing out pump diodes (the power control feature). Also want it to sense juice so it can auto reverse in case some silly twit reverse connects their pot and as they're cranking up the power, the light level drops, so it say "I see a drop in power, who wired up the pot wrong? I'll invert output!"

BTW your sig reminds me of earlier this evening when the bouncer pointed his greenie at me. I had my 350 mw gizmo with me. His friend (the girl on security) said "go on, zap him, I'll stand up for you). He was wearing all black. I said "luv, this is 1000 times more powerful than his weak pen laser" and gave her a demonstration. We all knew one another and the guy knew I carried a big ass laser around. Was fun.

 

[Daedal]

HAHAHA... that's really cool

Also, about the wiring things with opposite polarity, this is going to be quite fun You can stop reverse polarity using a diode(1N400X) and then you wouldn't need to worry about the reverse polarity, the circuit simply won't work. As about ramping up the power to the circuit... I have several ways that I can do that through software. I did it once before, but never did use the ramp feature, only the ON/OFF. I was controlling 2 lasers through my PC though If you're thinking of using a micro-controller, I have the thing that writes the code onto the uC myself, and have done a couple projects here and there with it. It would be cool to see it help control a laser though...

Hope to get this up soon
--DDL

 

[pseudonomen137]

Interesting project, but I'm a bit confused as to what you mean by hooking up the pot backwards. The pot is basically a variable resistor, stick it in either way and it works the same. Basically serves as a variable damper to the magnitude of the voltage, whether that voltage is positive or negative.

As Daedal said, if you're worried about anything being hooked up reverse, just stick an adequate diode in there.

As for this power control idea, why not just use a laser with a driverboard that handles analog modulation?

Anyway, some aspects of your project seem similar to Boomdog's work, so if you haven't already checked it out this link may interest you:
http://www.skyfirelasers.com/boomdog/byoshow.php

Also, what are you planning on using for mirror actuators in the scanner? If the "$10 eBay servos" were that, I'm sorry for the bad news but I don't think that's going to work. Unless you're going to use real galvos they're gunna be far too slow and I can think of a few other potential problems. If cheap is your goal, pehaps you should look into stepper motors (I think that's what Boomdog used)

Good luck! You definitely have a lot of work ahead, but it'll be interesting to see what you come up with - pro lasershow stuff is FAR too expensive.

 

[Things]

that's really cool, i want to see it going as well! YAY someone bought my green laser show, $160 in my pocket for the RGY laser show WOOHOO

 

[chuckknight]

How will the uC be interfaced? Is it something we could use a PC for? I have extra PCs lying around...and the additional programming capabilities could be amazing.

-- Chuck Knight

 

[gyrodryve]

pseudonomen137:
With regards to "hooking the pot backwards" the pot controlling the laser power is a digipot - its a pot on a chip that can be controlled by digital signals instead of the analogue hand moving the wiper. They may be a little confusing for some members to wire up - getting the end that has the lower half of resistance with respect to the wiper the right way around with respect to the lasers original pot would be one of the harder bits to set up. I will make it easy and tell the builder to set the power pot up with a multi meter first. They work by pulling an enable pin high, then feeding pulses into either a CW or CCW pin. This increases or decreases the. wiper position.

The outputs are RL, W and RH being resistance low end, Wiper and resistance high end.
Think of it as a volume control. As you send pulses into CW, with the enable pin high, the volume goes up. Conversly feed pulses into CCW and the volume goes down.

The scanners Boomdog used were steppers. These are the same thing. I dont know why I was calling them servo's

I have the same set of steppers that Boomdog has

Chucknight: I dont see why not - we could incorporate some code into the uC to have it listen to the serial port and you could send it control commands over that (it has a built in DB9)

Deadal:
Laser power will be set by a digipot - Once you've constructed it, you get a cheap pointer first (for testing) and set your lasing threshold (Imin) and Imax in the uC's memory (it will write these values to eeprom so it doesnt forget). On initilization, and before starting up the laser (solid state relay) it'll read these values into ram, set the power pot to minimum, then wind it up to Imin and then enable user laser control.

 

[Daedal]

That's exactly what I did...

I had it listen to a serial port for data entry, and it used a digipot to control the laser output

--DDL

 

[gyrodryve]

Just ordered some sample digipots from maxim. Non volatile so if you dont want laser brightness control, but want to adjust it occasionally, these will keep their value indefinatly until adjusted.

Means one less value to store in eeprom, plus one less routine for those who dont want power control in the display routines.

 

[pseudonomen137]

Now this project is starting to get interesting (sorry for my mistakes above). I would still suggest you look into lasers with analog modulation input though for varying the power though. Trying to power a bare diode directly with a current setting from the microchip... would be extremely unconventional at best and sounds pretty risky.

BTW, do you have any estimate on how fast this control would work? I think Boomdog faced some speed-related limitations, and it sounds like you're trying to implement more features per cycle. Would everything be done through BASIC, or perhaps some stuff could be done lower level in the interest of speed?

The DB9 interface sounds particularly interesting, but even more interesting may be an ILDA DB25 interface if possible (standard control for pro lasershows.. usually stuff in the $10k+ range range. Has lines for modulation of RGB, galvos, etc).

And last question (for now ), any idea how many poles on the steppers?

Thanks for putting up with my rambling! This sounds like a project with a lot of potential.

 

[rog8811]

*thread added to favourites list*
rog8811