Laserprojector en: Unterschied zwischen den Versionen

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[Deutsche Version]

laserprojector Release status: experimental [box doku]

Description	projector using laser and 2 mirrors for deflection
Author(s)	siro
Last Version	0.2

DIY Laser Projector

Concept : Build a laserprojector as easy as possible

Übersicht

Max. Resolution:256x256
Refreshrate:30Hz
Colors:1 (blau)
Colordepth: 256 (8-bit)
Interfaces: RS232, ??
Reflectionunits:2x Mirrorwheels, Asyncronmotor + DC-motor
used Controllers:ATmega169 + STM3210xx

Basic Idea

An Atmega controlls 2 fast motors, checks keyboard input,controls GLCD and Power-Supply.
On each motor is a mirror-disk spinning to deflect the laserlight.The first mirror deflects the light only in the horizontal layer, the second one deflects light on the vertical layer. I'm going to modulate the laser diode to draw images.

Syncronisationunit:

obsolete
Detects position of the laserbeam [eagle Dateien im labor-svn]
Better use a impedanceconveter, instead of voltage divieder.

schematics of syncronisationunit
SMD-Board of syncronisationunit

Description

TODO Die LEDs leuchten auf den Spiegel, wodurch das reflektierte Licht auf die Photodioden fällt (nicht kritisch welche), wird differenziert, rauschgefiltert und verstärkt. Am Ausgang des OpAmp schneidet eine Diode die negative Spannung ab. Ist diese groß genug, schaltet der FET (BSS123) durch und zieht die Output Leitung auf Masse. Am anderen Ende der Leitung muss ein Pullup-Widerstand sein, der den Strom auf unter 100mA begrenzt. Versorgungsspannung: 3,7 bis 15 Volt (empfohlen 5 bis 12 Volt).

Syncsensor

Two small IR-LEDs are emitting light onto the spinning mirrors. The deflected light changes the current at the "fototransistor".

Saftyunit

obsolete
The Saftyunit has to detect, that both mirrors are spinning fast enough, to prevent damage to anything in the laserbeam. The saftyunit cuts the laser power as soon as anything shows abnormal behavior.This is a class 3 laser, able to burn wood/paper/flesh even in a few meters distance !

Controlunit

Connected to the controlunit are GLCD, Keyboard, Horizontal-Motor, powersupply, i2C

schematics of Controlboard
layout of Controlboard

Horizontal mirror

I received a "Laserunit" out of an Epson printer doing 24000 rpm with 7 mirroring sites. 24000*7/60 = 2800 deflections per second.

Laserunit made by Epson

Lasersupplyunit

This circuit is able to regulate the current going trough the laserdiode. Its able to modulate the beam up to 1Mhz with a 0/3,3V input signal. The output is a rectangle modulated current with an adjustable offset and max. current. An OpAmp is missing in this circuit.

schematic of lasersupplyunit

Imageconversionunit

TODO

Laserdiode

WARNING !
This is a class 3 laser, able to burn wood/paper/flesh even in a few meters distance !
Wear security goggles !
I'm using this laser to project an image at a very big surfaces ! This prevents serious eye damage when looking at the projected point!
Do not look into the beam!
1000mW (1W) Laserdiode 445nm blue 5,6mm