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Can a laser driver with TTL control laser intensity?

Posted by ianmcmill 
Can a laser driver with TTL control laser intensity?
September 05, 2015 11:48AM
Hello two years ago I built the Frankenstein Laser Engraver from trash. Today I am more into 3d printing and RAMPS or printrboard boards but recently found my old laser again. It uses this TTL driver [www.aixiz.com] on which the current is set by a potentiometer. I made a laser shield for an Arduino Uno myself. Now I wanted to attach this laser driver to an RAMPS or printrboard. Now jtechphotonics offers a kit with driver and laser and everything you need and he controls the laser's intensity with PWM.

Is it possible to control the intensity of the laser with the driver board I have linked here, too?


Blog: Capotexl
Filament Factory - How to build your own cheap filament extruder
Frankenstein Laser Engraver
VDX
Re: Can a laser driver with TTL control laser intensity?
September 05, 2015 02:07PM
... the effective engraving 'power' of the laser is averaged from the ratio between the ON-time and the OFF-time summed for all pulses.

I'm mostly engraving with current set to max and then only changing the pulse ON-time between 4 and 400 microseconds with constant distances between the single spots/pulses in a line ...


Viktor
Re: Can a laser driver with TTL control laser intensity?
September 06, 2015 06:11AM
Hey Viktor!

How do you set the pulse ON-time? Isn't this generated by plugins for let's say the inkscape laser plugin automatically ?? I don't know anything about changing pulse timers...


Blog: Capotexl
Filament Factory - How to build your own cheap filament extruder
Frankenstein Laser Engraver
VDX
Re: Can a laser driver with TTL control laser intensity?
September 06, 2015 09:02AM
... my laser-driver is built around an ArduinoPro-clone, which generates the pulses.

It's like feeding a pulse signal from the printers electronic (or generic CNC-controller) to the laser-controler, which on his own redefines the pulses to create precise ON/OFF-times for the laser, which can be changed per potentiometer or analogue voltage to get different engraving powers with the same pulses from the CNC-controller ...


Viktor
Re: Can a laser driver with TTL control laser intensity?
December 02, 2015 03:05PM
I recently attached the laser driver directly to the fan connector (D9 IIRC). You can control the power from 0..100% in repetier or use M106 S0..255 which has a frequency of 7Hz. You'll need to move very slow or you get non connected dots smiling smiley My laser is recovered from a 16x dvd burner, I drive it at 400mW. Cutting is very slow so I leave it at full power all the time, just change feed rate for different materials.
The setting of 1% is very handy to position the laser on the material, it's not too bright for the eyes on black objects.

I had some problems with an instructable tutorial, the linked gcode extension for inkscape didn't work for me. I modified/hacked the gcodetools myself and that works for me. I just copy/paste it into repetier gcode editor and start the 'print' job.


--
Kind regards
Imqqmi

New blog:
[makercentral.net]
VDX
Re: Can a laser driver with TTL control laser intensity?
December 02, 2015 03:40PM
... 7Hz is not enough for proper laser-engraving - I'm using up to 100kHz and up to 150mm/s moving speed with a small commercial CNC-controller and up to 300kHz and 400mm/s with an ArduinoDue and RADDS ... and wish, I could drive/pulse even faster winking smiley


Viktor
Re: Can a laser driver with TTL control laser intensity?
December 02, 2015 05:59PM
I'm going to do some more improper engraving then tongue sticking out smiley


--
Kind regards
Imqqmi

New blog:
[makercentral.net]
Re: Can a laser driver with TTL control laser intensity?
May 22, 2018 04:04AM
Hi,

i'm trying to run a laser with Arduino DUE + RADDS as you. I have some problem to regulate the laser. How do you connect the laser to the board? Which command do you use to control it?

By the way, i'm using repetier firmware.

Thank you very much.

Have a nice day,
Gabriele.
VDX
Re: Can a laser driver with TTL control laser intensity?
May 22, 2018 04:29AM
Hi Gabriele,

I've connected GND and the extruder CLK-pin to the laser controller - so every clock-pulse, meant to step the extruder motor, will output a laser pulse.

For changing the power there's a trimpot with 0-5V for 1-100% and a reset button, to restart the laser controller, which only while "reboot" is checking the trimpot-voltage.

The pulse-ON-length, set by the trimpot-voltage, is between 5 microseconds for 0v to mostly 300 microseconds for 5V 0r "100% power".

The "real" or effective power is too defined by moving speed while pulsing, what is set in the firmware with the "extruder pulses per mm" value ...


Viktor
VDX
Re: Can a laser driver with TTL control laser intensity?
May 22, 2018 04:35AM
Quote
lordgabriele
...Which command do you use to control it?

... with "e-pulses per mm" set to 1 and the extruder CLK output, it's as simple as "G0 X100 Y300 F6000" to move without laser -- and then "G1 X200 Y300 E4000 F2000", to engrave a 100mm long line with 40 pulses per mm ...


Viktor
Re: Can a laser driver with TTL control laser intensity?
May 22, 2018 04:47AM
Thank You! I Will check your solution in the evening!

Gabriele
Re: Can a laser driver with TTL control laser intensity?
May 23, 2018 04:59AM
Yesterday evening I played a bit with the laser.

At the moment I have connected the laser control wires to pin 25 and to ground.
So I don't use yet your solution with EXXX command and stepper clock.

The problem now is a strage behaviour of the laser.

It should turn on for any G1/2/3 command and turn off for G0 command.

Instead, it turns on correctly with G1/2/3, but if the Y coordinate is different from zero it turns on also with G0 command. In other words, if the printer head moves along the X axis it works correctly, but if I add a Y component it starts to turn on also with G0.
When the head stop the laser turns off correctly.

I tried to connect to pin 29 to try another pin, but with 29 i didn't succeded to control the laser (probably some bad configuration).

I don't know what to think sad smiley
I want to spend another bit of time in resolving this issue, after that i will migrate to your solution hoping to bypass the problem

Bye, Gabriele.


P.S.: what software do you use to generate Gcode with the EXXX component?
VDX
Re: Can a laser driver with TTL control laser intensity?
May 23, 2018 02:47PM
... it's running with normal 3D-printing software, which calculates the E value for the active "extruder" automatically, synchronized with G1 movement and any displacement in X and/or Y.

In detail, it's a variant of Pronterface, which I've modified for some other tasks, but the E part is the same as in the original version ...


Viktor
Re: Can a laser driver with TTL control laser intensity?
May 24, 2018 04:42AM
Thank you for the hint!

Bye,
Gabriele
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