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TTL on a cheap Chinese driver troubleshooting

Posted by jdargot 
TTL on a cheap Chinese driver troubleshooting
July 11, 2018 04:51PM
Hello, I recently bought a Chinese laser for my first laser cutter conversion from a 3D printer. The driver has clearly marked pins for the TTL input and the +12v. After researching, it seemed like the most common setup was running the 12v port to the power supply and connecting the TTL pins into a port that has PWM (I used the classic D9 port).

Testing the laser, however, I would plug the board into the 12v supply and the laser would instantly turn on. The TTL port made no difference to the laser.

I understand this is a common issue but everyone seems to take a different approach.Sometimes it's the voltage, sometimes you need resistors, sometimes it's a wiring issue or a bad board. Knowing me, I could have just missed something really obvious.

Does anyone have advice on the next steps I should take?

Thank you
Re: TTL on a cheap Chinese driver troubleshooting
July 12, 2018 04:32AM
For safety reasons you could add a relais between 12V and laser-driver ( add a keyswitch for total peace of mind). That way you can software-control when the laser driver get's powered.
VDX
Re: TTL on a cheap Chinese driver troubleshooting
July 12, 2018 06:23AM
... this chinese drivers are not really "standardized" - they can behave randomly ... but could be, it's meant to short the TTL input to GND to get the laser OFF ...


Viktor
Re: TTL on a cheap Chinese driver troubleshooting
July 12, 2018 10:28PM
Supply the laser driver with its own 12V power supply

Trigger it with TTL connection

Pin 11 or 12 of arduino can be set to PWM TTL

M3 laser ON M5 Laser OFF

M3 S(1 - 255) with set the PWM and power out of laser

there may be a switch on driver for TTL or continous trigger

confused smiley
Re: TTL on a cheap Chinese driver troubleshooting
July 13, 2018 02:19AM
Thank you everyone for the advice.

o_lampe, that is good thinking and I may do that eventually. But I would like to figure out the driver a little more and consider other solutions first.

cozmicray, I did everything you suggested up until pin 11 or 12. I have been using pin 9 instead because it is fairly easy coming from the cooling fan and should still be PWM capable. Are 11 and 12 any better or is it just preference?

On another note, I realized I should have adjusted the driver using a multimeter and the potentiometers before testing. Who knows what chaos might be going on since I don't know the voltage going through the thing. I'll make those adjustments and see how it goes.
Re: TTL on a cheap Chinese driver troubleshooting
July 13, 2018 06:00PM
Just a matter of making G-code control the right pin

see

[jtechphotonics.com]

using D9

M106 S255 = Turns the laser on at full power
M106 S0 = Turns the laser off
M106 S127 = Turns the laser on at 50% power
M107 = Turns the laser off as well

confused smiley
Re: TTL on a cheap Chinese driver troubleshooting
July 23, 2018 12:21AM
Okay, so I checked the driver with a multimeter and it appears that the TTL makes no significant difference on the output to the laser.
I'm considering just getting a new driver but I feel like there must be something I am missing.

By the way, here is a link to the laser and driver. Has anyone worked with these kinds in the past?

[www.ebay.com]
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