Laser TTL

[TFMvdBroek]

So i've just got a 5.5W blue laser module for engraving/cutting.
It has 3 pins. V+, GND and PWM.

I thought that the laser would turn on/off depending on the voltage on the PWM pin.
But if I put 12V on V+/GND the laser turns on full blast.

How can I control the output power?

 

[chloderic]

Could you please post a picture?

 

[paul1598419]

With TTL logic you only have the option of off or on. Most are controlled by the PWM duty cycle to provide more or less power to the surface you are trying to engrave or cut.

BTW, TTL is +5 volts on and 0 volts off.

 

[TFMvdBroek]

Could you please post a picture?

It's this one: https://www.aliexpress.com/store/pr...graver-part-DIY-Laser/704555_32958503779.html

 

[TFMvdBroek]

With TTL logic you only have the option of off or on. Most are controlled by the PWM duty cycle to provide more or less power to the surface you are trying to engrave or cut.

BTW, TTL is +5 volts on and 0 volts off.

Ok but if I put no voltage on PWM pin it should stay off right? 5V on PWM pin doesn't change the result.

 

[paul1598419]

You will need to feed a PWM signal into the PWM terminal with respect to ground. By varying the duty cycle, you will get longer and shorter pulses, which sort of controls the power being sent to your project's surface.

I can't say for sure about this particular laser if no input will produce no lasing. Most are built that way, but not all. You may have to apply a 0 volt, or ground the pin to turn it off.

 

[chloderic]

So it is as Paul said, 5v on 0v off normaly, i have some where it is inverted or you can invert by a swich. To use something like a powercontrol for this laser you have to trigger a ttl signal , the driver is ttl.

 

[TFMvdBroek]

You may have to apply a 0 volt, or ground the pin to turn it off.

This was the fix. Putting GND signal to PWM turns it off. Lovely

 

[chloderic]

You see ... ask Paul .....

 

[paul1598419]

In case you don't know, PWM stands for Pulse Width Modulation. The idea is to have a pulse train at a certain frequency and by changing the length of time of the positive going pulse, you can have the laser on for a % of the period of the cycle. This will give you something akin to changing the power of the output especially if you choose a frequency of 15 KHz or better.

But, if you are using this to engrave and you have your laser position controlled by servos, you should be able to ground out the input pin through a transistor to turn it off as the servos move your laser in the X and Y directions. That way you can program the the engraver to do any sort of picture you might like to have.