5W+ Laser

Leo69,
Thanks for posting the reply. So by “full featured” I think he means having an easy way to set and read the max current. Unfortunately they are from Russia and Germany and will take a bit to ship to the US. It would be nice to also find a switching regulator.

Yes TTL just means the logic level. A PWM signal generically is a digital signal that must have a logic level specified and is used to control a driver transistor. Again as I mentioned above, the X-Drive application info is using that TTL input to turn on and off the laser driver at a 5KHz rate with a particular on ratio. This will vary the average output power and give us gray scale burning. The slew-rate capacitor will need to be removed for this to work.

Steve

Yes, PWM is just switching on and off really fast. Seller recommends 1khz switching frequency. The output power is fixed but can be adjusted via a different resistor or add a trimpot. If you wanted to get fancy you could also use and I2C trimpot and a little code work in marlin to set the output power with g-code.

KRavEN,
For the SDX V3 Super XDrive where is the resistor that adjusts the current? I don’t see it in the DTR’s Laser Shop page. Where did the seller DTR specify a 1kHz PWM frequency? In a personal message? DTR’s page https://sites.google.com/site/dtrlpf/home/flexdrives/x-drive specifies 5KHz.

Would be nice if they supplied schematics for these things. It’s not nice dealing with a black box.

Thanks,
Steve

Marlin firmware uses the analogWrite function to drive the fan output , which uses 8-bit PWM at 490Hz frequency. Firmware mods are possible that can increase the frequency and/or the resolution by reconfiguring one of the 16 bit timers and writing to the OCR register directly instead of through the analogWrite function. The increase in PWM frequency doesn’t really make a difference with laser engraving from what I’ve seen but the increase in PWM resolution does help with high powered lasers.

KRavEN, For the SDX V3 Super XDrive where is the resistor that adjusts the current? I don’t see it in the DTR’s Laser Shop page. Where did the seller DTR specify a 1kHz PWM frequency? In a personal message? DTR’s page https://sites.google.com/site/dtrlpf/home/flexdrives/x-drive specifies 5KHz.

Would be nice if they supplied schematics for these things. It’s not nice dealing with a black box.

Thanks,
Steve

I did an inquiry on eBay and that was in his response. I know that the output is set via resistor because some of the driver pics show a trimmer but he said in an Amazon review or question that they don’t have them anymore and are set via resistor now. He also sells the same driver in output from 2amp up to 4.5amp in .5amp increments. Once I get mine in I’ll trace it out and build a schematic for it. These things aren’t super complicated so I don’t think it will be difficult.

Marlin firmware uses the analogWrite function to drive the fan output , which uses 8-bit PWM at 490Hz frequency. Firmware mods are possible that can increase the frequency and/or the resolution by reconfiguring one of the 16 bit timers and writing to the OCR register directly instead of through the analogWrite function. The increase in PWM frequency doesn’t really make a difference with laser engraving from what I’ve seen but the increase in PWM resolution does help with high powered lasers.

I’m using a MKS SBASE board with SmoothieWare firmware for my MPCNC. I think it’s a better fit because it has support for CNC, laser, and 3d printing and DRV8825 stepper drivers. It also has PWM available on a bunch of different pins that support PWM frequencies well above 5Khz.

Wow. Just spent a half hour reading about the MKS SBASE. It looks awesome! This will definitely be my next upgrade. Thanks for posting

Crazy timing. I just asked one of my vendors for some of some of those sbase boards. But I was trying to get the one with the larger drivers though. Gotta love the digipots and I won’t have to sit here assembling the ramps sets!

If you want to start a new thread for it I can provide my config file for MPCNC. I’m just about done with my build now. Finished assembly and got X and Y moving last night.

MY todo list:

  1. print and attach the end stops
  2. drag chains
  3. laser mount and router mount
  4. remote speed control for the DWP611
  5. design and print enclosure for the MKS SBASE
  6. raspberry pi, octoprint, camera

I was reading that smoothieware currently has no support for laser engraving, only laser cutting, but it will be implemented in the future. I wonder if we can implement through the fan control in the meantime, like we do with marlin? I’ll have to download this firmware and start studying it. A dedicated smoothieware thread might be a good idea. I think interest in the 32 bit platform will definitely pick up.