5W Laser - Mini-Rambo - Assembly Pics

Hardware: mini-rambo

Software: Marlin

Laser: 450nm 5W Laser Engraving Module Blue Light Marking Engraver With TTL Modulation Link (https://www.banggood.com/450nm-5W-Laser-Engraving-Module-Blue-Light-Marking-Engraver-With-TTL-Modulation-p-1218494.html?rmmds=search&cur_warehouse=CN)

Thanks - Leo, David, Ryan, Ted G, Jeff, etc… I read all of your comments and posts about lasers and I learned a lot. It gave me the confidence to go ahead and give this a shot as a non-engineer, coding type guy. In the vein of, “I’d rather be lucky than good”, it all worked - the very first time, thanks to the team on this forum.

Pics of the laser and setup first then a breakdown of a few things I learned along the way.

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Things I learned:

  • Power. I thought this was going to be a bigger issue than it ended up being. Because my laser is 12v it was pretty much ‘plug and play’ into the Fan 1 connection on the mini-rambo. NO ADJUSTMENTS were needed to the firmware or pins…which was awesome.

-gcode. The J Tech plug-in for inkscape works. I was quickly able to get text and simple outlines into executable gcode. Still working images and raster…but that’s what the forums are for!

-Laser mount. There wasn’t a mount that fit a 33mm x 33mm laser on Thingiverse so I had to dive into Fusion 360 to make my own. It took a minute but it was a great learning experience The new ‘Mesh’ feature in Fusion 360 allowed me to take the DW 660 Lower Mount designed by Ryan and remix it to make it work for my laser. Its simple and it just works - which I like! It takes advantage of the machine screw holes on the back.

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Initial Burn:

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This was really fun and I learned a lot. I continue to be appreciative of this site and everything that Ryan is doing to help others do awesome things.

Have a good one!


Ran out of room for photos on the first post. Here are pics of the laser mounted. I used the DW660 mount to zip tie the driver.



Great post!

12v ttl!? $116 +$5 shipping already in the US. Great find, I think the $21 is worth not having to alter the firmware, not setting drivers, ordering from multiple places, and getting more power than the previous recommended laser. I am going to go broke buying attachments!

One huge advantage when you go from etching to trying to cut something is compressed air, or similar right at the cut site. I have a pump from the Berd Air that I am not using, I think that would be pretty good for this.

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Are you sure it is 12v ttl? Have you used it at full power, it say 5V ttl? So you might have issues above 41% power (s106).

Are you sure it is 12v ttl? Have you used it at full power, it say 5V ttl? So you might have issues above 41% power (s106).
I'm not 100% sure...still new to this. I have run it at S 10, at S125, and S255...with no issues. I don't have the right gear to check the output to the laser from the driver...it's probably 5V, not 12V but I'm running it straight from the Fan 1 output and am able to control the power. The power supply to the driver is 12V 5Amp.

Definitely interested in the pump


Interesting. I can’t find any info. One of there other lasers says 5vttl 12v pwm, since you are using PWM that must be the case. I want to grab one but I hate going in blind on a $120 part.

How do you have it wired, power and the positive side of the fan port? Any idea what the other port is for. I am getting the feeling the one you are using is PWM, and the other one is ttl. Sorry for a million questions I just think a lot of people would be interested in this or some of there other lasers as well.

That is how I have it wired. On the Driver I’m going into the ‘Power In’ connection, and on the mini-rambo I’m matching the +/- on the Fan 1 Output. Here are a few pics:

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I’m not using the ‘Yellow’ wire coming out of the driver, and that isn’t impacting my ability to control laser power. I will try a grayscale pic to see how that goes and let you know.

quick results on some 1/4" plywood. To your earlier question - I’m not sure what the other output (PWM/TTL) is for.

The circle was max 90%, min 20% power in lightburn (free trial) Power was too high, went pretty deep.

The box was max 70%, min 20% power in lightburn.

[attachment file=“grayscale test.png”]


Can’t argue with the results – which look good – but you are modulating (PWM) the power (12v) to the laser with the D9 fan output. This is the way lasers without TTL (or other) input are usually controlled. I have an LCheapo laser – the one in the ruler engraving video – that is controlled that way.

Yours is actually designed for constant 12v power application and a separate TTL (5v) PWM to control the intensity. You’ve inadvertently discovered that the unconnected TTL input “floats” high – interpreted as ON – and then the 12v power modulation achieves the desired result… just like the LCheapo and with only 2 wires!

Since yours appears to work nicely, I’d probably leave it that way… the floating TTL input probably isn’t best but it appears to work. Mine is the same controller and I tap constant 12v from the RAMPS power and then pick the remapped D9 fan output from pin 44 on the RAMPS for TTL compatibility. Since it’s still the fan control signal, M106/M107 is used to control the laser intensity.

Good work, Cap! – David







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Yeah, it’s like you’ve got the knob set to 100% and you’re turning it on and off fast.

The results do look good.

Dave - I knew that you’d have the answer! I don’t know that I fully understand it - I’m with Steve, mind blown - but it does make sense. In your experience what would be the benefit of utilizing TTL vice working the PWM route I’m currently using? I thought hard about buying a RAMPs setup to do what you described with pin 44 because it was a proven method but decided to give the mini-rambo a shot before I did so.

Have a good one

It works on every board, it is just a pin change. There might even be a way to do it without flashing the firmware. I will try and find it but I think you can specify what pin with the M106 command somehow.


I did a lot of searching last night about this. The advantage of ttl is you will get 255 levels of power very accurately. With PWM you will get a lot of levels but it is driver and laser dependent most start at level 20-30 and do not ramp up linearly in power. The way you are doing it isn’t really even PWM (yes and no), but you will get even less range than real PWM.

They way you are using it you can dither your art to get a better range but you can see in the wheel you don’t actually have any gradual fade out, it is basically just off and on.


I believe the instructions are there for changing the mini-rambo pin, and if you look into m106 commands I think that is an option as well. You should get that ttl pin hooked up and you will be amazed at what that laser can really do.


Heck, I forgot Marlin now has Laser control built in…Maybe it is time for some firmware updates.

Pew pew pew (sorry, I’m just a big kid).

The laser stuff is a little muddled with spindle stuff too, so you’d be killing two birds with one stone if you can get a set up for lasers and your PID controller in one version.

I think M106 has some problem with buffering, like it doesn’t go into the planner, or something. One of those pins was special and it shortcuts the planner and just turns it on, even if it hasn’t finished the moves to get there. Actually, that might be the fan pin? Or maybe the fan is the only one that goes into the planner? I’d have to look at the M106 code.

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Yup, just glanced at it. For the Rambo…two birds, the mini’s current laser pin is on the lcd header, there is another pwm pin on H3 Rx or TX. Better double check if we can actually use that pin.

That gives us M3 commands instead of m106



I don’t use the mini-Rambo board (yet!) so you need to listen to Ryan, etal… and use the pins it provides for this. Please don’t buy a RAMPS board just for this. I think Ryan explained the TTL PWM thing pretty well so let’s hang loose and wait until we get definitive info on which pins to use. Then you can hook it up properly, without fear of breaking something =8^)

– David

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Ryan/Jeff - thanks, I’m ready to hook up the TTL wire once we figure out where to plug it in. Appreciate the info on TTL vs PWM, very helpful. I ‘dithered’ the circle and ‘grayscaled’ the box for the test last night. Probably should’ve mentioned that.

Dave - thanks, appreciate the advice - I’m hopeful the team will find a solution. The mini-rambo has been a great board, I’ve had zero issues with it. Now that I know this works though I’m going to have to build a new machine, I gotta have both!

It would be nice if the 5V pin would just accept the 12V signal. Seems like a low part count to accommodate that for a high impedance input. Oh well, no one making these control boards is ever going to read this…



Again, no specs. Or are you saying that we should make a board that supports this???