I've got @Egon-Net's digital-to-analog board for use with a (non-PWM) part cooling fan with the Duet 3 mini 5+.

I finally found the time to hook it up, but am looking for a nicer way to the fan speed control. The thing is:
Egon's board makes 0-255 PWM turn into 0-12v. My fan only turns on at 4.5v. I configured the minimum speed to be 100 PWM (with M106 L100).

When turning the fan on and setting it's speed, I'm noticing the following:
1-40% = constant 4.7v
40-100% = 4.7 - 12v

I would however like it to behave like this:
1-100% = 4.7 - 12v (I.e. 100-255 PWM)

Is this (currently) possible in some way?

That would be too bad. Is this something that could be implemented in a future release of RRF? Where would a feature request like that need to be submitted?

It could be backwards compatible by simply introducing another parameter to M106, which specifies the range, like M106 X100:255 (I know X is already used, it's just intended as a placeholder).

I've got @Egon-Net's digital-to-analog board for use with a (non-PWM) part cooling fan with the Duet 3 mini 5+.

I finally found the time to hook it up, but am looking for a nicer way to the fan speed control. The thing is:
Egon's board makes 0-255 PWM turn into 0-12v. My fan only turns on at 4.5v. I configured the minimum speed to be 100 PWM (with M106 L100).

When turning the fan on and setting it's speed, I'm noticing the following:
1-40% = constant 4.7v
40-100% = 4.7 - 12v

I would however like it to behave like this:
1-100% = 4.7 - 12v (I.e. 100-255 PWM)

Is this (currently) possible in some way?

@egon-net no idea what that difference means (if someone can recommend me a good electronics course, please do ), but the following should be good then!?

CM-100N-X7R SR PASSIVES

@egon-net @dc42 thanks! I recon the following should do for a capacitor then? A ceramic one, as electrolytic doesn't even seem available at 100nF, does that matter? There was mention of ESR with use of an electrolytic capacitor / being used in the simulation?

SA105E104MARTB AVX

@egon-net thanks for making these graphs, very useful to me! Does the voltage still overshoot to about 16V with 100% PWM, when using a 100nF capacitor?

How about a capacitor somewhere between 100nF and 1µF? I.e. 0.47µF for instance, I figure that might be a nice middle ground for ripple with not too much of an overshoot ?

I've contacted @Egon-Net to score at least one of his boards when he makes the next batch

@dc42 thanks for confirming that again! I'd also like to try that 'simple way' with just the inductor and capacitor for myself. Although I can't find the specific inductor all that conveniently; are the following inductor and capacitor fit for the job? They are 1mH and 1µF, matching the given numbers, but I can't quite judge their other properties.

• RLB0914-102KL BOURNS
• UPS2D010MED NICHICON

Also:

• What if the PWM frequency isn't increased (which might for instance temporarily occur after a reset), does that create any serious issue or potential damage to the Duet?
• Is it normal for capacitors to have a rated lifetime of 2000h? Seems short?

Interesting, I didn't ran into @Egon-Net his post yet. Thanks for sharing it!

From what I gather in the thread, his board seems more complicated/expensive then necessary for my application, maybe; as indicated by this post: https://forum.duet3d.com/topic/21680/designing-a-pwm-to-analog-mini-board-for-fans/50?_=1620147998783

I'll send @Egon-Net a message regardless for sure

Hiya,

I'd like to connect 12V fans to my Duet 3 Mini 5+ that don’t allow/like PWM control, and feed them a constant voltage (0-12V) based on the PWM duty cycle.

I plan to make a little PCB which sits between the board and fans. Unfortunately I’m not taught in electronics, at all, designing circuits is unknown territory to me. I’ve found this (https://forum.duet3d.com/topic/6227/rc-low-pass-filter-for-blower-fan/9) topic by @wilriker, from which I understand he is trying/tried the same using a Duet 2(?).

His topic includes a schematic, and it seems all I might need is an inductor and capacitor to get this to work? I’m not so sure if the components & values in the schematic are any good for 12V / the Duet 3 Mini 5+ / with my fans

Hope someone can help me out!

PS: my fans have the following specs:

• 4.5~13.8V - 196mA (max)
• 4.5~13.8V - 100mA / max 115mA

Thanks, I gather hardware-wise things should be compatible?

The controller/display is implemented in Marlin, with that as some context I’m happy to give the software-side a shot. Although I don’t know the complexity of the matter, I’m not experienced with RRF’s codebase (or even C++). Can you give me an indication of the difficulty of this feature and/or pointers where to get started?

Hi,

I’m looking to rejuvenate an Ultimaker 2, starting by giving it some proper electronics.

I like to keep the front panel (the "UltiController", containing: SD card-reader, oled-screen and encoder) in place. Can this work together with the Duet 3 Mini 5+?

The display is 128x64, which is said to be compatible according the documentation, but I'm not sure about the controller & voltage levels. The schematic of the UltiController can be found here: https://github.com/Ultimaker/Ultimaker2/blob/master/1249_Ulticontroller_Board_(x1)/UltiController rev. 2.1.pdf