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martin-bienz

UMO 1.5.7 PCB, LED / 19V DC output - PWM? ON / OFF?

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Hi Guys,

I was really looking for this and I could not find a concrete anwser, so question for you UMO owners out there :).

The specifications of the 1.5.7 board I could find here: http://reprap.org/wiki/Ultimaker's_v1.5.7_PCB describe the specifications and include this feature:

- A PWM output with power for LED arrays and other lighting

Now, I allways assumed this is the port labeld LED Port / 19DVC on 1.5.7, would make sense right? Picture of the output on my board that I connected my LEDs to, just to be sure we are talking about the same thing / output:

5a33161de1511_1.5.7LEDs.thumb.JPG.6fb738a1668c0ddfeb2fa7f6a5bc7dd0.JPG

It works, they seem to be default ON / max PWM.

Someone knows if this is actually PWMable and / or controllable with GCODE?

Thanks

Martin

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Unfortunately, as near as I can remember, that WIKI is incorrect. I don't believe the LED connector can be PWM'ed. I believe it is hardwired to 19V.

You'll need EagleCAD to open the files but they are here:

https://github.com/Ultimaker/UltimakerOriginal/tree/master/1090_Arduino_Mega_Ultimaker_Shield_1.5.7

If my memory is correct, you might be able to run the LEDs off the second heater output if you don't have a dual extruder output. But you would need LEDs that can run on 19V. And you might need to tweak the firmware.

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@anon4321, thank you very much! That would confirm my fears :). I will look at the eagle files tomorrow. Maybe I will then go for exp3, pin13 and an additional transistor (my leds run at 19v, no problem) to turn them on and off (pwm). I will let you know if you are interested.

I would definitely be interested! I have my UMO (heated bed in the mail (I hope)) illuminated by 3 IKEA Dioder LED strips. They are on a completely separate power supply since I don't know enough about electronics to use options on the board. Solid advice on hooking them up to the board would be highly appreciated - pwm is secondary. Thanks.

Edited by Guest

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Ahhh... no eagle installed. okay. I just assume it's a fixed 19V DV source and use P13, EXP3 to create a small pwm circuit with an npn transiistor. my leds, 3 x dioder, I seem to remember are in series 18V which is just fine. They draw around 0.4 Amps (400 mA) so with a standard npn BC337 or so, this should be doable. I guess... will try.

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okay. I have it running. I have no clue why, but P13 did not do anything ... at all. So I took P12, that is doing ON 5V and OFF just fine. So with P12, I can now switch a BC337 on that switches the 19 V DC output on and voila, the LEDs light up.

That means, I can now turn on via M42 P12 S255 and turn OFF by sending M42 P12 S0. Works just fine.

Maybe the BC337 is a bit on the lower end, could be higher? The LEDs draw only .45 A and my datasheet tells me that my BC337 is good up to 0.8 Ic... it gets warm, hot. let's see how it goes.

More info upon request.

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I installed Eagle and checked. The LEDs output is just the 19V supply. There is nothing controlling it.

If I were you, I would just duplicate the fan controller portion of the shield. It's a BD679 darlington pair with a 1k current limiting resistor for the base. Good for a couple amps.

Buy a couple extra BD679 in as backups for the one on the shield. Then you have a spare should the fan been shorted.

The marlin firmware seems to define a LED control pin as pin 13. If you figure out what pin that maps to on the shield and use it for the LED drive then I think you will get GCODE control of the LEDs without changing the firmware. Although I'm making a lot of assumptions.

See line 1319 here https://github.com/Ultimaker/Marlin/blob/Marlin_v1/Marlin/pins.h

This is the fan control portion of the shield:

5a33162859d86_Screenshot(1).thumb.png.cd314c84aecc48d1ea600c45c6f61041.png

Looks like pin 13 is in the group near heated bed output

Good luck.

5a33162859d86_Screenshot(1).thumb.png.cd314c84aecc48d1ea600c45c6f61041.png

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@anon4321, thank you!

hmm... I don't think the PWM frequency is too high, I think (am not sure) I used those transistors before to drive som LEDs for another arduino project. But hey, I will try with BD679 if I get some. For now, on and off is just fine on PIN12. I will need to look at the schematics again...

@Dim3nsioneer, great thanks, but is the UM2 Go not equiped with a "new" board? I thought they allready have a powered PWM output for LEDs? Or did @gr5 do seomthing custom with the analaog PINS?

I have also created my own PWM board for the heated bed, works quite well. I will need to look at it once I have some more time...

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short update... it works just fine as described on PIN12 (without PWM). I had it on for more than 24 h and the BC337 transistor is still working :). I put the small board just under one of my electornics cooling fans, so I guess it's fine.

Still wondering why my P13 is dead...

Next step is probably connecting a small dc/dc voltage regulator to the print cooling fan output (19V to 12V) in order to be able to install super silent and efficient 12 V (or maybe even 2 small 5 V) fans in paralel... for better print cooling. UMO hacking is still cool.

Edited by Guest
small corrections, typos

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