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tachyio

Adding 12V LEDs to Ultimaker

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I have a string of 12V white LEDs that I want to add to the ultimaker, so I can see prints better. Know anywhere where I can connect them to, that supplies 12V?

There isn't much spare 12V supply in the UM, you can draw some extra current from the port that runs the stepper fan, but the LM7812 that is providing the 12V for the fan will get hot, and needs a cooling fin, or other cooling means, plus it can not support infinite amounts of current (I think they are rated 1A, but drawing 12V 1A means that 7W heat are generated, enough to kill that little thing without cooling).

I made a custom board, with 2 additional LM7812, getting 19V from the heated bed terminal, and GND where ever it's convenient for you:

_MG_2277%252012V%2520supply.jpg

_MG_2278%252012V%2520supply.jpg

but they are still getting warm... the average 12V LED strip draws about 200mAh, so connecting about 3 to each LM7812 is well within bounds, 4 is probably still OK, depending on the size of your cooling fin.

For another project I am using proper voltage controllers: http://www.pololu.com/catalog/product/2110 and should have used that one instead of the two LM7812, but now I am too lazy to fix it, since it works.

as another simple alternative, you can power 12V LED strips (and additional fans) from and external power supply, I have for example an old apple iPod firewire charger (first gen iPod!) that will happily supply 12V, and FW400 cables are abundant (simply chop of one end, and wire the 2 power supply cables accordingly, ignoring the 4 data wires.

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Hmm I connected quite a long LED strip, removing now for fear of overheat. The light wasn't constant too and appeared to pulse in sync with the 12V fan current - I'm assuming the fan motor is pulsed to save energy, seems that way.

More importantly, you mentioned there's a 19V terminal for a heated bed? I want to try printing in ABS as what little that I've printed looks awesomely smooth! Anyway for me to connect a HBP?

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More importantly, you mentioned there's a 19V terminal for a heated bed? I want to try printing in ABS as what little that I've printed looks awesomely smooth! Anyway for me to connect a HBP?

Yes, there is 19V in many places, that is the juice that is coming from the power supply. the stock power supply has 120W iirc, which isn't enough to run a HBP (which needs 80-200W, depending on what kind you like, just by itself, and hooking it up to your stock power supply will not end well). see HBP discussions on the google group, and elsewhere in this forum.

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I'm not really good with electronics (Still on the "Don't let the smoke out" theory, ha) but I am wanting to do this.

Will I need any capacitors to run this to avoid "noise" or is it fine without since the input is DC? I am only trying to run one set of LED's from the spot on the board labeled 19VDC LED. It is the "Dioder" set from IKEA of flexible RGB lights I had lying around. Transformer from the wall outlet says it's output is 12VDC 5W max. I already have them in place and they look great, only eyesore is taking up 2 outlets.

I'm honestly not even sure how to use a breadboard. Could you please provide like a diagram or something of the sort of what you did up there? Do I need multiple regulators? Easily upgradeable to add fans like you have in the future?

Sorry to ask a million questions, any help appreciated.

-Mike

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You can run LEDs off of any voltage you want. If your LEDs already have a current limiting resistor (they probably do if they are labeled as 12V LEDs) then you will just need to add an additional resistor in series with the LED to adjust the current limit for the higher (19V) power supply voltage. Regular LEDs consume VERY little current compared to everything else in your printer (~20mA). If I make some assumptions about your LED I would guess that it has around a 560 ohm resistor in series already (20mA maximum current, 12V, 2.0V forward LED voltage). To safely run off of 19V you can just add another 560 ohm resistor. However, that will keep the current through the LED roughly the same, if it's too bright or you don't mind it being a little less bright you can always run it with a 1k resistor without any issues.

-Matt

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You can run LEDs off of any voltage you want. If your LEDs already have a current limiting resistor (they probably do if they are labeled as 12V LEDs) then you will just need to add an additional resistor in series with the LED to adjust the current limit for the higher (19V) power supply voltage. Regular LEDs consume VERY little current compared to everything else in your printer (~20mA). If I make some assumptions about your LED I would guess that it has around a 560 ohm resistor in series already (20mA maximum current, 12V, 2.0V forward LED voltage). To safely run off of 19V you can just add another 560 ohm resistor. However, that will keep the current through the LED roughly the same, if it's too bright or you don't mind it being a little less bright you can always run it with a 1k resistor without any issues.

please keep in mind that we were (probably) talking about LED strips, which use up a much greater current than a single LED...

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You inspired me to add my own lights.

I found these super bright diodes at Clas Ohlson. 5000 mcd, 3.2V 20mA

4 of them and a small resistor only draws 20mA from the 19V and I have 20000 mcd of light :-)

And of course I needed to add a light-switch 8-)

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You inspired me to add my own lights.

I found these super bright diodes at Clas Ohlson. 5000 mcd, 3.2V 20mA

4 of them and a small resistor only draws 20mA from the 19V and I have 20000 mcd of light :-)

And of course I needed to add a light-switch 8-)

That's a pretty nice setup you have going there!

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Does the size of the Elco's matter Kit? From what I understand it would only take longer to 'fill up'. So taking a 1000uF in stead of a 10uF? Or will that introduce stability issues? Isn't the 19V already stable and filtered?

I can't seem to find smaller caps here at home. I do have the 0.1uF though. I also seem to find enough diagrams where they just hook up the 0.1uF's without the elco's.

 

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So, I made my 7812 board to take 19V from the LEDs pins and convert it to 12V to power the IKEA Dioder leds.

It works!

http://i.imgur.com/5IaEPrW.jpg

http://i.imgur.com/Utkj96h.jpg

It uses 0.22A @ 12V. The heat sink looks kinda overkill, but the 7V difference times 0.22A is still roughly 1.5W and it got pretty hot. Better safe than sorry.

It works with a manual switch to turn the leds on and off, but is hackable to use Gcode if need be later on.

 

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