Steal some power from the PSU  

Re: Steal some power from the PSU

For the pi you will need a 12v to 5v buck converter. I have used both of these with great success...

https://www.amazon.com/GEREE-Converter-Module-Output-Adapter/dp/B00O6RJLQC/ref=sr_1_1?ie=UTF8&qid=1483971325&sr=8-1&keywords=12v%2Bto%2B5v%2Bmicro%2Busb&th=1

https://www.amazon.com/GEREE-Converter-Module-Output-Adapter/dp/B00O6R9PCC/ref=sr_1_1?ie=UTF8&qid=1483971325&sr=8-1&keywords=12v%2Bto%2B5v%2Bmicro%2Busb&th=1

For the LED's, if they are 12v, you can wire them straight into the spare 12v output of the power supply.

Re: Steal some power from the PSU

Cool, thanks richard, this is exactly what i was looking for. So the converter is also wired into the spare 12v terminals on the psu? I actually didn't notice any extra terminals when I was installing the psu, I will have to take a deeper look.

Thanks again!

Re: Steal some power from the PSU

I think they are hidden behind the cover, you may have to drill holes in it. Saw a picture with a guy who did just that for an additional fan.

Re: Steal some power from the PSU

Here is a pic of the PSU inside... you can see a V+/V- spare (12v). You'll have to make the wires hole a bit larger.

Re: Steal some power from the PSU

Here is a pic of the PSU inside... you can see a V+/V- spare (12v). You'll have to make the wires hole a bit larger.
IMG_20161209_204027.jpg

Thank you so much @patrizio.b ! That is so helpful. So maybe it might make sense to add some standard 12v terminals to the case for cleanliness and/or quick (dis)connect. Maybe like an APM or MOLEX port?

Re: Steal some power from the PSU

Well I was thinking of making the plastic PSU cover 1-2cm deeper, add the buck converter at the bottom, add a Molex on the back (in order to have both +12 and +5) and a second button on the side (to enable and disable such molex connector). That would do for led and pi.
Too bad i don't have time 😥

But, if you're willing to, please do it with openSCAD, and start from the SCAD file of this thing, which has the power socket on the back, very neat:
http://www.thingiverse.com/thing:1942906

Re: Steal some power from the PSU

You got it. Looks like my next project.

Re: Steal some power from the PSU

Well I was thinking of making the plastic PSU cover 1-2cm deeper, add the buck converter at the bottom, add a Molex on the back (in order to have both +12 and +5) and a second button on the side (to enable and disable such molex connector). That would do for led and pi.
Too bad i don't have time 😥

But, if you're willing to, please do it with openSCAD, and start from the SCAD file of this thing, which has the power socket on the back, very neat:
http://www.thingiverse.com/thing:1942906

So should I be designing around something like

https://www.amazon.com/Molex-2-Pin-Connector-Kit-0-093/dp/B004GUQ2ZM/ref=sr_1_3?ie=UTF8&qid=1484693790&sr=8-3&keywords=molex+connectors
?

Re: Steal some power from the PSU

Why not the 4 pin ones, like those found on personal computers and ATX PSUs? They are more common, and you could put there +5v, +12v and GND. I mean these (but panel mount type):

Re: Steal some power from the PSU

I guess I was looking at 2 pin because only 2 will be needed... i wasn't planning on wiring 5v up to the molex as nobody really needs 5vs outside of a usb context.

But I hear you on what is most common. The 2 pin is physically smaller, that is pretty nice considering the limited space we are working with.

Re: Steal some power from the PSU

You could power the raspberry (octoprint) from the +5v. Indeed the 2pin version is neat and would fit better. Difficult decision 😛

...well, rethinking about it, maybe an USB connector is better suited for 5v after all.

Re: Steal some power from the PSU

As long as you do not exceed the power in, you will be OK. However a margin I have always used is a 50% over specification in power supplies. Just my 40 years of experience, In Heavy and light current projects.

Re: Steal some power from the PSU

I've measured power at the wall, and even printing ABS at almost 200% its usually around 150-180W max. The 12V supply is rated at 20A (240W), so there's plenty of headroom to power a RPi. I used one of those LM2596 buck converters that sell for a couple dollars on ebay, soldered the end of a USB cable onto it and set to 5V and it works just fine.

Re: Steal some power from the PSU

This is a reading of a power strip that the printer (while printing), the octopi, and a 100 "watt" florescent light are using.

The plan is to power the octopi with the buck, which is wired to the extra 12 volt terminals. Along with some 12 volt LED lights (light strip). The lights will go around the frame, and around the camera. There will be two fuses, one for the buck and one for the LEDs. I need to do some math to make sure I get the right ones. Most importantly is to not overload the PSU.

I am hoping to use molex connectors for all of it.

Re: Steal some power from the PSU

Here is a pic of the PSU inside... you can see a V+/V- spare (12v). You'll have to make the wires hole a bit larger.
IMG_20161209_204027.jpg
Patrizio, can you confirm those are 10 gauge wires? They look it from the picture. Hoping you know so I don't have to crack open my PSU cover right now.

Re: Steal some power from the PSU

One standard 12V connector in amateur radio and some making circles is the Anderson Powerpole connector http://www.andersonpower.com/us/en/products/powerpole/ . I did not bother to print a new shell for the power pack connector end, I simply cut a rectangular hole in the existing one that's a tight fit for a pair of Powerpoles, connected them to the unused terminals with3A twin flex, and glued them in place with epoxy. Works well and has given me no trouble so far.

I'm building a wood and acrylic case and need about 3-4 watts for some lighting and a small fan for fume extraction. I'll post plans and pictures when it's done.

Re: Steal some power from the PSU

https://www.thingiverse.com/thing:2264196

Re: Steal some power from the PSU

Here is the best thing I've found to provide USB power to the Pi:

https://www.thingiverse.com/thing:2264196

I have it setup and it works...it's just a bitch to get the wires routed with the USB thing in there...but it's doable.

Re: Steal some power from the PSU

Probably a little late for some of you, but if you're using a PiZero, RPi2, or (probably underclocked) RPi3, you can easily grab power for the RPi from one of the unused max endstop connectors on the RAMBo Mini:

I've been using mine, with USB WiFi module for a year now without issues.

I use this case to mount the RPi right over the RAMBo Mini case: https://www.thingiverse.com/thing:1668505

Then snake the RPi camera with a long ribbon extension out the bottom, through the RAMBo Mini case, under the frame to my camera mount and it works great - very clean: https://www.thingiverse.com/thing:2333969

BTW- Glad to see people getting some good use out of my rear-exit PS cover design 🙂

I have the MK3 on pre-order so will be doing the same for it once the scad files go up.

-=dave