Pulling power from mini Rambo?

I’ve got this thing I want to incorporate into my MP3DP build but would like to pull power off the board so it activates when the printer is powered up. The thing right now is run off two AA batteries that are connected in series to give 3v. I’m digging to see what the max voltage it can handle is and will report back here when I figure that out but in the meantime does anyone know how to explain to me where I can pull power from? I have the power supply from Amazon (from the Shop link).

No you have 12v, or a limited amount of 5v. I don’t think you can get 3. Some sort of mosfet or relay to switch it would be another way.

There’s not a lot of info in the way of specs on their website so I emailed them. They do have a whole pile of 12v options so I think I might be ok here. I assume of the thing runs on 2 AAs right now there’s little risk of me drawing too much power through the miniRambo right? Would hate to burn it up.

I don’t think you can get 3V from the board. But you might be able to get it from different power supplies. I am using an old power supply from another old device that outputs 12v, 5v and 3v.

Batteries can supply a lot of current. Do the batteries last long? That would be a good way to determine the current usage if they won’t specify it (unless you can measure it with a meter).

There are quite a few ways to power something from a different voltage, but it depends on the amount of current you need. An voltage regulator like this would be a good way to step down the voltage, but it wastes power (in the form of heat) so it would only be for low-ish current devices:

As an aside, the fact that you haven’t said what it is makes me super curious :).

Also, there is a bit of spare 5V current, although I don’t lnow where it mihht be spec’ed. Doesn’t the (+) on the endstop connectors have 5V.

Hahahah…and if I say much more in response to your questions I might give it away…maybe I’ll stick with a standalone power supply so I can let the cat out of the bag and then once you all know what’s been brewed up here I can fess up and get help making it better…

So the word on the street is that it’s gotta be 3v but I could buy a 12v version - which I’ll consider doing after we’re all up and running and you’ve all seen the build finished. I don’t need to spend more $$ on just bells and whistles. Not right now anyway. I do have a project lined up that if I can figure out the MP3DP I should be able to get it to start paying for itself sooner rather than later. Tough problem to have, I know. I’m lucky…that’s for damn sure. I think I was just a the right place at the right time talking to the right person (about why I was late to get to our meeting…I was cutting the MP3DP pieces ; )

A 12V version would be very easy to use, and keep your mini rambo out of danger.

You could also do something like this, to get 3V from the 12V supply:

There are a lot of designs like this, just make sure it’s rated much more than the current you need.

I’m not going to be able to sleep until you tell me what this is though. Please let us know as soon as you can :slight_smile: . My best guess right now: 3D doodle pen? No, pancake batter extruder? No, tatoo machine?