Full schematics for 3pi

Support Robots
1

Hi,

I’ve seen schematics for the 3pi, and links to “full schematics”, but i’ve not found anything that expands on the push button power on circuits and the vboost generator.

Are these parts of the 3pi public?

Cheers,
Chris

2

Hello.

We are not making those parts of the circuit public, but the switch design is public in the sense that it is patented. Please note that we sell the boost regulator and power circuit as individual products:

pololu.com/catalog/product/751
pololu.com/catalog/product/791

Are you curious for your own understanding or personal use, or are you interested in building these features into a product?

- Jan

3

Hi Jan,

I already have a 3pi that I am planning on making even more awesome than it already is (i know… tall order), and to do this I was hoping to be able to take control or replicate the push button power control from external software. I was hoping that I can replace or parallel the pushbutton with a FET. The schematics would have helped confirm or otherwise if that was going to be possible.

The vboost circuit is really neat… I’ll just go buy a few for now. My guess is that it is based on an standard SMPS parts from someone like Linear, and that your implementation is more or less the reference design, but just being able to jam it into a breadboard is so useful.

Thanks,
Chris

4

Doing the same thing the switch does with a FET is unlikely to be simple. However, if you already have some external circuit that is always powered, driving a P-channel MOSFET from that to separately turn power on and off would be much easier.

- Jan

5

Thanks!

So I was hoping to be a be able to control the 3pi on/off, from the external circuit, and also control the power in to the charge pins. Idea being that, when the batteries get low, switch off the 3pi so ti isn not loading the batteries, and then fast charging them.

Thanks,
Chris

6

Is all that necessary? If your second power source is mobile, using it to charge a different pack is quite inefficient and probably unnecessary; if you have some charging station, can’t you just turn off the LEDs and motors and leave the rest of the robot on while charging?

- Jan