Add extra servo (LEGO or not) to BrickPi[SOLVED]


#1

Hi everyone,

As my first post, I’d like to express my excitement to start a new (and the first) project, with BrickPi.

I have some background with Mindstorms since long, but now I need something that allows me to do image processing and EV3 is not quite there. So, Let’s see what I can do with BrickPi. :slight_smile:

To the question now:

  • Is it possible and easy to attach an extra (5th) servo to the Raspberry Pi, using it’s remaining pins? How straight is it? Is it as easy as following any tutorial on Youtube on how to connect a servo to a RPi? If not, what are the suggestions?

Reducing to 4 motors is not an option. It doesn’t have to be LEGO (it would be better), since that seems an harder task. I would exclude buying extra multiplexers and/or using LEGO PF in any way. So, let’s focus on regular servo. It doesn’t even need to have continuous rotation.

I’m waiting to know this, before placing an order, because the 2-servo pack seems a good option to add.

Thanks for the support!


#2

Yes it is. First that two servo pack is fine however you need the pivotpi itself. If you get the brickpi you’ll notice that the pin extend. Meaning you can stack the pivotpi on top of the brickpi.
Just the pivotpi can be found here: https://www.dexterindustries.com/shop/pivotpi-board/
Or if you want servos to come with it that kit is also here: https://www.dexterindustries.com/shop/pivotpi-base-kit-servo-controller-for-raspberry-pi/

@JohnC nicely shows how to stack a hat on top of brickpi: Arduberry and BrickPi together?[SOLVED]


#3

Thanks graykevinb,

And is it safe to assume that the PivotPi does not use the same resources as the BrickPi? The UARTs I guess can be the problem.

This is good because I can use even more servos if needed. I was wondering if a simple servo has space using the remaining pins. Does anyone know that?

Hope someone could confirm this. :wink:


#4

It looks like PivotPi uses I2C, which seems to not use the same UART pins. However, I do see in the BrickPi interface schematic here:
https://github.com/DexterInd/BrickPi/blob/master/Hardware%20Design/BrickPi_2_8_1.pdf

that the pins for I2C, SDA and SCL, pin 3 and 5, are connected to a ‘Power Supply’ component on upper left side. So… I’m a bit afraid it won’t actually work.


#5

I invited @cleoqc. He knows about these sorta things.


#6

@ricardocrl,
The I2C on the BrickPi is connected to a chip which measures the power supply. However, the way I2C works is that it allows you to connect upto 127 devices on the same 2 I2C pins and can address each of them individiually. So, there should not be any problem when you use the PivotPi with the BrickPi.

We have a couple of other products like the line follower and the GrovePi which work using the same principle.


#7

Great! I have ordered the BrickPi + Pivot base kit. Let’s see what comes out of it. :slight_smile:

Thanks a lot for the help!