Power Pi and Motors


Very much a pi noob, and more so to physical computing/electronics. I am investigating options to create something similar to the pi-lapse rail feature on this website; http://www.davidhunt.ie/motorised-time-lapse-rail-with-raspberry-pi/3/

What i am wondering if whether the PicoBorg Reverse can provide power to both the Pi and motors from a single battery pack using the GPIO connections? It appears that it may do this however I wanted to check, i assume the PicoBorg Reverse has a dc/dc regulator and therefore could power the pi at the same time?

If I get a similar motor of around 12v similar to that in the link would 8xAA batteries power the motor and a Pi model b+, i guess i also need to check the power capabilities of the motor to move the camera rig.

Any advise on the electronics side you can provide would be greatly appreciated. Thank you.

piborg's picture

The PicoBorg Reverse does not have a DC/DC fitted, so it does not supply the 5v for running the Raspberry Pi.

What we do have is another board called BattBorg, which does provide the 5v to the Raspberry Pi.
The BattBorg also fits neatly onto the PicoBorg Reverse to make a single attachment:

You would need to connect the batteries to both the PicoBorg Reverse and the BattBorg to make this work, but they can share the same battery pack (See our DiddyBorg build instructions for an example here, towards the bottom).

As a general rule of thumb it is not a bad idea to have motors which are a slightly lower voltage than the power supply.
For example 9v motors with a 12v battery pack would work well.
You can set the output voltage to the motors using the provided PicoBorg Reverse software.


Thanks for your great help, i am slightly confused how the DiddyBorg power works, it appears unless i am mistaken that you end up with a 9v power cable from both the PicoBorg Reverse and the Battborg? There is a picture showing the Battborg with a 9v power connection and the followed by a picture showing a second 9v power connect to the centre pins on the PicoBorg Reverse? Is there a simple diagram covering the wiring of the DiddyBorg?


I can appreciate your confusion, it took me a short bit to sort out how exactly to hook all of this up as well. However, once I got it, I realized it actually is quite simple.

The key is the fact that the PicoBorg Reverse has the ability to drive the motors with a separate power supply. Therefore, if you have motors that require more power than the Raspberry Pi can handle, they would effectively be on a separate circuit. That power source goes through the middle screw terminals on the Reverse.

In the case of the DiddyBorg, a single battery pack is sufficient for both the motor drive and the Raspberry Pi. So a single 9v power connector is being connected to both the BattBorg and the PicoBorg Reverse in series, which is then plugged into the one battery pack.

Guys, I have a question I'd like to put up for some consideration..... just to get some more opinions on the situation. I apologize if it seems like I'm hijacking this thread, but it does match this overall topic very well.

With my current bot project, I am using 2 8x AA battery packs; one is going to the BattBorg and one to the PicoBorg Reverse. I've been wanting to put a switch in the line so I don't have to disconnect them to turn it off; rather than having two switches I'd prefer to have one though. What is the ideal way to turn this into one circuit without undue drain on the batteries?

The current charge going to the motors is sufficient for the time being (that may change if/when I rebuild the gear boxes and swap out the motors) so I don't really want to put the two battery packs in series and increase the voltage. Perhaps aligning the two separate packs in parallel with each other and connecting them to the two boards in series?

--Cody E.

piborg's picture

The simplest thing to do would be to get a double pole, single throw (DPST) switch.

The idea is that it has one physical switch button, but behaves like two separate switches internally.
It should be electrically equivalent to using two switches.

Each switch should have four pins, here is an example from Ebay:

Right, and that's simple enough to do.... certainly one of the options I've considered (though neglected to mention.) However, I am somewhat curious what you think of the idea of putting the two packs in parallel?

This is the chassis of the guy I've been building: http://youtu.be/1O1GPlPJWG0

I'm ultimately looking for the ideal setup between a host of concerns:

  • Enough voltage to the motors to allow it to run on any common flooring surface
  • Low enough voltage to keep gear noise to an acceptable minimum (<=10V)
  • Prolonged battery life to Raspberry Pi
  • Simple recharging process
  • Power cost

I have a handful of NiCad packs from various RC cars ranging from 5-9V; I considered using one or more of those due to their lifespan and ease to charge. However, I don't want to design around something that is more expensive to replace when it finally does wear out. I also have a wonderful little power box that holds 4 18650 LiIon cells; that is great because I have a TON of those from salvaged laptop power packs. However, it is set up to output through USB, so 5V and roughly 1A. Alone it might be sufficient for the RPi, but it would defeat the purpose of having the BattBorg, and doesn't last quite as long it seems.

Ideally I would love to be able to design something with which I can switch it to "Charge" and plug a barrel jack right into the chassis and have it recharge without having to pull the batteries out. That would be a piece of cake with NiCad or LiIon; I've never attempted anything of the sort with rechargeable AA (aren't they NiMH?)

--Cody E.

piborg's picture

Putting both packs in parallel should be fine, just make sure that you do not connect one charged and one discharged.

Having a switch to connect the batteries for charging instead is possible, but you would need a charging circuit.
Rechargeable AAs are typically NiMH, which has a very similar charging circuit to NiCad.
I am not sure if the AAs can be charged in place, all of the chargers we use connect to every battery separately.

We do have an older robot we assembled which used two RC NiCads which worked rather well.
The big advantage to that is we just used the standard wall charger by unplugging the batteries, but not removing them from the robot.

As part of their Cyber Monday yesterday, Sparkfun.com had one of their LiPoly charger/booster boards 50% off. So I ordered that and a 2000mAh pack. I also have a small 3v solar panel that I've never used, but which can be added to the charger board. The voltage from the LiPo pack is of course quite a bit less than the other battery packs that I have on the bot right now, but I am anxious to start playing around with it to see how I can work it in conjunction with the BattBorg!


I have bought a Diddy Borg on 08/2016 and I have not mounted it until today.

My pi is configured correctly and works fine, but when I install it on the
Diddy Borg, it seems that the PicoBorg Reverse don't feed it with the 5V trough the pins (I have
measured it with a voltimeter). I have tested and there is 5V on the picoBorg Reverse inputs and
in the BattBorg.

Is a possible malfunction on the PicoBorg Reverse?

Thank you
(My order is 21387)

piborg's picture

If the BattBorg is supplying 5V then the most likely cause is that the 3-pin cable is not making a good connection. One of the cables carries the power (5V and GND), the other carries the logic signals (3V3 and I2C).

The first thing to do is check that the 3-pin cables are connected correctly. I would suggest double-checking the DiddyBorg build instructions match how you have the cable connected.

The DiddyBorg kit usually comes with a spare 3-pin cable. If the cables are connected correctly, I would try swapping the cable which has the 5V power to see if it fixes the issue.

This is the cable which has 5V on it:

Hello again,

I have measured on the pins of the picoborg reverse that will feed the pi (without the cable) and have 0 V.

I don´t know if the BattBorg is supllying 5V, I only know that it have 5V on his entries.

thank you

piborg's picture

I think there may be some confusion here. The BattBorg is designed to take a higher voltage in and generates 5V from it. It needs at least 7V to work correctly, ideally 7.5V or more.

What battery / power supply to you have connected to the DiddyBorg at the moment?

I think you are right, I have used a power supply of 5V alone. I will try with 7.5 V, and I will say you something.


I have used a 12V power supply, and the DiddyBorg works perfectly.

thank you very much

piborg's picture

Great news, it is always nice to hear when problems get fixed :D

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