Contol of two DC motors with Baby Orangutan

Hi all,

for some time I’m developing a mobile device for which I would like to use the Pololu Baby Orangutang B-328 Robot Controller. I would like to power and control two small DC motors with it. I would like to make sure that I have all the parts I need from Pololu before I let it ship to The Netherlands, Europe. I’ve been doing a little research myself and I’ve selected the next components:

Wall Power Adapter: 5VDC, 5A, 5.5×2.1mm Barrel Jack, Center-Positive (pololu.com/product/1462)
DC Power Adapter Barrel Jack (pololu.com/product/1139)
Pololu Adjustable 9-30V Step-Up/Step-Down Voltage Regulator S18V20AHV (pololu.com/product/2573)
Baby Orangutan B-328 Robot Controller (pololu.com/product/1220)
99:1 Metal Gearmotor 25Dx54L mm (pololu.com/product/1587)
35:1 Metal Gearmotor 15.5Dx30L mm (pololu.com/product/1597)

350-Piece Jumper Wire Kit without Case (pololu.com/product/347)
400-Point Breadboard (pololu.com/product/351)
0.100" (2.54 mm) Breakaway Male Header: 1x40-Pin, Straight (pololu.com/product/965)
Pololu USB AVR Programmer (pololu.com/product/1300)

I’m a mechanical engineer so this is something new for me. I would appreciate it if someone can help me with this. My question is, did I select the right components to build a system where I can power and individually control the two DC motors?
The components will be used in a mobile device so it will be powered by a lithium-ion battery.

Thanks in advance.

Greeting,
Wilfred.

Hello, Wilfred.

The Baby Orangutan might work for those motors, but the current draw of the 99:1 metal gearmotor 25Dx54L mm would be pushing the limits of the motor driver on the Baby Orangutan. You might consider using a more powerful motor driver that can deliver more current. Also, that regulator might have issues supplying enough current for your motors when stepping up from 5V to something higher. If you tell me more about what you are trying to do, I might be able to make a more specific suggestions.

- Grant

Thanks Grant for your reply. I can’t tell you what kind of a device it is since it doesn’t exist in this form. I first have to build a prototype with components I select. I don’t have any calculations whatsoever. So my first choice will be based on specifications. Building the prototype will tell if I made the right choices.

I made a sketch of what I would like to build:

I haven’t made a choice yet of which voltage I will use. 9V, 12V or 24V. 24V will be my last choice. About the regulator, the Pololu Step-Down Voltage Regulator D15V70F5S3 would be a better choice I think when I use two more powerful DC motors.
At first I would like to make sure that the components will work flawlessly in a system. So no, to an extent, limitations in Voltage or current.

I am aware of the limited information I can give you. But I hope that you can help me based on the information I gave you.

From your diagram, it looks like you are planning to drive both motors from the Baby Orangutan. As I stated in my previous post, the current draw of the 99:1 metal gearmotor 25Dx54L mm would be pushing the limits of the motor driver on the Baby Orangutan. I recommend using a more powerful motor driver that can deliver more current.

As for the regulator, I am a little confused about how you are supplying power. In your first post, it seemed like you were planning on stepping the voltage up. However, from your new post, it sounds like you are stepping the voltage down. It is hard for me to give a recommendation on a regulator without knowing what voltages you plan to use for the input and output.

-Grant

Okay. Let’s forget about the components I selected. The diagram schematically shows how the components are going to be connected.
I will use a 12V battery as a power supply.
Motor 1 (DC1):
Input voltage: 5 - 13V
Current: 4.5A
This is not a Pololu item. It is a high pressure liquid pump powered by a DC motor.
Motor 2 (DC2):
Input voltage: 5
Current: 2.2A
(see pololu.com/product/1587/specs or similar)

I’m going to use motor 1 for sure. Motor 2 can change depending on the possibilities which Pololu has.

Based on these numbers, the baby orangutan might be pushed to it’s limits. Would it be possible for you to give me a recommendation for a regulator and a motor controller?

Thank you in advance.

As I said in my previous post, it is hard for me to give a recommendation on a regulator without knowing your exact output voltage. For the motor driver, we generally recommend selecting one that has a continuous current rating greater than the stall current of your motor. You can find a list of all our motor drivers and controllers here; it is up to you to determine which one is most appropriate for your application.

- Grant