Baby-O at 3.7V?

Hi, I was just wondering if you make a Baby-O that works on 3.7VDC? Is it possible to run the current Baby-O at 3.7 somehow? The reason is that I’d like to use a li-poly battery with it and my motors aren’t rated from 7.4V if I go with two batteries.


Hello Denis,

We don’t make a Baby-O that runs at 3.7 V. At least one person has had success modifying their Baby Orangutan to run at 3.7 V. Here is a forum thread about it:

Here is a summary: you have to change the AVR to use its internal 8 MHz clock instead of the 20 MHz external oscillator. You will also need to lower the brownout detection voltage from 4.3 V to 2.7 V or disable it. You can choose to power the BabyO through Vcc directly, bypassing the voltage regulator.

Please note that certain functions in the Pololu AVR library depend on the AVR running at 20 MHz. So be careful about which library functions you use.

- Ryan

Hi, I had put this project on hold for a bit. I am now returning to it. I’ve read the posts at the link you sent. I understand about changing the clock to <10Mhz. I know how to do that.

My question is where do I connect the voltage to to make the whole thing run? I can put it to the Vcc which bypasses the voltage regulator, but I notice that the “bat” for the motor is on the left of the regulator. So do I also connect the voltage there too? Will jumpering the regulator’s in and out damage anything or cause any ill effects?



You definitely need to put your 3.7V on the VIN side since that is the motor supply node. After that, you can short across the regulator if you want, though it won’t make much difference. You’ll probably lose a few tenths of a volt in the regulator, so you’d avoid that. The regulator might draw an extra milliamp, which probably won’t be noticeable, but if you care, you could remove the regulator, in which case you’d definitely need to connect to Vcc and VIN to your battery.

- Jan

Why do you say that it won’t make much of a difference? The regulator regulates to 5V right? so if you put less than 5V in, will it just pass it through to the other side and not try to regulate it?

The regulator is a linear regulator that only regulates voltage downward. If you pass in 15 V, you get 5 V out. If you pass in 3V, you get a little less than 3V out. For more information about the relationship between the input and output voltage, check out the datasheet for the regulator.


Ok, that makes sense. I will try it.

Thanks for your help.