New HP motors for 3pi

Hi, it’s been a lot from I purchased the robot and still have no time to dedicate :frowning:
But now christmas are aproachig and some free time will come, and so will the upgrades to the 3pi :slight_smile:

My question: Will the new HP micro-motor work for the 3pi robot? I max consumes 1,6A at stall so I think the driver is capable enought, but want to certify. Will the programs work as normal, if I change the motors, or I’ve to reprogram all code relative to motor control?


We do not recommend using the HP motors on the 3pi. Have you used it with the stock motors yet? It’s already fast enough that it can be difficult to catch, and it could destroy itself if it slammed into a wall at full speed with the HP motors. Also, it’s not just the motor driver that has to handle the current: even with each motor drawing just 1A, that would be approximately 4A needed out of the batteries, and the whole power system (power switch, boost regulator) is not capable of delivering it.

If you really, really want to do it, it’s possible by reducing the boost voltage (which then counteracts the goal of increasing the top speed). Since the boost voltage impacts the reflectance sensor LED brightness, the corresponding resistor also needs to get changed. We have a few units we’ve modified here, and we got about a 15% increase in speed on our standard line course with 6" radius turns. That speed increase was without giving the motors full power because the robot would lose the line at faster speeds. One robot’s gearbox and motor driver got destroyed when the robot ran into something.

So, I don’t think it’s worth it since it’s a lot of work for a slight increase in performance and a bigger risk of destroying the robot. If you spend some time with the 3pi and still think it’s not fast enough, I can let you know which resistors to change.

- Jan

Ok, I will not try it, as you recommend.

I will try another way (new robot). So, baby orangutan will be capable to drive 2 micro-motors (HP version) continuosly without serioulsly getting too hot?

Hi dragonet80

The Baby Orangutan website description says that it can do about 1 A continuous. Some of our HP motors have stall currents above 1 A. As long as you use a motor with a lower than 1 amp stall current, and your power supply can handle the draw you should be okay.



The motor drivers used on the Baby Orangutan B are the same as those on the 3pi. As long as you keep operating voltage low (say around 5 or 6 V), you should be able to drive the HP versions of the micro metal gearmotors without too much risk. However, if the HP motors are held stalled for an extended period of time, the driver will overheat. Its thermal shutdown should protect the driver in such instances, but relying on thermal shutdown to avoid damage is not a good strategy.

In short, the HP motors have free-run currents that are well within the range of what the Baby Orangutan can handle and stall currents that, at 5 V, are a bit above what the Baby Orangutan can continuously output (but are within its peak abilities). If you take care not to stall the motors for long stretches or constantly switch direction (e.g. alternate rapidly between full forward and full reverse), the Baby Orangutan should be okay, but be aware that such an application has the potential to put the Baby Orangutan out of spec and damage the unit if the current demands are too, well, demanding.

- Ben