Orangutan X2 Servo Control

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1

Hi there,

I’ve been playing around with smaller robots in the 3-6V range using the low-voltage dual serial motor controller, however I’m looking to upgrade. I’m looking at getting a 4WD car with 12V independent DC motors for each wheel. It looks like they’ll be drawing a maximum of 5A each, resulting in 10A for the left and right channels. My plan was to purchase the Orangutan X2 as it’s looks perfectly suited for those power requirements while remaining nice and compact. My problem is that I’ll be driving several servos for sensor tilt and panning that run on 5-6V. The Vservo voltage on the X2 is likely to be about 10V, while the regulator outputs 5V but won’t be able to provide enough current. What are my options here for controlling and powering up to 4 or 5 servos?

The Micro Serial Servo Controller looks great but I don’t think I have access to the SPI lines on the X2. Is software serial a relatively simple solution? The robot will be powered by 2x6V NiMH cells so there will be 6V available, but the servo PWM will also need to be at the same voltage, and share a common ground, which could be a problem given the two cells are in series. I’d also rather keep them discharging at the same rate. The other option is a small switching regulator but the signalling is still an issue there.

I’m not really sure which way to go with this, I’ve also considered a baby orangutan or arduino with a TReX but I don’t really need the RC or analog control or the extra wiring.

Any advice or possible solutions are welcome.

Thanks

2

Hello,

Your project sounds fun! The main thing to point out is that your servo signal voltage does not have to be the servo supply voltage, so you can definitely use a 6V battery or the switching regulator to power the servos. Also, our serial servo controller uses asynchronous serial, which is available in hardware on the user AVR (ATmega644). For more than a couple of servos, I think it’s a good way to go since that’ll be one less timing constraint you’ll have, and you won’t need to worry about your servo jittering because you happened to be dealing with a higher-priority interrupt.

- Jan

3

Thanks for the quick reply Jan!

Looks like the serial controller is the way to go then, didn’t realize asynchronous serial was available on the IO with the ATmega644. Should have spent more time reading the datasheets :smiley:

Looks like I’ll be going ahead and ordering very soon then, you just have too many products I want to buy these days :wink: