Hey Ytai,,

Your description below says that you used two(2) A4988 Stepper Motor 
Driver<http://www.pololu.com/product/1182>.  
You also indicate that you are using a 2-cell Lipo battery.  However, the 
stepper driver requires an minimum operating voltage of 8V so how are you 
powering those drivers?  Would it be better to use the DRV8834 Low-Voltage 
Stepper Motor Driver <http://www.pololu.com/product/2134> instead? 




On Monday, May 14, 2012 12:06:37 AM UTC-7, Ytai wrote:
>
> It should be able to move forward and backwards and turn. I haven't yet 
> played around with it enough, but just did some preliminary tests and I'm 
> pretty confident it is easy.
> I had a previous attempt for a self-balancer based on continuous standard 
> hobby servos. I found that the backlash in the gears is problematic. This 
> time around I chose steppers and I'm very pleased with that. They have 200 
> steps / rev times 16 microsteps = 3200 positions / rev. They are very 
> torquey without needing gears, so I can direct drive these big 90mm wheels 
> with no problem and get high torque and precision. I initially used smaller 
> steppers that didn't deliver. Then I bought these two 
> beasts<http://www.pololu.com/catalog/product/1200>with these 
> drivers <http://www.pololu.com/catalog/product/1182>. The important thing 
> was that their voltage rating is low and their current rating is high. That 
> means I can connect them to higher voltage and let the driver do current 
> limiting, which is what also allows for microstepping.
> Other than that - no specs - that's all the robot: steppers, drivers, 
> 2-cell Lipo, IOIO, Nexus S and a kid-size Keens shoe box :)
>
>

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