New to GoPiGo


#1

Hello,

I just started experimenting with the GoPiGo, primarily focusing on the worm brain, with the intention to do something with Windows 10 as it matures on the Pi. Yes, I have already ran the current win10/Pi and I am an experienced developer in the types of apps it needs (ie C#/XAML/Windows Universal).

Just for reference, here are some pics of my ‘worm’ and my other more serious robot (http://www.spiked3.com/the-worm-and-his-bigger-cousin/);

worm gopigo

spiked3.com bot

So, I have noticed some behavior I am trying to understand, and was hoping maybe someone had been through this and could summarize it for me?

I ran the samples that came with the img file, and had some issues, so I git pulled the current, and installed the v14 firmware. All seemed ok on a weak battery, so I finished the build. While I was doing some customization I was running the Pi off the USB only power, while the big battery was charging. I first noticed that on a stop command, one wheel would spin. I looked around and could not find a reason so I re-flashed v14. That stopped the wheel from spinning. Then when I hooked up the charged battery, the other wheel (I am pretty sure) started spinning, so again, re-flashed. Fixed again. It almost seems as though ‘neutral’ depends on battery/power level at the time of the flash, or something like that. Is it my imagination or is there some connection? If there is a connection, is there a way to easily swap between 2 configurations? Or is it something else entirely?

Anyhow, I will try to spend the rest of the day adding a hotspot to my worm to make it easily demonstrable at events.

Cool robot.


#2

Hey thanks for your letting us know what you’re up to with the GoPiGo! Nice lookng robot!

I don’t know if it’s anything to do with the batteries. If you’re running the GoPiGo and motors on just the USB power though, you can start to see funny things happening with the atmega and possibly with the GPG. The motors will draw a lot of amperage, comparatively, and this can cause the voltage to drop on your USB power supply. That might interrupt or disturb something in the firmware.

We would strongly recommend against running the motors with a USB power supply!


#3

I agree on not running motors on a USB supply, that is why I was surprised to find it wired that way. I would recommend against that in future board revisions. This might also explain some of the noise problems you are having. I am running 4 larger motors, drawing much more current, and handling MPU6050 gyro/accelerometer traffic on I2C with no issues at all, or need to slow down my code or clock anywhere.