Hello everyone,
I’m posting my feedback on the GoPiGo hoping it helps the project move forward.
Summary:
Kit: GoPiGo Basic bought Sept. 17,2015. with Raspberry Pi: 2
Firmware: 1.3 (upgraded)
Accesories: Added the Picamera and a Servo (TowerPro SG90) on Sept. 29.
Batteries: BK-3MCCA4BA eneloop AA New 2100. 1.46V when fully charged.
Storage: Kingston 16GB Class4 (SDC4/16GBET).
Python Exp: Beginner, mostly a copy paster from examples found on the net.
Challenges thus far:
1- As noted by forum members, the Rasp 2 sits at a slight angle due to one of the capacitors that rests on the HDMI port. I’ve put a piece of black electrical tape on top of the cap so it doesn’t make contact with the HDMI port.
2- The power connector doesn’t have enough clearance due to the Micro USB from the Rasp 2. I took the connector apart and used a dremel to cut 20% off of it and I also bent the pins outwards slightly.
3- The caster wheel that came with the gopigo seems defective. The ball gets stuck all the time since day one. It also picks up all the cat’s fur and turns it into an oily mess 
4- One of the GoPiGo’s yellow wheels moves all over the place while rotating.
5- The servo misbehaves while operating it on Batteries. Using batteries + Micro USB doesn’t trigger it. One of the LEDs also turns on when servo is being operated and stays light for a while. The servo jitters after completing the movement and stays on for about 4 seconds.
a- Troubleshooting:
Executing “disable_servo()” right after servo(x) seems to be a quick fix.
5- The GoPiGo rarely rolls in a straight line. Most of the times it’s due to the caster wheel that doesn’t easily clear the tile grouts but there are also times when I think it’s either the Wheel or something else…
a- Troubleshooting:
I did the encoder test, all seems fine.
I did a trim test, added +5 once but recently took it off.
I checked the voltage while motors are FWD() at set_speed(255) while volt() returns 10.42v. Both motors report: 8.4V on the multimeter.
I checked the voltage without motors connected while at FWD(), same speed: 9.4V on the multimeter on both motors.
Servo Jitter example (noticeable at the end): https://youtu.be/vpRnXBVCmKw
Currently trying to find a replacement for the caster wheel. Any recommendations are welcome!