Making a robot work with the tiny computer Raspberry Pi or RBPi has never been so easy. If you use the RBPi robot kit GoPiGo, all you will need is a small screwdriver with a Phillips head. The GoPiGo kit comes in a box that contains a battery box for eight or 6 AA batteries, two bags of hardware, two bags of acrylic parts, two motors, the GoPiGo board and a pair of wheels. For assembling all this into a working robot, follow these step-by-step instructions.
You start with the biggest acrylic part in the kit, the body plate or the chassis of the GoPiGo. Lay the plate on the GoPiGo circuit board and align the two holes with those on the circuit board. Place two short hex spacers in the holes below the body plate to make sure of which way is the upper side.
Next, you must attach the motors to the chassis. Use the four acrylic Ts in the kit for attaching two motors. Do not over tighten the bolts while attaching the motors, as this may crack the acrylic.
With the motors in place, it is time to attach the two encoders, one for each motor. These encoders fit on the inside of the motors and poke through the acrylic chassis of the GoPiGo. Encoders are an important part, providing feedback on speed and direction of rotation of the motor. If the encoders will not stay on, use blue ticky tacky to make them stay.
Now it is time to attach the GoPiGo board to the chassis. Place the GoPiGo board on the spacers and line its holes with the holes in the board before holding them together with screws. Two hex supports on the back of the GoPiGo board allow you to attach the castor wheel.
That brings us to attaching the wheels to the GoPiGo. You must do this gently, backing the wheels so they do not touch or rub against the screws. The battery box comes next, to be placed as far back on the chassis as possible. This gives it extra space and prevents the box from hitting the SD card on the RBPi.
This completes the mechanical assembly of the GoPiGo robot and only the RBPi remains to be attached. Locate the black plastic female connector on the GoPiGo and slide the GPIO pins of the RBPi into this connector. The RBPi remains protected by a protected plate or a canopy that has to be attached by screwing it on to the chassis.
Make the electrical connections according to the instructions. Be careful while flashing the GoPiGo hardware and leave the motors unconnected during the flashing. After connecting the GoPiGo for the first time, if you find any motor running backwards, simply reverse its connector.
GoPiGo comes with an ATMega 328 micro-controller, operating on 7-12VDC. SN7544 ICs handle the motor control part, which has two optical encoders using 18 pulse counts per rotation and a wheel diameter of 65 mm. External interfaces include single ports of I2C, Serial, analog and digital/PWM. The idling current consumed is about 3-500 mA, and full load current is 800 mA – 2A with both the motors, the servo and the camera running with the RBPi model B+.