Boards

As you can see in the 3D modelisation, the robot's chassis is constituted of electronic boards. They are light, resistant and useful :)

The robot will be constituted of 8 PCBs:

• the main board, top
• the bottom board, with sensors to detect zones on the table
• the camera board, front
• a utility board, back, to add some rigidity and to support the bluetooth module
• two boards to support the coder wheels (inside)
• two little boards on the sides to connect electrically top and bottom boards

Main board

This is the brain of the robot. It hosts a dsPIC33F (with integrated hardware quadrature decoders), several sensors (accelerometer, gyroscope, magnetometer), a big flash memory to log all the events of a match (to be able to analyze them later).
On top of this board sits a tiny Nokia LCD that will serve to display information for the man-machine interface when programming/debugging, and that will serve as an emergency stop button during matches (mandatory).
The top board will also host an IR sensor for the start switch, a mini-USB slot, LEDs and so on.

Bottom board

This board is the chassis, truly speaking. It supports two fuse holders, to place the motors in.
Underneath, several IR sensors will be present to be able to detect the starting zone (to be able to localize the robot precisely before the match starts) and the container hole (to avoid falling in it).
The H-Bridge for the motors will be on this board too, to reduce the length of power wires (to reduce noise).
This board will also support a boost power supply, to generate 6 or 7V from the single cell LiPo battery, to drive the motors and the LCD backlight LEDs.
Finally, the LiPo charger chip will also be hosted on the bottom board.

Utility board

The main reason this board exists is to reinforce the robot, by connecting the top and bottom boards.
Since I have enough room on the back, this board will host a piezo capsule (to be able to localize the bot if I lose it !) and the bluetooth module that will act as a serial link between the computer and the robot when programming.

Coder board

The coder wheels are each on a separate board, hosting the quadrature IR barrier (from an old ball mouse).
They are pushed onto the driving wheels rubber tire with strong springs to accurately measure the robot's moves.
The quadrature signals are then fed in the main board's dsPIC to be able to track the robot's position.

Camera board

This board supports the camera as well as another dsPIC33F to analyse the data stream coming from the cam. This assembly acts as a simple sensor that will tell the main CPU if there is something red in front of us, and its approximate position (far left, left, and so on...) to be able to drive the robot towards red balls.

Side boards

Their only utility is to strengthen the chassis and the assembly, while electrically connecting some signals between top and bottom boards.

Components

A list of all sensors can be found here: Sensors

Of course most of the components are SMD, many of them not easily soldered by hand (I use dsPIC in QFN package to save space for instance). I plan to use a home-made reflow oven to solder them, or maybe even a frying pan :)

Shops

http://www.totalrobots.com/ for solarbotics stuff (port is awfuly expensive form solarbotics !)
http://www.sparkfun.com/ for all I need
http://www.pololu.com/ for small-sized IR sensors