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Collaborative Robotics

How to build your own collaboration enabled robot
Printed circuit boards:

Our robot is designed to operate with a ring system, so is described in a few of the other related robotics pages. The idea is that any component in the ring can fail and everything will still be recoverable. We're actually working on a better version at the moment, but for now here's the original printed circuit board which we used to form each of the components.

If you want to view our scematics, you will need to downloadEagle.

We used a company called PCB Pool to print our circuit boards, and they were very good. They will also accept Eagle format directly, so if you wanted to get some boards made, you need only send the files, no need to edit them.

Firstly, the diagram below shows the generic sensor board, which you should expect to use for each component of your truck. We have one for motors (steering and speed), one compass and two ultrasonics (one back, one front separately).

The red lines are on the top of the board, the blue underneath. Although it's a lot more hassle, it is also possible to get kit to build your own PCBs. It takes a little while, and there's a bit of an equipment outlay (nothing huge, but you'll need a small drill, an iron, copper board, etching solution - most of which can be found at Farnell) but it depends whether you expect to occasionally do this sort of thing with different boards or not. It's handy for experimenting certainly, but the results can sometimes be a bit sketchy if you're not very careful.

The PIC chip which goes on here is the PIC16F628, in this diagram it would go with pin 1 in the top left corner. There should also be two 5 pin connectors (pins to the left) and potentially four 2 pin connectors on the right, although it's a tight squeeze so we've normally only connected two. These should have the pins towards the bottom of the diagram. Two transistors should be soldered into the two parallel rows of three holes in the centre bottom, the transistors should face in opposing directions. There are also three resistors.A 4k7 resistor goes between the two holes centre top (ignoring the top very long rows) which cross the track from pin 6. To the left of it you should solder a 2k2 resistor in the other set of holes. A second 2k2 resistor should be inserted to the right of the transistors.

Depending on whether you would prefer to make your own PCB or send off for them, you will need either the postscript file or eagle file below:

The rows of holes along the top of the board actually represent connections to the two ports, which is why we term this our generic sensor board. Port A is to the left and runs right to left, Port B is on the right and runs left to right (0-7). 

Once you have all the generic connections done for each board, you need only connect the specific cables to each device.

You should also bear in mind that the 5 pin connectors have (top to bottom) 0V, 5V, signal, free, free, and the two pin connector at the end have (left to right) 0V, 5V.

Our configuration:

Motors PB4, PB5, Compass PB4, ultrasound PA0-3, PB0-3.

We also have a hin232 converter chip for comms with the PDA serial port. See diagram below:

A DB9 connector connects to the right hand side here, with the bottom 4 pins all soldered together. On the left, two 5 pin connectors should be attached with pins facing left, and a hin232 chip on the main part of the board.