Photo6 Page

Board 1 - motor driver board
This essentially drives the motors from the 4xAA batteries, but using the 9v logic inputs from the rest of the circuitry. This circuit board also contains two LEDs (lights), these indicate when the batteries are low. It's connections are as follows:
Pin 1 right motor +ve
Pin 2 right motor -ve
Pin 3 left motor +ve
Pin 4 left motor -ve
Pin 5 +5v regulated
Pin 6 +ve 6volts
Pin 7 Ground

Board 2 - connection board and line following processor
This provides connectors for the LDRs (light sensors), line following unit, left and right antennae, and buzzer/piezo speaker. The 8pin chip is a 311 type op amp. It's job is to control cybot's motors during line following mode, because this chip is used in this configuration, it can only say go left or right to the motor board and this is why Cybot has its characteristic zigzag movement as it goes along the line. Board 2 connects to the third and last board of the lower level by a 13 pin connector.

Board 3 - light processing board
The chip on the light processer board for the trial group is a PIC16C505. For the national release of the magazine the chip will be an EMC, no part number is available yet. This type of chip is not reprogrammable and so we won't be able to adjust Cybot's program this way. The PIC16C505 is a 14 pin chip with 1024x12bit program memory and 72 bytes of RAM. It is a low cost RISC-based 8-bit CMOS microcontroller. The chip has 12 I/O pins which can each sink/source 25mA. The other two pins are used for the power connection to the PIC. Unfortunately this PIC is copy protected so we won't be able to extract the code from it to understand how it works. The chips in Cybot are likely to be mask programmed at the factory, as this is getting cheaper and lots of these chips are needed for the Cybots worldwide.

Board 3b - line following sensor board
This board sits in Cybot's nose and it detects a line which it can follow. Board 2 contains the simple processor which decides which way Cybot should go. The sensor board consists of a pair of phototransistors/Infra-red LEDs. Depending on whether Cybot is on its black line or not, the sensors send back different signals to the chip on board 2 and the op-amp adjusts Cybot's movement so it stays on the line

Board 2a - Sonar Processor board
Perhaps the most visually boring board so far, this board contains one PIC chip, a PIC16C505. This board provides all of the processing needed for the sonar avoid/follow modes.

Board 3 - Sonar I/O board
This provides connections for the sonar transmitters and receivers, as well as the all important more selecting toggle switches. It contains an onboard comparator chip, the LM393.

The two presets adjust the sensitivity on the input amplifiers to prevent feedback.
Adjusting the sensitivity affects Cybot's depth of vision, but this is a side affect rather than an intentional feature. The presets are in theory adusted so maximum gain can be obtained while keeping the internal feedback of the amplifier as small as possible.

The four small "toggle" switches activate different modes when placed in different orders: Issue 14+ modes:
0000 = light follow
1100 = slow avoid objects

Issue 16+ modes:
1000 = slow light follow
0100 = avoid objects
0110 = follow objects

By Cybot's completion it will have 5 processors and there will be 3 processors on the remote control handset. In addition to these there will be an E2PROM chip, which will contain Cybot's instructions during programming. This chip can be reprogrammed electronically, which means it is suitable for the task, unlike a fixed code chip, which would be useless.

Connections:
13 pins to Sonar Processor board (same level)
Left sonar transmitter
Left sonar receiver
Right sonar transmitter
Right sonar receiver

Inputs: Left preset Right preset 4 "toggle" switches

Thje new phase 2 remote