Little autonomous robot V2

Written by Administrator, on 27-10-2007 11:26

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This page described my new robotic project. One year ago, I built a very simple little robot with a Comfile PICBASIC 3B microcontroller and a Cybot chassis. This new project is based on a very much more powerful Microchip PIC 18F4620 (or PIC18F4520) Microcontroller programmed in C language with the same chassis and new sensors..

This is still work in progress, but the MCU board, the sensors board and the motor board are still ready and pictures and schematics are available on this site.

Specifications:

Microchip PIC 18F4620 MCU
Motors drive by SN754410 H-bridge (Texas Instruments)
Sharp GP2D02 distance measuring sensor mounted on servomotor for sweeping

1 microswitch for chocs detection, and 2 infrared proximity sensors
HP48 with terminal emulator for display and commands
Cybot chassis (motors and wheels)

The IR proximity sensor:

Its a very classical device, build with a Vishay TCRT5000 IR led/phototransistor and NE567 tone decoder.

IRschem IR picture

C1=1uF, C2=470n, C3=C4=C5=100n; R1=R2=R5=10k, R3=100,R4=100k; IC1=NE567

To avoid interferances between devices, you can change the R4 value.

The Motor control board

The motor board is based on the SN754410 H-bridge (Texas Instruments). It's drived by PWM signal from the MCU. To lines come from the MCU board for PWM signal, and 2 lines for direction control.

The MCU board

Based on 18F4620 MCU, Analog devices ADM203 for RS232 communication, ICSD (Olimex) connector.

(click to enlarge)

The chassis

It's still the Cybot chassis. Cybot was a robot sold in kit form in a magazine. It's a very cheap chassis (~10 euros) because it's just necessary to buy the two firsts issues to get motors, reductors and wells. It's still possible to buy these magazine (in europe) on there website