From: sab@cruzio.com Subject: Using 7404's as Servo Motor H-Bridge Driver Organization: Cruzio Community Networking System, Santa Cruz, CA Date: Sat, 21 Oct 1995 20:38:27 GMT Keywords: servo hbridge motor driver Servo Motor, H-Bridge replacement: where o=connection (=no connection .-----o-----o----------------o-----o-----o--o----- Motor Red | | | | | | `--------. | | | .-----------(--o--(--o--(--o---|<---(--. | | | | | | | | | | 1n914 | | .--------o--(--o--(--. | | .--------o | | | | | | | | +Vcc | | | | | | | | +Vcc | | | | | | | | | __|__|__|__|__|__|__|_ | | __|__|__|__|__|__|__|_ | | | | 14 13 12 11 10 9 8 | | | | 14 13 12 11 10 9 8 | | | | | -|>o- -|>o- -|>o-| | | | -|>o- -|>o- -|>o-| | | | ) 7404 Hex Inverter | | | ) 7404 Hex Inverter | | | | | -|>o- -|>o- -|>o- | | | | |>o- -|>o- -|>o- | | | | | 1 2 3 4 5 6 7 | | | | 1 2 3 4 5 6 7 | | | | `--|--|--|--|--|--|--|-' | | `--|--|--|--|--|--|--|-' | | | | | | | | | GND | | | | | | | | GND 1n914 | | `-----(--o--(--o--(--o----o--' `-----(--o--(--o--(--o------|<---' | | | | | | | | .-----------' TTL DIR----o-----o-----o `-----------o-----o-----o-----o--- Motor Black Finding it hard to find those 'popular' motor driver IC's? Have a couple of 7404's and 1N914 diodes collecting dust? This circuit is TTL driven from the TTL DIR level. It combines the inverters in a series/parallel circuit with a couple of steering diodes to provide forward and reverse voltage across the servo motor. It will provide about 150ma of current. I have driven it from a 555 timer using up to 7.5V for +Vcc. NOTE: The servo motors were modified to allow 360 degree turning with no electronic 'guts' except for the motor and gears. - SAB -- ************************************************************************** Welcome to the Poor Man's site for Robotics " How do you modify $7.99 R/C car into a SABot for $20 "