STEER WINNING ROBOTS
WITHOUT SERVOS!
Perform proportional speed, direction, and steering with
only two Radio/Control channels for vehicles using two
separate brush-type electric motors mounted right and left
with our mixing RDFR dual speed control. Used in many
successful competitive robots. Single joystick operation: up
goes straight ahead, down is reverse. Pure right or left twirls
vehicle as motors turn opposite directions. In between stick
positions completely proportional. Plugs in like a servo to
your Futaba, JR, Hitec, or similar radio. Compatible with gyro
steering stabilization. Various volt and amp sizes available.
The RDFR47E 55V 75A per motor unit pictured above.
www.vantec.com
Order at
(888) 929-5055
48 SERVO 08.2008
provide a way to control the speed. If you only want a
couple speeds, R1 could be selected with a relay or a
transistor controlling which values are used for the circuit.
With an adjusted PWM circuit, you can then have the
fun of building a vehicle with other Vex parts and watch it
run. Of course, you will need to have a way of starting and
stopping the car, but that’s a project for another day. SV
FIGURE 4
Parts List
• (1) Vex Robotics Motor Vex Robotics P/N 276-2163
• (1) LM555 Timer IC RadioShack P/N 276-1723
• (2) 4.7KW 1/4 Watt Resistor RadioShack P/N 271-1330
• (1) 10KW 1/4 Watt Resistor RadioShack P/N 271-1335
• (1) 1KW 1/4 Watt Resistor RadioShack P/N 271-1321
• (1) 1KW 15-turn Potentiometer RadioShack P/N 271-342
• (1) 1 µF Electrolytic Capacitor RadioShack P/N 272-1434
• (1) 0.01 µF Ceramic Capacitor RadioShack P/N 272-131
• (1) IN4001 Diode RadioShack P/N 276-1101
• (1) Battery Holder for four D-Cell Batteries RadioShack
P/N 270-396
• ( 4) D-Cell Batteries
