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Al1970
01-10-2009, 12:39 AM
The Features Of The Servo Controller

The kit comes with a prototype board, servo controller
chip, jack, wire and all the other parts you need. The
board is voltage regulated so it can be connected to 4.5
volt up to 9 volts. The "VEX" type of motor uses 9 volts.
The servo connectors are make from dip sockets since both
male and female are needed.

The Servo Controller board is meant to be used in robots
where a servo has been changed so that it can run like a
motor. You can find many sites that will show you how. Use
the joysticks on the "VEX" transmitter for that
Use the buttons on the "VEX" transmitter to controller any
unchanged servos in your robot. The buttons will give you
better control over the servos than the joystick
This controller chip can control up to six servos. It can
control them by receiving a serial command from another
microcontroller. You can also radio control the servos thru
a "Vex" receiver.

You can radio control the "VEX" servos and motors as well
as many other brands of servos by setting the pulse width
range on the servo controller chip. The servo controller
chip also gives you an option of what to do if your robot
goes out of radio control range or if you turn the
transmitter off.
It can center the servos to the normal postion or it can
put a high on the servo's input signal lead thereby turning
the motor in the servo off. If you are using another
microcontroller, the servo controller will take commands
from that microcontroller
while still monitoring for a radio signal. Once a radio
signal has been detected; the servo controller lets the
radio control to take over again.
The "VEX" microcontroller turns the "VEX" servo all the way
to the left or right while the button was pressed and then
back to the center when the button was released.
This didn't seem to me to be very useful. With my servo
controller, the servo slowly turns while the button is
pressed. When the servo is in the postion you want, release
the button and the servo remains in that postion. This
would allow you to do something like raise the robot's arm
to where you want it then free your hands so that you can
control another joint.
Pin Summary

Input Pins
Pin 1 If it goes low it does a rest (MCLR)
Pin 16 From "VEX" receiver
Pin 12 Serial input from another microcontroller
Pin 17 Option, pulse width of 1.5 ms or high
Pin 20 Ground to chip
Pin 1 + voltage to chip
Pin 19 Connect to + voltage
Pin 18 Connect to + voltage
Pin 3 Option, servo pulse range
Pin 11 Option servo pulse range

Output Pins
Pin 9 When high tells the other microcontroller it can
send the next command
Pin 2 Goes high if a command error has been detected
Pin 10 Spare
Pin 13 Spare
Pin 15 Servo 1 pulse output
Pin 14 Servo 2 pulse output
Pin 7 Servo 3 pulse output
Pin 6 Servo 4 pulse output
Pin 5 Servo 5 pulse output
Pin 8 Servo 6 pulse output

List Of The Commands

There are 6 commands that the Servo Controller chip
understands. All the commands are 2 bytes long. The format
for the commands are as follows.
The 1st byte that is sent is always the data byte which
is a number in the range 10 to 251
A number higher than 250 will put a high on the Servo
Controller servo output. This will cause the servo's motor
to lose power.
Every count of 2 makes the pulse width .02 ms longer. The
Servo Controller can take up to 4 commands every 20 ms.

The 2nd byte that is sent is always the command byte. The
number range is 1 to 6.
For example:
To order servo 1 to go to center, the command would be. 150
1
Servo 1 PW #, 1
Servo 2 PW #, 2
Servo 3 PW #, 3
Servo 4 PW #, 4
Servo 5 PW #, 5
Servo 6 PW #, 6
You will get much more information when you buy the kit
which cost $28.23 + S/H $6.00 I take PayPal; you can send
payments and questions to my e-mail address.