Hello all

I have just started working on a final project for the third year of my 
technologist diploma and was wondering if i  could get some help with some 
PIC programming.

The project consists of voice recognition software that i have already 
written. Spoken commands into the PC's mike will control a remote device 
using a (one way) RF link. At the recieving end of the link i am using a PIC 
18f452 to control a servo (for steering) and a small DC motor for the drive. 
The spoken commands will be converted into  2 ASCII characters representing 
a hexadecimal code that will set the speed and direction of the DC drive and 
control the servo for steering.

The two character ASCII will be sent to the PIC's UART and compared to 
preprogrammed control characters that will be implemented to run the device.

What i need help with is the algorithm for the steering (servo). The servo 
has been torn apart and the circuitry removed. All that is left is the DC 
motor and the Potentiometer. Now i have to implement a feedback loop based 
on the setpoint(direction required) and the error signal(difference between 
the setpoint and the reading from the potentiometer). I am not quite sure 
how i will do  this using some form of PI control and a small deadband. Any 
help or ideas would be greatly appreciated since i don't have any experience 
with servos or PCM which has to be sent to the motor to control direction.

I also seem to be having problems with the RF link. I made up a null modem 
cable and have been testing the link between two PC's using hyperterminal on 
both ends. I can recieve the characters properly when i hold down the key. 
There is one exception though, when the key is first pressed i get a garbage 
character at the start of the stream and when i press and release a key, all 
that i manage to get is a garbage character. I also modified the MSComm 
example program to send a string of characters all at once. When this is 
done i just get garbage characters even though the baud rates are the same. 
Any suggestions or ideas would be greatly appreciated.

Thanks
Jason


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