barathbushan
- Sep 26, 2009
- 223
- Joined
- Sep 26, 2009
- Messages
- 223
hi guys
I am constructing this toycar which can be wirelessly controlled from a pc with seria port (rs 232 interface) ,
the control signals [ W,S,A,D,E ] are sent as ascii characters from keyboard serially through terminal 1.9b software ,
the wireless communication is achieved by using rx-tx-434 mhz communication modules ,
transmitter connected to pc , and reciever connected to toycar as shown in the circuit diagram.
The project works like this when the microcontroller recieves a code say W , then it switches the 4 transistors on 1 1 1 1 ,
hence all relays drive the motors , when it recieves another character say E ,
then only one transistor is on hence only left motor is on 0 0 0 1,
driving the vehicle right , and so on with other moves .
TRANSMITTER [pc]
RECIEVER [toycar]
The actual problem is , the microcontroller is not recieving the data through its rxd pin ,
i know this because i have tested the modules by connecting the led between the data and
ground pin of both transmitter and reciever , and by sending data through the com port ,
both the led's flash in sync with the data indicating no problem .
Also by giving all the transistors 5 volts , all the relays were on indicating no problem ,
so the leftover suspect is the microcontroller .
I dont think there is any problem with the code since i downloaded the hex file into the chip ,
which was given in the magazine's CD .Also the logic of the code seems correct to me .
I even connected the the rxd pin of the µcontroller to the data pin of rs232 pin
and found no result .
my suspect for the problem is the max 232 interfacing , i mean its
different from standard connections , could this be the problem ???
I am constructing this toycar which can be wirelessly controlled from a pc with seria port (rs 232 interface) ,
the control signals [ W,S,A,D,E ] are sent as ascii characters from keyboard serially through terminal 1.9b software ,
the wireless communication is achieved by using rx-tx-434 mhz communication modules ,
transmitter connected to pc , and reciever connected to toycar as shown in the circuit diagram.
The project works like this when the microcontroller recieves a code say W , then it switches the 4 transistors on 1 1 1 1 ,
hence all relays drive the motors , when it recieves another character say E ,
then only one transistor is on hence only left motor is on 0 0 0 1,
driving the vehicle right , and so on with other moves .
TRANSMITTER [pc]
RECIEVER [toycar]
The actual problem is , the microcontroller is not recieving the data through its rxd pin ,
i know this because i have tested the modules by connecting the led between the data and
ground pin of both transmitter and reciever , and by sending data through the com port ,
both the led's flash in sync with the data indicating no problem .
Also by giving all the transistors 5 volts , all the relays were on indicating no problem ,
so the leftover suspect is the microcontroller .
I dont think there is any problem with the code since i downloaded the hex file into the chip ,
which was given in the magazine's CD .Also the logic of the code seems correct to me .
I even connected the the rxd pin of the µcontroller to the data pin of rs232 pin
and found no result .
my suspect for the problem is the max 232 interfacing , i mean its
different from standard connections , could this be the problem ???
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