Serial communication

Hello there,

I created a the link

Code:

sudo ln -sf /dev/ttymxc3 /dev/ttyS0

Then, I wrote

In Debian

Code:

#!/usr/bin/python

import time
import serial
import commands
arduino = serial.Serial('/dev/ttyS0', 9600)
print("Hablando con Duino")
while True:
   comando = 'H' #Input
   arduino.write(comando) #Mandar un comando hacia Arduino
   if comando == 'H':
      print('LED ENCENDIDO')
   elif comando == 'L':
      print('LED APAGADO')
   break
arduino.close() #Finalizamos la comunicacion
time.sleep(4)
#output=commands.getoutput('sh /usr/bin/foto')

In Arduino

Code:

int comedero = 3;
int piloto = 13;

void setup() {
pinMode(comedero,OUTPUT);
pinMode(piloto,OUTPUT);
Serial.begin(9600);

}
void loop () {
if (Serial.available()) {
char c = Serial.read(); 
if (c == 'H') { 

digitalWrite(comedero, HIGH);
delay(3000);
digitalWrite(comedero, LOW);
}

if (c == 'W') { 
digitalWrite(piloto, HIGH);
}
if (c == 'S') { 
digitalWrite(piloto, LOW);
}
}
digitalWrite(comedero, LOW);
}

But the LED i've put on the pin 3 of the UDOO doesn't go high, but it does when I upload the blink (changing pin 13 of the example to the 3 pin)

 

Why don't you use directly /dev/ttymxc3 in the python script? This could make the trick...

 

The communication channel between Arduino and ubuntu or else , in udoo, is the serial port /dev/ttymxc3

 

then in java or python you have to implement one or two threads to syncronized the communication and to close the port when you exit the application , otherwise you will have the serial port busy and not available for other application such as Arduino