I can't figure out why the next script is not working. I have attached the Arduino to one USB port of the raspberry pi, in which I've installed pyserial. I just want to turn off/on a led depending of the number I write on the Raspi console (1-> on, 2-> off).

    int led=13;

void setup(){
void loop(){
     mode(Serial.read() - '0');  
void  mode(int n){

    if (n== 1){
    if (n== 2){

PS: I double checked and the baudrate is configured also at 115200 at the raspi side. In addition, if I place digitalWrite(led,HIGH) just before the line "mode(Serial.read() - '0');" the led turn on when I send some information from the raspi shell (so, works well).


1 Answer 1


Finally I've found the error, it was the serial communication baud rate: 115200. It seems that at higher speeds it not works properly, lowering it to 9600 do the trick.

  • 1
    Have you also tried other rates that worked (or not) between 9600 and 115200 bauds?
    – jfpoilpret
    May 3, 2014 at 11:55
  • That is weird. Anyone know why that's happening?
    – asheeshr
    May 3, 2014 at 14:18

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