io ho risolto cosi
int cmd_tx = 5 ;
int analogPin = 3;
int rx_val = 0;void setup()
{
pinMode(cmd_tx, OUTPUT);}
void loop()
{
rx_val = analogRead(analogPin);if (rx_val < 50)
{
digitalWrite(cmd_tx, HIGH);
}
else
{
delay(3000); //attendo 3 secondi
digitalWrite(cmd_tx, LOW);
}}