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[on:]

Hello to all.... I am interfacing a Heart Rate Sensor from Nonin (the Xpod) and the sensor sends 3 bytes once a second, I receive 3 bytes, but completely wrong, don't know why. I'm doing a passtrough but don't know why... I expect to receive <163><127><127> and I receive <46><64><64>.... do you know why?... I'm working with the Arduino Mega 2560, and using a Hardware UART on it (N°1), the sketch is very simple

Code:

char incoming_char;

void setup{
   Serial.begin(9600);
   Serial1.begin(9600);
}

void loop{
  
    if(Serial1.available()){
      incoming_char()=Serial1.read();
      Serial.print(incoming_char);
      }

}

Any help will be appreciated... Or some example sketch will be very very useful.... Thanks to all....

[Reply #1 on:]

What sort of output has your Heart Rate Sensor. Is it RS232?
If so then you need a level converter chip like a MAX202 to convert the RS232 signal levels into TTL signal levels. The level translation also includes a logic inversion and this is why you are seeing rubbish data.

[Reply #2 on:]

All that Nonin says is "The output is TTL"... that is weird....because the Mega (and all arduino boards) have TTL UART's.... any ideas?. By the way, I have a logic level converter form Sparkfun Electronics...

[Reply #3 on:]

Solved: I disconnected the level shifter on the Xpod evaluation cable and now everything is fine.

Thanks to all!