Sending data from two analog input sensors out of the serial port...

Projects Programming
1

HI,

I have an analog sensor that I am reading and sending the data out of the serial port to MaxMSP softare, where I am analyzing the code.

Is it possible to add another analog sensor to this and send the data from both sensors through the serial port? Is there a way to ID the data streams so that I can separate them in Max? I have been looking and haven't been able to see any solution.

I will put the code I have below. Thank you in advance for any suggestions.

#define Version 11 // version, 1.0 or 1.1, which depands on your board you use as it is
const int pinO2 = A0; // Connect Grove – Gas Sensor(O2) to A0.   GSR sensor

#if Version==11
const int AMP = 121;
#elif Version==10
const int AMP = 201;
#endif

float sensorValue;
float sensorVoltage;


const float K_O2 = 7.43;
float Value;
float previousValue = 10;



void setup()
{
  Serial.begin(115200); //Start the Serial connection
}

void loop()
{

  sensorValue = analogRead(A0);
  sensorVoltage = (sensorValue / 1024.0) * 3.3;
  sensorVoltage = sensorVoltage / (float)AMP * 10000.0;
  Value = sensorVoltage / K_O2;

  // only transmit Value_02 if the input has changed

  if ( Value != previousValue) {
    previousValue = Value;
    Serial.println(Value, 3);
  }

}
2

Is it possible to add another analog sensor to this and send the data from both sensors through the serial port? Is there a way to ID the data streams so that I can separate them in Max?

Of course you can

What sort of ID would you like to use ? You can tag each value with an ID of your choosing by simply sending the ID via serial. It would be a good idea to use start and end markers for each ID/data pair to make it easier to parse at the other end

3

The serial input basics tutorial should give you some ideas.

Get the value from the second sensor and send the 2 readings (float data type) in a packet like:

Serial.print("<");  // start marker
Serial.print(fiirstValue, 3);
Serial.print(",");  // delimiter between values
Serial.print(secondValue, 3)
Serial.println(">");  end marker and \r\n
4

Hey GroundFungus,

Ok I'm looking at your code. That looks interesting. I guess on the receiving end I'll get:

< sensor value 1, sensor value 2 >

right? Then in Max I can take that list and separate it into two different numbers that I can work with. And I can probably remove the <,>.

Thank you very much for the help I'll try this out.

I did look in the tutorial and didn't see much about sending numbers, only receiving them, but I just did a quick scan, as there is a lot of stuff there. Anyway I'll try this. Thank you again.

Nick

Nick

5

I did look in the tutorial and didn't see much about sending numbers, only receiving them, but I just did a quick scan, as there is a lot of stuff there. Anyway I'll try this. Thank you again.

Yes. the tutorial is about receiving strings and numbers, but I think that it also give insight into how to send data packets for reliable reception. Framing the data with start and end markers, for instance.