How to connect two TCN75A temperature sensors with Arduino ?

Hello arduino enthusiasts :),

I recently bought Arduino Uno and I am trying to create a thermal regulator device. For this purpose I also bought two TCN75A thermal sensors. I am able to connect one of the sensors, and get the temperature readings, but I am not sure how to connect the second one. Here is what I have done so far:

Schematics:

  • SDA → ?4
  • SCL → ?5
  • Vcc → 5V
  • GND → GND

Code:

#include <Wire.h>

int reading = 0;
float temperature = 0;

void setup(){

Serial.begin(9600);
Wire.begin();

///// sets resolution for the measurement
Wire.beginTransmission(B1001000);
Wire.send(0x01);
Wire.send(0x60);
Wire.endTransmission();

Wire.beginTransmission(B1001000);
Wire.send(0x00);
Wire.endTransmission();
}

void loop(){

Wire.requestFrom(B1001000, 2);
reading = Wire.receive();

reading = reading << 8;
reading |= Wire.receive();

reading = reading >> 4;

temperature = (float)reading/16; // ??? ?? 16 ??? ???

Serial.println(temperature,3); // ??? ??? ? ?? ??? ???
// ? 3 ??? ??? ???

delay(500);
}

Thanks is advance.

Best regards

It’s a I2C (2 - Wire) device, so you need to arrange for them to be at different bus addresses, by wiring pins 5, 6 and 7 on the chip differently.
You should be able to have up to eight of them on a single bus - refer to the datasheet of the Microbot module.

I do not see the pullup resistors. This will become more important as you add more devices. I suggest some background reading, for example: http://tronixstuff.com/2010/10/20/tutorial-arduino-and-the-i2c-bus/

It's working :). Thanks for the help guys !