#include "Wire.h" #define TMP102\_I2C\_ADDRESS 72 /\* This is the I2C address for our chip. This value is correct if you tie the ADD0 pin to ground. See the datasheet for some other values. \*/ void setup() { Wire.begin(); // start the I2C library Serial.begin(115200); //Start serial communication at 115200 baud } void loop() { getTemp102(); delay(5000); //wait 5 seconds before printing our next set of readings. } void getTemp102() { byte firstbyte, secondbyte; //these are the bytes we read from the TMP102 temperature registers int val; /\* an int is capable of storing two bytes, this is where we "chuck" the two bytes together. \*/ float convertedtemp; /\* We then need to multiply our two bytes by a scaling factor, mentioned in the datasheet. \*/ float correctedtemp; /\* Reset the register pointer (by default it is ready to read temperatures) You can alter it to a writeable register and alter some of the configuration - the sensor is capable of alerting you if the temperature is above or below a specified threshold. \*/ Wire.beginTransmission(TMP102_I2C_ADDRESS); //Say hi to the sensor. Wire.write(0x00); Wire.endTransmission(); Wire.requestFrom(TMP102_I2C_ADDRESS, 2); Wire.endTransmission(); firstbyte = (Wire.read()); /\*read the TMP102 datasheet - here we read one byte from each of the temperature registers on the TMP102\*/ secondbyte = (Wire.read()); /\*The first byte contains the most significant bits, and the second the less significant \*/ val = firstbyte; if ((firstbyte & 0x80) > 0) { val |= 0x0F00; } val <<= 4; /\* MSB \*/ val |= (secondbyte >> 4); /\* LSB is ORed into the second 4 bits of our byte. Bitwise maths is a bit funky, but there's a good tutorial on the playground\*/ convertedtemp = val\*0.0625; correctedtemp = convertedtemp - 5; /\* See the above note on overreading \*/ Serial.print("firstbyte is "); Serial.print("\t"); Serial.println(firstbyte, BIN); Serial.print("secondbyte is "); Serial.print("\t"); Serial.println(secondbyte, BIN); Serial.print("Concatenated byte is "); Serial.print("\t"); Serial.println(val, BIN); Serial.print("Converted temp is "); Serial.print("\t"); Serial.println(val\*0.0625); Serial.print("Corrected temp is "); Serial.print("\t"); Serial.println(correctedtemp); Serial.println(); }
