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root / quad2 / arduino / src / ros_lib / examples / Temperature / Temperature.pde @ c1426757

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1 c1426757 Tom Mullins
/*
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 * rosserial Temperature Sensor Example
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 * 
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 * This tutorial demonstrates the usage of the
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 * Sparkfun TMP102 Digital Temperature Breakout board
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 * http://www.sparkfun.com/products/9418
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 * 
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 * Source Code Based off of:
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 * http://wiring.org.co/learning/libraries/tmp102sparkfun.html
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 */
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#include <WProgram.h>
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#include <Wire.h>
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#include <ros.h>
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#include <std_msgs/Float32.h>
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ros::NodeHandle  nh;
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std_msgs::Float32 temp_msg;
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ros::Publisher pub_temp("temperature", &temp_msg);
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// From the datasheet the BMP module address LSB distinguishes
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// between read (1) and write (0) operations, corresponding to 
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// address 0x91 (read) and 0x90 (write).
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// shift the address 1 bit right (0x91 or 0x90), the Wire library only needs the 7
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// most significant bits for the address 0x91 >> 1 = 0x48
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// 0x90 >> 1 = 0x48 (72)
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int sensorAddress = 0x91 >> 1;  // From datasheet sensor address is 0x91
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                                // shift the address 1 bit right, the Wire library only needs the 7
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                                // most significant bits for the address
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void setup()
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{
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  Wire.begin();        // join i2c bus (address optional for master) 
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  nh.initNode();
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  nh.advertise(pub_temp);
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}
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long publisher_timer;
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void loop()
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{
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  if (millis() > publisher_timer) {
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  // step 1: request reading from sensor 
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    Wire.requestFrom(sensorAddress,2); 
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    delay(10);
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    if (2 <= Wire.available())  // if two bytes were received 
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    {
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      byte msb;
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      byte lsb;
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      int temperature;
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      msb = Wire.receive();  // receive high byte (full degrees)
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      lsb = Wire.receive();  // receive low byte (fraction degrees) 
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      temperature = ((msb) << 4);  // MSB
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      temperature |= (lsb >> 4);   // LSB
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      temp_msg.data = temperature*0.0625;
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      pub_temp.publish(&temp_msg);
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    }
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  publisher_timer = millis() + 1000;
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  }
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  nh.spinOnce();
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}