Diff: examples/Temperature.cpp

Revision:

0:cb1dffdc7d05

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/examples/Temperature.cpp	Sun Feb 15 10:54:04 2015 +0000
@@ -0,0 +1,78 @@
+//#define COMPILE_TEMPERATURE_CODE_ROSSERIAL
+#ifdef  COMPILE_TEMPERATURE_CODE_ROSSERIAL
+
+/*
+ * rosserial Temperature Sensor Example
+ *
+ * This tutorial demonstrates the usage of the
+ * Sparkfun TMP102 Digital Temperature Breakout board
+ * http://www.sparkfun.com/products/9418
+ *
+ * Source Code Based off of:
+ * http://wiring.org.co/learning/libraries/tmp102sparkfun.html
+ */
+
+#include "mbed.h"
+#include <ros.h>
+#include <std_msgs/Float32.h>
+
+ros::NodeHandle  nh;
+
+std_msgs::Float32 temp_msg;
+ros::Publisher pub_temp("temperature", &temp_msg);
+
+
+// From the datasheet the BMP module address LSB distinguishes
+// between read (1) and write (0) operations, corresponding to
+// address 0x91 (read) and 0x90 (write).
+// shift the address 1 bit right (0x91 or 0x90), the Wire library only needs the 7
+// most significant bits for the address 0x91 >> 1 = 0x48
+// 0x90 >> 1 = 0x48 (72)
+
+ int sensorAddress = 0x91 >>1;  // From datasheet sensor address is 0x91
+
+// shift the address 1 bit right, the Wire library only needs the 7
+// most significant bits for the address
+
+Timer t;
+I2C i2c(p9, p10);        // sda, scl
+
+int main() {
+    t.start();
+
+    nh.initNode();
+    nh.advertise(pub_temp);
+
+    long publisher_timer =0;
+
+    while (1) {
+
+        if (t.read_ms() > publisher_timer) {
+            // step 1: request reading from sensor
+            //Wire.requestFrom(sensorAddress,2);
+            char cmd = 2;
+            i2c.write(sensorAddress, &cmd, 1);
+
+            wait_ms(50);
+
+            char msb;
+            char lsb;
+            int temperature;
+            i2c.read(sensorAddress, &msb, 1); // receive high byte (full degrees)
+            i2c.read(sensorAddress, &lsb, 1); // receive low byte (fraction degrees)
+            
+            temperature = ((msb) << 4);  // MSB
+            temperature |= (lsb >> 4);   // LSB
+
+            temp_msg.data = temperature*0.0625;
+            pub_temp.publish(&temp_msg);
+
+
+            publisher_timer = t.read_ms() + 1000;
+        }
+
+        nh.spinOnce();
+    }
+}
+
+#endif
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