Chirp is a great little soil moisture sensor. This is a library for the Chirp soil moisture sensor. It supports reading Capacitance (soil moisture) and soil temperature. You can get Chirp on Tindie https://www.tindie.com/products/miceuz/i2c-soil-moisture-sensor/ And read documentation on github https://www.tindie.com/products/miceuz/i2c-soil-moisture-sensor/

Dependents:   Test_Chirp

Revision:
0:6164b94deb27
Child:
1:faff11456df9
diff -r 000000000000 -r 6164b94deb27 Chirp.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Chirp.cpp	Thu Jan 12 22:01:43 2017 +0000
@@ -0,0 +1,48 @@
+#include "mbed.h"
+#include "Chirp.h"
+
+//Chirp Docs are at https://github.com/Miceuz/i2c-moisture-sensor and https://www.tindie.com/products/miceuz/i2c-soil-moisture-sensor/
+
+Chirp::Chirp(PinName sda, PinName scl, char slave_adr)
+    :i2c_p(new I2C(sda, scl)), i2c(*i2c_p), address(slave_adr)
+{
+
+}
+
+float Chirp::getCapacitance(){
+    short capacitance = 0;
+    char i2cData[2]= {0}; 
+    
+    char dataReg = 0; //Capacitance is stored in 2 bytes at address 0
+    i2c.write(address, &dataReg, 1); 
+    int success = i2c.read(address, i2cData, 2);
+    
+    if(success != 0)
+        return -1000000; 
+    else
+    {
+        //I2C bytes are in different byte order, write into short bytes 0 and 1 in reverse order!
+        *((char*)&capacitance) = i2cData[1];
+        *(((char*)(&capacitance)) + 1) = i2cData[0];
+        return capacitance;
+    }
+}
+
+float Chirp::getTemperature(){
+    short temperature = 0;
+    char i2cData[2]= {0}; 
+    
+    char dataReg = 5; //Temperature is stored in 2 bytes at address 5
+    i2c.write(address, &dataReg, 1); 
+    int success = i2c.read(address, i2cData, 2);
+    
+    if(success != 0)
+        return -1000000; 
+    else
+    {
+        *((char*)&temperature) = i2cData[1];
+        *(((char*)(&temperature)) + 1) = i2cData[0];
+        return (float) temperature / 10.0;
+    }
+}
+    
\ No newline at end of file