Revision 0:52c805a049c4, committed 2016-02-21

Comitter:

gert_lauritsen

Date:

Sun Feb 21 11:01:00 2016 +0000

Commit message:

A lib for hx711 SG sensor

Changed in this revision

diff -r 000000000000 -r 52c805a049c4 Hx711.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Hx711.cpp	Sun Feb 21 11:01:00 2016 +0000
@@ -0,0 +1,102 @@
+#include "Hx711.h"
+
+HX711::HX711(PinName pin_dout, PinName pin_slk): _pin_dout(pin_dout), _pin_slk(pin_slk)
+{
+    _pin_slk = 1;
+    wait_ms(100);
+    _pin_slk = 0;
+    
+    set_gain(128);
+}
+
+HX711::~HX711()
+{
+
+}
+
+
+void HX711::set_gain(char gain)
+{
+    switch (gain) {
+        case 128:       // channel A, gain factor 128
+            GAIN = 1;
+            break;
+        case 64:        // channel A, gain factor 64
+            GAIN = 3;
+            break;
+        case 32:        // channel B, gain factor 32
+            GAIN = 2;
+            break;
+    }
+    _pin_slk = 0;
+    read();
+}
+
+long HX711::read()
+{
+    long value = 0;
+
+    while (_pin_dout)
+        ;
+
+    for (int i=0;i<24;i++)
+    { 
+        _pin_slk = 1;
+        value=value<<1; 
+        _pin_slk = 0;
+        if(_pin_dout) value++; 
+    } 
+
+    _pin_slk = 1;
+    _pin_slk = 0;
+
+    value=value^0x800000;
+
+    return value;
+}
+
+long HX711::read_average(char times)
+{
+    long sum = 0;
+    for (char i = 0; i < times; i++) {
+        sum += read();
+    }
+    return sum / times;
+}
+
+double HX711::get_value(char times)
+{
+    return read_average(times) - OFFSET;
+}
+
+float HX711::get_units(char times)
+{
+    return get_value(times) / SCALE;
+}
+
+void HX711::tare(char times)
+{
+    double sum = read_average(times);
+    set_offset(sum);
+}
+
+void HX711::set_scale(float scale)
+{
+    SCALE = scale;
+}
+
+void HX711::set_offset(long offset)
+{
+    OFFSET = offset;
+}
+
+void HX711::power_down()
+{
+  _pin_slk = 0;
+  _pin_slk = 1;
+}
+
+void HX711::power_up()
+{
+  _pin_slk = 0;
+}
\ No newline at end of file

diff -r 000000000000 -r 52c805a049c4 Hx711.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Hx711.h	Sun Feb 21 11:01:00 2016 +0000
@@ -0,0 +1,62 @@
+#ifndef HX711_h
+#define HX711_h
+//Translatet module from arduino to mbed https://codebender.cc/library/HX711#HX711.h
+
+#include "mbed.h"
+
+class HX711
+{
+    private:
+        DigitalOut _pin_slk;    // Power Down and Serial Clock Input Pin
+        DigitalIn _pin_dout;      // Serial Data Output Pin
+        char GAIN;      // amplification factor
+        long OFFSET;    // used for tare weight
+        float SCALE;    // used to return weight in grams, kg, ounces, whatever
+    public:
+        // define clock and data pin, channel, and gain factor
+        // channel selection is made by passing the appropriate gain: 128 or 64 for channel A, 32 for channel B
+        // gain: 128 or 64 for channel A; channel B works with 32 gain factor only
+        HX711(PinName pin_dout, PinName pin_slk);
+
+        virtual ~HX711();
+
+        // check if HX711 is ready
+        // from the datasheet: When output data is not ready for retrieval, digital output pin DOUT is high. Serial clock
+        // input PD_SCK should be low. When DOUT goes to low, it indicates data is ready for retrieval.
+
+
+        // set the gain factor; takes effect only after a call to read()
+        // channel A can be set for a 128 or 64 gain; channel B has a fixed 32 gain
+        // depending on the parameter, the channel is also set to either A or B
+        void set_gain(char gain = 128);
+
+        // waits for the chip to be ready and returns a reading
+        long read();
+
+        // returns an average reading; times = how many times to read
+        long read_average(char times = 10);
+
+        // returns (read_average() - OFFSET), that is the current value without the tare weight; times = how many readings to do
+        double get_value(char times = 1);
+
+        // returns get_value() divided by SCALE, that is the raw value divided by a value obtained via calibration
+        // times = how many readings to do
+        float get_units(char times = 1);
+
+        // set the OFFSET value for tare weight; times = how many times to read the tare value
+        void tare(char times = 10);
+
+        // set the SCALE value; this value is used to convert the raw data to "human readable" data (measure units)
+        void set_scale(float scale = 1.f);
+
+        // set OFFSET, the value that's subtracted from the actual reading (tare weight)
+        void set_offset(long offset = 0);
+
+        // puts the chip into power down mode
+        void power_down();
+
+        // wakes up the chip after power down mode
+        void power_up();
+};
+
+#endif /* HX711_h */
\ No newline at end of file