Revision 1:392a3fb6d177, committed 2021-09-03

Comitter:

CCastrop1012

Date:

Fri Sep 03 04:51:59 2021 +0000

Parent:

0:5d67331a6e7e

Commit message:

Lectura de una celda de Carga.

Changed in this revision

diff -r 5d67331a6e7e -r 392a3fb6d177 HX711.lib
--- a/HX711.lib	Fri May 05 20:16:31 2017 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-http://developer.mbed.org/users/laskowsk/code/HX711/#716e1cbdac61

diff -r 5d67331a6e7e -r 392a3fb6d177 Hx711.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Hx711.cpp	Fri Sep 03 04:51:59 2021 +0000
@@ -0,0 +1,77 @@
+#include "mbed.h"
+#include "Hx711.h"
+
+void Hx711::set_gain(uint8_t 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;
+    }
+
+    sck_.write(LOW);
+    read();
+}
+
+uint32_t Hx711::readRaw() {
+    // wait for the chip to become ready
+    // TODO: this is not ideal; the programm will hang if the chip never
+    // becomes ready...
+    while (!is_ready());
+
+    uint32_t value = 0;
+    uint8_t data[3] = { 0 };
+    uint8_t filler = 0x00;
+
+    // pulse the clock pin 24 times to read the data
+    data[2] = shiftInMsbFirst();
+    data[1] = shiftInMsbFirst();
+    data[0] = shiftInMsbFirst();
+
+    // set the channel and the gain factor for the next reading using the clock pin
+    for (unsigned int i = 0; i < gain_; i++) {
+        sck_.write(HIGH);
+        sck_.write(LOW);
+    }
+
+    // Datasheet indicates the value is returned as a two's complement value
+    // Flip all the bits
+    data[2] = ~data[2];
+    data[1] = ~data[1];
+    data[0] = ~data[0];
+
+    // Replicate the most significant bit to pad out a 32-bit signed integer
+    if ( data[2] & 0x80 ) {
+        filler = 0xFF;
+    } else if ((0x7F == data[2]) && (0xFF == data[1]) && (0xFF == data[0])) {
+        filler = 0xFF;
+    } else {
+        filler = 0x00;
+    }
+
+    // Construct a 32-bit signed integer
+    value = ( static_cast<uint32_t>(filler)  << 24
+            | static_cast<uint32_t>(data[2]) << 16
+            | static_cast<uint32_t>(data[1]) << 8
+            | static_cast<uint32_t>(data[0]) );
+
+    // ... and add 1
+    return static_cast<int>(++value);
+}
+
+
+uint8_t Hx711::shiftInMsbFirst() {
+    uint8_t value = 0;
+
+    for (uint8_t i = 0; i < 8; ++i) {
+        sck_.write(HIGH);
+        value |= dt_.read() << (7 - i);
+        sck_.write(LOW);
+    }
+    return value;
+}

diff -r 5d67331a6e7e -r 392a3fb6d177 Hx711.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Hx711.h	Fri Sep 03 04:51:59 2021 +0000
@@ -0,0 +1,166 @@
+#ifndef _HX711_H_
+#define _HX711_H_
+
+/**
+ * Class for communication with the HX711 24-Bit Analog-to-Digital 
+ * Converter (ADC) for Weigh Scales by AVIA Semiconductor.
+ * This library is a port of the Arduino library at 
+ * https://github.com/bogde/HX711
+ * It works with the FRDM K22F.
+ */
+class Hx711 {
+
+public:
+
+    /**
+     * Create an Hx711 ADC object
+     * @param pin_sck PinName of the clock pin (digital output)
+     * @param pin_dt PinName of the data pin (digital input)
+     * @param offset offset for sensor values
+     * @param scale scale factor to obtain real values
+     * @param gain channel selection is made by passing the appropriate gain: 
+     *      128 or 64 for channel A, 32 for channel B
+     */
+    Hx711(PinName pin_sck, PinName pin_dt, float offset, float scale, uint8_t gain = 128) :
+        sck_(pin_sck),
+        dt_(pin_dt) {
+        set_offset(offset);
+        set_scale(scale);
+        set_gain(gain);
+    }
+    
+    /**
+     * Create an Hx711 ADC object with zero offset and unit scaling
+     * @param pin_sck PinName of the clock pin (digital output)
+     * @param pin_dt PinName of the data pin (digital input)
+     * @param gain channel selection is made by passing the appropriate gain: 
+     *      128 or 64 for channel A, 32 for channel B
+     * TODO: constructor overloading is not allowed?
+     */
+    Hx711(PinName pin_sck, PinName pin_dt, uint8_t gain = 128) :
+        sck_(pin_sck),
+        dt_(pin_dt) {
+        set_offset(0);
+        set_scale(1.0f);
+        set_gain(gain);
+    }
+
+    /**
+     * Check if the sensor 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.
+     * @return true if dt_.read() == LOW
+     * TODO: this is not ideal; the programm will hang if the chip never
+     * becomes ready...
+     */
+    bool is_ready() {
+        return dt_.read() == LOW;
+    }
+    
+    /**
+     * Waits for the chip to be ready and returns a raw int reading
+     * @return int sensor output value
+     */
+    uint32_t readRaw();
+    
+    /**
+     * Obtain offset and scaled sensor output; i.e. a real value
+     * @return float
+     */
+    float read() {
+        return convert_to_real(readRaw());
+    }
+    
+    /**
+     * Convert integer value from chip to offset and scaled real value
+     * @param val integer value
+     * @return (val - get_offset()) * get_scale()
+     */
+    float convert_to_real(int val) {
+        return ((float)(val - get_offset())) * get_scale();
+    }
+    
+    /**
+     * Puts the chip into power down mode
+     */
+    void power_down() {
+        sck_.write(LOW);
+        sck_.write(HIGH);
+    }
+
+    /**
+     * Wakes up the chip after power down mode
+     */
+    void power_up() {
+        sck_.write(LOW);
+    }
+
+    /**
+     * 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
+     * Ensures that gain_ = 128, 64 or 32
+     * @param gain 128, 64 or 32
+     */
+    void set_gain(uint8_t gain = 128);
+    
+    /**
+     * Obtain current gain
+     * @return gain_
+     */
+    uint8_t get_gain() {
+        return gain_;
+    }
+
+    /**
+     * Set the scale factor
+     * @param scale desired scale
+     */
+    void set_scale(float scale = 1.0f) { 
+        scale_ = scale; 
+    };
+
+    /**
+     * Get sensor scale factor
+     * @return scale_
+     */
+    float get_scale() { 
+        return scale_; 
+    }
+
+    /**
+     * Set the sensor offset
+     * @param offset the desired offset
+     */
+    void set_offset(float offset = 0.0) { 
+        offset_ = offset; 
+    }
+
+    /**
+     * Get current sensor offset
+     * @return offset_
+     */
+    float get_offset() { return offset_; }
+    
+
+private:
+
+    static const uint8_t LOW      = 0; // digital low
+    static const uint8_t HIGH     = 1; // digital high
+
+    DigitalOut sck_;    // clock line
+    DigitalIn dt_;      // data line 
+
+    uint8_t gain_;      // amplification factor at chip
+    float offset_;        // offset chip value
+    float scale_;       // scale output after offset
+
+    /**
+     * Port of the Arduino shiftIn function; shifts a byte one bit at a time
+     * @return incoming but
+     */
+    uint8_t shiftInMsbFirst();
+};
+
+#endif
\ No newline at end of file

diff -r 5d67331a6e7e -r 392a3fb6d177 TextLCD.lib
--- a/TextLCD.lib	Fri May 05 20:16:31 2017 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,1 +0,0 @@
-http://mbed.org/users/simon/code/TextLCD/#308d188a2d3a

diff -r 5d67331a6e7e -r 392a3fb6d177 main.cpp
--- a/main.cpp	Fri May 05 20:16:31 2017 +0000
+++ b/main.cpp	Fri Sep 03 04:51:59 2021 +0000
@@ -1,30 +1,65 @@
 #include "mbed.h"
-#include "HX711.h"
-#include "TextLCD.h" 
+#include "Hx711.h"
+
+#define n_muestras 10
 
-DigitalOut led(LED_BLUE);
-HX711 scale(PTC9, PTC8);
+DigitalOut led(LED1);
+
+Hx711 LoadCeld(A1, A0, 1, 1.0);
 
 Serial rs232(USBTX, USBRX);    // USB Serial Terminal
-TextLCD lcd(PTE20,PTE21,PTE22,PTE23,PTE29,PTE30, TextLCD::LCD16x2); // Rs, E, d4, d5, d6, d7 
+
+
+
+
 
+
+float escala = 0.0;
+float offset; 
 float calibration_factor = 1000; //Ajustar este valor para calibrar el peso exacto
-int averageSamples = 100;
+int averageSamples = 300;
 
 int main(void)
 {
      
-    scale.setScale(0);
-    scale.tare(); //Reset the scale to 0
+     
+    for(int i = 0; i < n_muestras; i++ )
+    {
+        while(!LoadCeld.is_ready());
+        
+        offset = ( offset + LoadCeld.readRaw());
+
+    }
     
-    long zero_factor = scale.averageValue(averageSamples); // Saca promedio de varias lecturas para estabilizar la medida
+    offset = (offset / n_muestras);
+    LoadCeld.set_offset(offset);
+    LoadCeld.set_scale(1.0);
+    rs232.printf("Offset: %.2f \n", offset);
+    rs232.printf("Offset: %.2f \n", LoadCeld.get_offset());
+    offset = 0.0;
+    
+    //scale.tare(); //Reset the scale to 0
+    
+    //long zero_factor = scale.averageValue(averageSamples); // Saca promedio de varias lecturas para estabilizar la medida
      
     while (true) {
-        scale.setScale(calibration_factor); 
-        float weight = scale.getGram();
-        rs232.printf("Peso: %.2f\n", weight);
-        lcd.locate(0,0);
-        lcd.printf("Peso: %.2f Grms", weight);
+        
+        
+        for(int i = 0; i < n_muestras; i++ )
+        {
+            while(!LoadCeld.is_ready());
+            
+            escala = ( escala + LoadCeld.read());
+
+        }
+        escala = (escala / n_muestras);
+        rs232.printf("Peso: %.2f \n", escala); 
+        escala = 0.0;
+        //scale.setScale(calibration_factor); 
+        //float weight = scale.getGram();
+        //rs232.printf("Peso: %.2f\n", weight);
+        //lcd.locate(0,0);
+        //lcd.printf("Peso: %.2f Grms", weight);
         led = !led; // toggle led
         wait(0.2f);
     }