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/*
* Author: Rafael da Mata Neri <rafael.neri@gmail.com>
* Copyright (c) 2015 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#pragma once
#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <mraa/gpio.h>
namespace upm {
/**
* @brief HX711 24-bit ADC library
* @defgroup hx711 libupm-hx711
* @ingroup generic gpio electric
*/
/**
* @library hx711
* @sensor hx711
* @comname HX711 Analog-to-Digital Converter
* @type electric
* @man generic
* @web http://www.dfrobot.com/image/data/SEN0160/hx711_english.pdf
* @con gpio
*
* @brief API for the HX711 Analog-to-Digital Converter
*
* HX711 is a precision 24-bit analog-to-digital converter (ADC)
* designed for weight scales and industrial control applications to
* interface directly with a bridge sensor. This module was tested on
* the Intel(R) Galileo Gen 2 board.
*
* @image html hx711.jpeg
* @snippet hx711.cxx Interesting
*/
class HX711 {
public:
/**
* HX711 constructor
*
* @param data Defines the data pin
* @param sck Defines the clock pin
* @param gain Defines the gain factor
* Valid values are 128 or 64 for channel A; channel B works with a 32-gain factor only
*/
HX711(uint8_t data, uint8_t sck, uint8_t gain = 128);
/**
* HX711 destructor
*/
~HX711();
/**
* Waits for the chip to be ready and returns a reading
*
* @return Raw ADC reading
*/
unsigned long read();
/**
* Sets 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
* factor depending on the parameter; the channel is also set to either A or B
* @param gain Defines the gain factor
*/
void setGain(uint8_t gain = 128);
/**
* Returns an average reading
* @param times Defines how many reading to do
* @return Average reading
*/
unsigned long readAverage(uint8_t times = 10);
/**
* Returns (readAverage() - OFFSET)
* @param times Defines how many readings to do
* @return Current value without the tare weight
*/
double getValue(uint8_t times = 10);
/**
* Returns getValue() divided by SCALE
* @param times Defines how many readings to do
* @return Raw value divided by a value obtained via calibration
*/
float getUnits(uint8_t times = 1);
/**
* Sets the OFFSET value for the tare weight
* @param times Defines how many times to read the tare value
*/
void tare(uint8_t times = 10);
/**
* Sets the SCALE value
* This value is used to convert the raw data to human-readable data (measurement units)
* @param scale Value obtained via calibration
*/
void setScale(float scale = 1.f);
private:
mraa_gpio_context m_sckPinCtx; // Power Down and Serial Clock Input Pin
mraa_gpio_context m_dataPinCtx; // Serial Data Output Pin
uint8_t GAIN; // amplification factor
unsigned long OFFSET; // used for tare weight
float SCALE; // used to return weight in grams, kg, ounces, whatever
/**
* Sets the OFFSET value
* This value is subtracted from the actual reading (tare weight)
* @param scale Value obtained via calibration
*/
void setOffset(long offset = 0);
};
}
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