VictorienClément Martin
Published

BeeWatched, the Connected Beehive Monitoring Box

BeeWatched will help you to check humidity and temperature of your beehive to ensure that it is in good health.

IntermediateFull instructions providedOver 2 days516

Things used in this project

Hardware components

STM32 Nucleo STM32 L432KC
×1
DHT22 Temperature Sensor
DHT22 Temperature Sensor
×1
Sigfox BRKWS01 + Antenne
×1
Breadboard (generic)
Breadboard (generic)
×1
3.7 V LiPo Battery
×1
Adafruit TPL5110 Power Timer Breakout Board
×1
Pololu 3.3V Step-Up/Step-Down Voltage Regulator S7V8F3
×1
Maxim Integrated MAX1555EZK+T - Chargeur de batterie, Batterie 1 cellule Li-Ion, Entrée 7 V, Charge 6 V / 280 mA, SOT-23-5
×1

Software apps and online services

Arm Mbed OS Mbed
Altium Designer
SolidWorks
Backend Sigfox

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)
Bantam Tools Desktop PCB Milling Machine
Bantam Tools Desktop PCB Milling Machine
3D Printer (generic)
3D Printer (generic)

Story

Read more

Custom parts and enclosures

BeeWatched Enclosure

3D printing

Schematics

Schematic

Code

mbed_dht.h

C/C++
DHT22 Library
/* 
 *  DHT Library for  Digital-output Humidity and Temperature sensors 
 *  
 *  Works with DHT11, DHT21, DHT22
 *             SEN11301P,  Grove - Temperature&Humidity Sensor     (Seeed Studio)
 *             SEN51035P,  Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
 *             AM2302   ,  temperature-humidity sensor    
 *             RHT01,RHT02, RHT03    ,  Humidity and Temperature Sensor         (Sparkfun)
 *
 *  Copyright (C) Wim De Roeve
 *                based on DHT22 sensor library by HO WING KIT
 *                Arduino DHT11 library
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documnetation 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
 * furished 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 OR 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.
 */
 
#ifndef MBED_DHT_H
#define MBED_DHT_H
 
#include "mbed.h"
 
enum eType{
        DHT11     = 11,
        SEN11301P = 11,
        RHT01     = 11,
        DHT22     = 22,
        AM2302    = 22,
        SEN51035P = 22,
        RHT02     = 22,
        RHT03     = 22
    } ;
 
enum eError {
    ERROR_NONE = 0,
    BUS_BUSY =1,
    ERROR_NOT_PRESENT =2 ,
    ERROR_ACK_TOO_LONG =3 ,
    ERROR_SYNC_TIMEOUT = 4,
    ERROR_DATA_TIMEOUT =5 ,
    ERROR_CHECKSUM = 6,
    ERROR_NO_PATIENCE =7
} ;
 
typedef enum {
    CELCIUS =0 ,
    FARENHEIT =1,
    KELVIN=2
} eScale;
 
 
class DHT {
 
public:
 
    DHT(PinName pin,int DHTtype);
    ~DHT();
    int readData(void);
    float ReadHumidity(void);
    float ReadTemperature(eScale Scale);
    float CalcdewPoint(float celsius, float humidity);
    float CalcdewPointFast(float celsius, float humidity);
 
private:
    time_t  _lastReadTime;
    float _lastTemperature;
    float _lastHumidity;
    PinName _pin;
    bool _firsttime;
    int _DHTtype;
    int DHT_data[6];
    float CalcTemperature();
    float CalcHumidity();
    float ConvertCelciustoFarenheit(float);
    float ConvertCelciustoKelvin(float);
 
};
 
#endif

DHT22 program

C/C++
/*
 *  DHT Library for  Digital-output Humidity and Temperature sensors
 *
 *  Works with DHT11, DHT22
 *             SEN11301P,  Grove - Temperature&Humidity Sensor     (Seeed Studio)
 *             SEN51035P,  Grove - Temperature&Humidity Sensor Pro (Seeed Studio)
 *             AM2302   ,  temperature-humidity sensor
 *             HM2303   ,  Digital-output humidity and temperature sensor
 *
 *  Copyright (C) Wim De Roeve
 *                based on DHT22 sensor library by HO WING KIT
 *                Arduino DHT11 library 
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documnetation 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
 * furished 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 OR 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.
 */
 
#include "mbed_dht.h"
 
#define DHT_DATA_BIT_COUNT 41
 
DHT::DHT(PinName pin,int DHTtype) {
    _pin = pin;
    _DHTtype = DHTtype;
    _firsttime=true;
}
 
DHT::~DHT() {
}
 
int DHT::readData() {
    int i, j, retryCount,b;
    unsigned int bitTimes[DHT_DATA_BIT_COUNT];
 
    eError err = ERROR_NONE;
    time_t currentTime = time(NULL);
 
    DigitalInOut DHT_io(_pin);
 
    for (i = 0; i < DHT_DATA_BIT_COUNT; i++) {
        bitTimes[i] = 0;
    }
 
    if (!_firsttime) {
        if (int(currentTime - _lastReadTime) < 2) {
            err = ERROR_NO_PATIENCE;
            return err;
        }
    } else {
        _firsttime=false;
        _lastReadTime=currentTime;
    }
    retryCount = 0;
 
    do {
        if (retryCount > 125) {
            err = BUS_BUSY;
            return err;
        }
        retryCount ++;
        wait_us(2);
    } while ((DHT_io==0));
 
 
    DHT_io.output();
    DHT_io = 0;
    wait_ms(18);
    DHT_io = 1;
    wait_us(40);
    DHT_io.input();
 
    retryCount = 0;
    do {
        if (retryCount > 40)  {
            err = ERROR_NOT_PRESENT;
            return err;
        }
        retryCount++;
        wait_us(1);
    } while ((DHT_io==1));
 
    if (err != ERROR_NONE) {
        return err;
    }
 
    wait_us(80);
 
    for (i = 0; i < 5; i++) {
        for (j = 0; j < 8; j++) {
 
            retryCount = 0;
            do {
                if (retryCount > 75)  {
                    err = ERROR_DATA_TIMEOUT;
                    return err;
                }
                retryCount++;
                wait_us(1);
            } while (DHT_io == 0);
            wait_us(40);
            bitTimes[i*8+j]=DHT_io;
 
            int count = 0;
            while (DHT_io == 1 && count < 100) {
                wait_us(1);
                count++;
            }
        }
    }
    DHT_io.output();
    DHT_io = 1;
    for (i = 0; i < 5; i++) {
        b=0;
        for (j=0; j<8; j++) {
            if (bitTimes[i*8+j+1] > 0) {
                b |= ( 1 << (7-j));
            }
        }
        DHT_data[i]=b;
    }
 
    if (DHT_data[4] == ((DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3]) & 0xFF)) {
        _lastReadTime = currentTime;
        _lastTemperature=CalcTemperature();
        _lastHumidity=CalcHumidity();
 
    } else {
        err = ERROR_CHECKSUM;
    }
 
    return err;
 
}
 
float DHT::CalcTemperature() {
    int v;
 
    switch (_DHTtype) {
        case DHT11:
            v = DHT_data[2];
            return float(v);
        case DHT22:
            v = DHT_data[2] & 0x7F;
            v *= 256;
            v += DHT_data[3];
            v /= 10;
            if (DHT_data[2] & 0x80)
                v *= -1;
            return float(v);
    }
    return 0;
}
 
float DHT::ReadHumidity() {
    return _lastHumidity;
}
 
float DHT::ConvertCelciustoFarenheit(float celsius) {
    return celsius * 9 / 5 + 32;
}
 
float DHT::ConvertCelciustoKelvin(float celsius) {
    return celsius + 273.15;
}
 
// dewPoint function NOAA
// reference: http://wahiduddin.net/calc/density_algorithms.htm
float DHT::CalcdewPoint(float celsius, float humidity) {
    float A0= 373.15/(273.15 + celsius);
    float SUM = -7.90298 * (A0-1);
    SUM += 5.02808 * log10(A0);
    SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;
    SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;
    SUM += log10(1013.246);
    float VP = pow(10, SUM-3) * humidity;
    float T = log(VP/0.61078);   // temp var
    return (241.88 * T) / (17.558-T);
}
 
// delta max = 0.6544 wrt dewPoint()
// 5x faster than dewPoint()
// reference: http://en.wikipedia.org/wiki/Dew_point
float DHT::CalcdewPointFast(float celsius, float humidity)
{
        float a = 17.271;
        float b = 237.7;
        float temp = (a * celsius) / (b + celsius) + log(humidity/100);
        float Td = (b * temp) / (a - temp);
        return Td;
}
 
float DHT::ReadTemperature(eScale Scale) {
    if (Scale == FARENHEIT)
        return ConvertCelciustoFarenheit(_lastTemperature);
    else if (Scale == KELVIN)
        return ConvertCelciustoKelvin(_lastTemperature);
    else
        return _lastTemperature;
}
 
float DHT::CalcHumidity() {
    int v;
 
    switch (_DHTtype) {
        case DHT11:
            v = DHT_data[0];
            return float(v);
        case DHT22:
            v = DHT_data[0];
            v *= 256;
            v += DHT_data[1];
            v /= 10;
            return float(v);
    }
    return 0;
}

main project code

C/C++
To control sensor and Sigfox
#include "mbed.h"
#include "mbed_dht.h"

DigitalOut myled(LED1);
DigitalOut done(D2);
DHT sensor(D4,DHT22);
Serial pc(SERIAL_TX, SERIAL_RX);
Serial Sigfox (D1, D0);

int main()
{
    int err;
    float temperature;
    float humidite;
    int tAV, hAV;
    //long toSend;
    
    Sigfox.baud(9600);
    
    pc.printf("\r\nProgramme de test DHT");
    pc.printf("\r\n*********************\r\n");
    wait(1);

    while(1)
    {
        myled = 1;
        done = 0;
        err = sensor.readData();
        if (err == 0) {
            temperature = sensor.ReadTemperature(CELCIUS);
            humidite = sensor.ReadHumidity();
            tAV = (int) temperature;
            hAV = (int) humidite;
            //toSend = tAV*10000+hAV; // multiplication de la temperature et ajout de l'humidite pour avoir les premier 4 chiffres pour la temperature et les 4 derniers pour l'humidite
            //Sigfox.printf("AT$SF=101010\n");
            
            Sigfox.printf("AT$SF=%X%X\n", tAV,hAV);
            pc.printf("AT$SF=%04d\n", tAV);
            //Sigfox.printf("AT$SF=%04x\n", hAV);
            pc.printf("AT$SF=%04d\n", hAV);
            //Sigfox.printf("AT$SF=%d%d\n", tAV, hAV);
            //Sigfox.printf("AT$SF=%08X\n", toSend);
            pc.printf("\r\n\r\nTemperature is %d", tAV);
            pc.printf("\r\nHumidity is %d", hAV);
            //pc.printf("\r\nTemperature is %4.2f C", temperature);
            //pc.printf("\r\nHumidity is %4.2f", humidite);
            wait(7);
            done=1;
        } else
            pc.printf("\r\n\r\nErreur %i \r\n", err);
        myled = 0;
        wait(10);
        myled = 1;
        wait(10);
    }
}

Credits

Victorien

Victorien

1 project • 0 followers
Clément Martin

Clément Martin

1 project • 0 followers

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