Firmware

youdllo, Rania Ghellal, Mohamed LY Mohamed LY

Published January 20, 2020 © GPL3+

Agrotech: Monitor Your Greenhouse!

In this project, you will be able to display the temperature, humidity of soil and air, luminosity and spectral quality from a dashboard.

IntermediateFull instructions provided3 days1,702

Things used in this project

Hardware components

ST STM32L4, STM32F7 Nucleo 144 STM32F7

DHT22 Temperature Sensor

DFRobot Gravity: TCS34725 RGB Color Sensor For Arduino

DFRobot Gravity: Analog Soil Moisture Sensor For Arduino

Adafruit Waterproof DS18B20 Digital temperature sensor

Li-Ion Battery 100mAh

Solar Panel, 2.5 W

Hand tools and fabrication machines

on line mbed compiler

kicad: shematic editor and pcb layout

SigFox

Ubidots

Story

Firmware

We want the values captured by our sensors to be displayed in a dashboard with an interval of about 10 minutes.

Sensors code :

We have 4 sensors :

DS18B20 used to measure soil temperature

used library : DS1820

Gravity SEN0193 used to measure soil moisture

No library needed
click on this tutorial to calibrate the sensor

DHT22 used to measure air humidity and air temperature

used library : DHT

TCS34725 used to measure light spectrum and brightness

used library : TCS34725

Here is the mbed code link : https://os.mbed.com/users/ran_ghe/code/AgroTech/

Sending to Sigfox

We are sending 12 bytes every 10 minutes. With these sensors, 12 bytes are enough to send all values at the same time :

brightness = 3 bytes
light spectrum = 1 byte per primary color (RGB)
temperature = 2 bytes for air temperature and 2 bytes for soil temperature
humidity = 1 byte for air humidity and 1 byte for soil humidity

In the Sigfox backend, we can see our values but as you can see it’s not very readable. That’s why we will have to do a callback to a dashboard.

Callback to Ubidots

Now we will configure a callback to receive the rights values in our dashboard (here we choose ubidots because it’s very simple to configure)

The custom payload config is directly dependant on how we send values to Sigfox :

luminosite::uint:24  red::uint:8 green::uint:8 blue::uint:8  tempSol::uint:16 humSol::uint:8 tempAir::uint:16 humAir::uint:8

This means our first 24 bits are dedicated to the brightness, the next 8 bits are for the red value etc...

Lower consumption

Now, we want lower the consumption to make it more autonomous in terms of energy supply. As we use our microcontroller only one time per 10 minutes, we can use the deep sleep mode for 90% of the time ! For that, we use the WakeUp library.

Code

Agrotech

#include "mbed.h"
#include "DS1820.h"
#include "DHT.h"
#include "TSL2561_I2C.h"
#include "Adafruit_TCS34725.h"
#include "WakeUp.h"



Serial wisol(D1, D0); // tx, rx

//debug
Serial pc(USBTX, USBRX);

//tempAir et humAir
DHT dht(D9, 22);


//RGB + luminosite
I2C i2c(PB_7, PB_6);
Adafruit_TCS34725 tcs = Adafruit_TCS34725(&i2c, TCS34725_INTEGRATIONTIME_50MS, TCS34725_GAIN_4X);

//tempSol 
DS1820 temp_sol(A4);

//humSol
AnalogIn   ain(A3);

int main(){
    
    //WakeUp::calibrate();   
    
        
    //DHT22
    int data;
    float tempAir, humAir;
    
    //humiditeSol
    int hum_sol;
    
    //luminosite
    float lux;
    
    //temp_sol
    if(temp_sol.unassignedProbe(A4))
    {
        pc.printf("error temperature_sol");
    }
    
    //capteur RGB/luminosite
    if(!tcs.begin())
    {
        pc.printf("No TCS34725 found ... check your connections");
    }
    
    while(1){
        //Capteur air
        data = dht.readData();
        humAir = dht.ReadHumidity();
        tempAir = dht.ReadTemperature(CELCIUS);
        pc.printf("tempAir = %1.f, humAir = %1.f\n", tempAir, humAir);
        
        
        //capteur humidite sol
        hum_sol = (int)(((0.78 - ain.read())*100)/0.38);
        pc.printf ("humSol =  %d%\n", hum_sol);
         
        //Capteur temperature sol
        temp_sol.convertTemperature(true, DS1820::all_devices);
        pc.printf("tempSol : %.1f\n", temp_sol.temperature());
        
        
        
        ///////////////
        //////RGB//////
        ///////////////
        
        uint16_t clear, red, green, blue;
        tcs.setInterrupt(false);      // turn on LED
        tcs.getRawData(&red, &green, &blue, &clear);
        tcs.setInterrupt(true);  // turn off LED
        //pc.printf("clear = %d, red = %d, green = %d, blue = %d\r\n", clear, red, green, blue);
        
        //get hexa value
        uint32_t sum = clear;
        float r, g, b;
        r = red; r /= sum;
        g = green; g /= sum;
        b = blue; b /= sum;
        r *= 256; g *= 256; b *= 256;
        pc.printf("clear = %d, red = %d, green = %d, blue = %d\r\n\n", clear, (int)r, (int)g, (int)b);
        
        
        
        
        //luminosite
        lux = (int)tcs.calculateLux(red,green,blue);
        pc.printf("lux = %d\n", (int)lux);
        
        
        wisol.printf("AT$SF=%06X%02X%02X%02X%04X%02X%04X%02X\r\n", (int)lux, (int)r, (int)g, (int)b, (int)(10 * temp_sol.temperature()), (int)(hum_sol), (int)(10 * tempAir), (int)(humAir));
                
        
        //lux : 3 octets
        //r, g, b : 1 octet
        //tempSol, tempAir : 2 octets
        //humSol, humAir : 1 octet
        
        wait(10);
        
        //Set wakeup time for 600 seconds = 10min
        WakeUp::set_ms(600000);
        deepsleep();
        wait(1);
        
    }
}

Agrotech: Monitor Your Greenhouse!