Published November 13, 2021 © CC BY-NC-SA

1-Wire Soil Moisture Sensor demo Arduino/ESP32/Raspberry PI

Read 1-Wire soil moisture sensor by ONLY ONE I/O , including soil moisture, temperature, and EC (Conductivity).

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1-Wire Soil Moisture Sensor demo Arduino/ESP32/Raspberry PI

Things used in this project

Hardware components

MT05S - Soil Moisture/Temperature/EC Sensor

Arduino UNO R3

Espressif ESP32S

Raspberry Pi 3 Model B

Hand tools and fabrication machines

Arduino IDE

OneWire Library by Paul Stoffregen

Story

This project shows how to use 1-Wire Soil Moisture Sensor, Especially on Arduino/ESP32 and Raspberry Pi, using ONLY ONE I/O pin. For more detail on 1-Wire Soil Moisture Sensor, please refer to link below:

1-Wire Soil Moisture Sensor with Temperature and EC (Conductivity) Measurement.

1. Brief on 1-Wire Soil Moisture Sensor

MT05S is 1-Wire soil moisture sensor, measuring soil moisture content, temperature and EC(Conductivity) according to the order information. It sealed with resin packaged plastic body with sensing rods which can be insert directly into the soil with long time stability. Sensor with relatively small size and can be used for pot culture and Seedling tray. The sensor is applicable for science research, irrigation, greenhouse, smart agriculture etc.

■ Integrated with Soil Moisture, temperature or with EC (Conductivity) measurement

■ 1-Wire bus interface, Operation compatible with DS18B20

■ Directly connect with MCU, Arduino, Raspberry PI or other modules by only one I/O pin, No other signal conversion board required, Software library for DS18B20 can be reused to read/write the sensor

■ ROMCODE can be set by extension function command for easily addressing

■ Power Supply 2.7-12V DC, Low Quiescent current Max. 30uA

■ Low salinity sensitivity and Minimal soil disturbance

■ Water proof to IP68 ratings and can be directly buried into soil

■ High accuracy with excellent stability

■ Reverse power protection and Built-in TVS/ESD protection

2. Connect Sensor to Arduino/ESP32/Raspberry Pi

1 / 3 • Wiring Diagram - Arduino/ESP32/Raspberry Pi

1 / 3 • Wiring Connection- Arduino/ESP32/Raspberry Pi

3. Arduino IDE: Install Library and Run Demo

Install OneWire support library inMenu>Tools>Manage Libaries, search OneWire library and then install.

Download Source Code HERE and then Run Demo

Code

#include <OneWire.h>

#define TEST_MT05S_ONEWIRE_CONVERT_T            1

// Define a 1-Wire signal pin (a 2.0K~5.1K pull-up resistor is necessary)
// Change according to your wiring and connection.
OneWire  ds(2);  

void setup(void) {
  Serial.begin(9600);
}

void loop(void) {
  Serial.println("//-------------------------");
  Serial.println("// Start Testing MT05S     ");
  Serial.println("//-------------------------");
  uint8_t i;

#ifdef TEST_MT05S_ONEWIRE_CONVERT_T
  //--------------------------------------------
  // Tested - Convert T and Read Scratchpad
  // Attention: 
  //--------------------------------------------
  Serial.print("Test Function Command- Convert T [0x44]  & Read Scratchpad [0xBE]: \n");
  byte scratchpad[9];

  Serial.print("Convert T [0x44]: ");
  ds.reset();//Send RESET
  ds.skip();//Send ROM Command-Skip ROM
  ds.write(0x44);//Send Function command- convert T

  //Wait conversion done (Whether to pull down the DQ line during operation can be configured in scratchpad CONFIG0-Bit3- SensorPowerMode)
  while(ds.read_bit() == 0)
  {
    delay(10);
    Serial.print(".");
  }
  Serial.print("Conversion Done\n");

  Serial.print("Read Scratchpad [0xBE]: ");
  ds.reset();//Send RESET
  ds.skip();//Send ROM Command-Skip ROM
  ds.write(0xBE);//Send Function command- Read Scratchpad
  for (int i = 0; i < 9; i++) {// we need 9 bytes
    scratchpad[i] = ds.read();
  }
  for (int i = 0; i < 9; i++) {// we need 9 bytes
    Serial.print(scratchpad[i],HEX);
    Serial.print(" ");
  }
  Serial.print(" CrcCalculated=");
  Serial.print(OneWire::crc8(scratchpad, 8),HEX);
  Serial.println();

  if(OneWire::crc8(scratchpad, 8) == scratchpad[8])
  {
    int16_t temperature = makeWord(scratchpad[0],scratchpad[1]);
    int16_t moisture = makeWord(scratchpad[2],scratchpad[3]);
    int16_t conductivity = makeWord(scratchpad[4],scratchpad[5]);
    Serial.print("TEMP(C) = "); Serial.print(temperature/100.00);
    Serial.print("  MOISTURE(%) = "); Serial.print(moisture/100.00);
    Serial.print("  CONDUCTIVITY(ms/cm) = "); Serial.print(conductivity/1000.00);
    Serial.print("  CONFIG0 = "); Serial.print(scratchpad[6],HEX);
    Serial.print("  CONFIG1 = "); Serial.print(scratchpad[7],HEX);
    Serial.print("  CRC8 = "); Serial.print(scratchpad[8],HEX);
  }
  else
  {
    Serial.print("CRC ERROR!");
  }
  Serial.print("\n\n");
  
  delay(1000);
#endif
}

#!/usr/bin/python3
import os,time

ROMCODE='28-060504030201'
device_file ='/sys/bus/w1/devices/'+ROMCODE+'/w1_slave'
print("//----------------------------------------------------------------");
print("// Start Testing MT05S");
print("// Rom Code= " + ROMCODE);
print("// Change ROM CODE FOR YOUR SENSOR !!!!!!");
print("//----------------------------------------------------------------");

def read_raw():
    f = open(device_file,'r')
    lines = f.readlines()
    f.close()
    return lines

def read_mt05s():
    lines = read_raw()
    while lines[0].strip()[-3:] != 'YES':
        print('Incorrect Data')
        time.sleep(0.2)
        lines = read_raw()
    byteList = lines[1].rsplit((' '))
    if len(byteList) >9 :
        soilTempHi8=int(byteList[0], 16)
        soilTempLo8=int(byteList[1], 16)
        soilTemp = soilTempHi8*256+soilTempLo8

        soilMoistureHi8=int(byteList[2], 16)
        soilMoistureLo8=int(byteList[3], 16)
        soilMoisture = soilMoistureHi8*256+soilMoistureLo8

        soilECHi8=int(byteList[4], 16)
        soilECLo8=int(byteList[5], 16)
        soilEC = soilECHi8*256+soilECLo8
    return [ soilTemp, soilMoisture, soilEC  ]

while True:
    values = read_mt05s()
    print('Soil Temp(C)= %.2f  Moisture(%%)= %.2f  EC(ms/cm)= %.3f' %(values[0]/100.0,  values[1]/100.0,  values[2]/1000.0))
    time.sleep(1)