@Jan-Gatzke I have connected the fork to A0 and A1 of mine arduino nano. Now i have this result:
10.02.2017 12:17:35 Multi Sensor (multi2) SoilMoistPercentageSensor -182 %
10.02.2017 12:12:04 Multi Sensor (multi2) SoilMoistPercentageSensor -455 %
10.02.2017 12:06:33 Multi Sensor (multi2) SoilMoistPercentageSensor -317 %
10.02.2017 12:01:02 Multi Sensor (multi2) SoilMoistPercentageSensor 255 %
10.02.2017 11:55:31 Multi Sensor (multi2) SoilMoistPercentageSensor -547 %
10.02.2017 11:49:26 Multi Sensor (multi2) SoilMoistPercentageSensor 1169 %
10.02.2017 11:43:55 Multi Sensor (multi2) SoilMoistPercentageSensor 40 %
10.02.2017 11:38:24 Multi Sensor (multi2) SoilMoistPercentageSensor -250 %
This is the sketch i use:
/*
* The MySensors Arduino library handles the wireless radio link and protocol
* between your home built sensors/actuators and HA controller of choice.
* The sensors forms a self healing radio network with optional repeaters. Each
* repeater and gateway builds a routing tables in EEPROM which keeps track of the
* network topology allowing messages to be routed to nodes.
*
* Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
* Copyright (C) 2013-2015 Sensnology AB
* Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
*
* Documentation: http://www.mysensors.org
* Support Forum: http://forum.mysensors.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2 as published by the Free Software Foundation.
*
*******************************
*
* DESCRIPTION
*
* Arduino soil moisture based on gypsum sensor/resistive sensor to avoid electric catalyse in soil
* Required to interface the sensor: 2 * 4.7kOhm + 2 * 1N4148
*
* Gypsum sensor and calibration:
* DIY: See http://vanderleevineyard.com/1/category/vinduino/1.html
* Built: Davis / Watermark 200SS
* http://www.cooking-hacks.com/watermark-soil-moisture-sensor?_bksrc=item2item&_bkloc=product
* http://www.irrometer.com/pdf/supportmaterial/sensors/voltage-WM-chart.pdf
* cb (centibar) http://www.irrometer.com/basics.html
* 0-10 Saturated Soil. Occurs for a day or two after irrigation
* 10-20 Soil is adequately wet (except coarse sands which are drying out at this range)
* 30-60 Usual range to irrigate or water (except heavy clay soils).
* 60-100 Usual range to irrigate heavy clay soils
* 100-200 Soil is becoming dangerously dry for maximum production. Proceed with caution.
*
* Connection:
* D6, D7: alternative powering to avoid sensor degradation
* A0, A1: alternative resistance mesuring
*
* Based on:
* "Vinduino" portable soil moisture sensor code V3.00
* Date December 31, 2012
* Reinier van der Lee and Theodore Kaskalis
* www.vanderleevineyard.com
* Contributor: epierre
*/
// Copyright (C) 2015, Reinier van der Lee
// www.vanderleevineyard.com
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Enable debug prints to serial monitor
#define MY_DEBUG
// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69
#include <math.h> // Conversion equation from resistance to %
#include <MySensors.h>
// Setting up format for reading 3 soil sensors
#define NUM_READS 10 // Number of sensor reads for filtering
#define CHILD_ID 0
MyMessage msg(CHILD_ID, V_LEVEL);
unsigned long SLEEP_TIME = 30000; // Sleep time between reads (in milliseconds)
long buffer[NUM_READS];
int index;
/// @brief Structure to be used in percentage and resistance values matrix to be filtered (have to be in pairs)
typedef struct {
int moisture; //!< Moisture
long resistance; //!< Resistance
} values;
const long knownResistor = 4700; // Constant value of known resistor in Ohms
int supplyVoltage; // Measured supply voltage
int sensorVoltage; // Measured sensor voltage
values valueOf[NUM_READS]; // Calculated moisture percentages and resistances to be sorted and filtered
int i; // Simple index variable
void setup()
{
// initialize the digital pins as an output.
// Pin 6,7 is for sensor 1
// initialize the digital pin as an output.
// Pin 6 is sense resistor voltage supply 1
pinMode(6, OUTPUT);
// initialize the digital pin as an output.
// Pin 7 is sense resistor voltage supply 2
pinMode(7, OUTPUT);
}
void presentation()
{
sendSketchInfo("Soil Moisture Sensor Reverse Polarity", "1.0");
present(CHILD_ID, S_MOISTURE);
}
void loop()
{
measure(6,7,1);
Serial.print ("\t");
Serial.println (average());
long read1 = average();
measure(7,6,0);
Serial.print ("\t");
Serial.println (average());
long read2= average();
long sensor1 = (read1 + read2)/2;
Serial.print ("resistance bias =" );
Serial.println (read1-read2);
Serial.print ("sensor bias compensated value = ");
Serial.println (sensor1);
Serial.println ();
//send back the values
send(msg.set((long int)ceil(sensor1)));
// delay until next measurement (msec)
sleep(SLEEP_TIME);
}
void measure (int phase_b, int phase_a, int analog_input)
{
// read sensor, filter, and calculate resistance value
// Noise filter: median filter
for (i=0; i<NUM_READS; i++) {
// Read 1 pair of voltage values
digitalWrite(phase_a, HIGH); // set the voltage supply on
delayMicroseconds(25);
supplyVoltage = analogRead(analog_input); // read the supply voltage
delayMicroseconds(25);
digitalWrite(phase_a, LOW); // set the voltage supply off
delay(1);
digitalWrite(phase_b, HIGH); // set the voltage supply on
delayMicroseconds(25);
sensorVoltage = analogRead(analog_input); // read the sensor voltage
delayMicroseconds(25);
digitalWrite(phase_b, LOW); // set the voltage supply off
// Calculate resistance
// the 0.5 add-term is used to round to the nearest integer
// Tip: no need to transform 0-1023 voltage value to 0-5 range, due to following fraction
long resistance = (knownResistor * (supplyVoltage - sensorVoltage ) / sensorVoltage) ;
delay(1);
addReading(resistance);
Serial.print (resistance);
Serial.print ("\t");
}
}
// Averaging algorithm
void addReading(long resistance)
{
buffer[index] = resistance;
index++;
if (index >= NUM_READS) {
index = 0;
}
}
long average()
{
long sum = 0;
for (int i = 0; i < NUM_READS; i++) {
sum += buffer[i];
}
return (long)(sum / NUM_READS);
}
