Office plant monitoring

[Dennis van der Wolf]

@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);
}

[ronnyandre]

Thanks for this great solution @mfalkvidd! It works great when my Arduino Pro Mini is connected to the computer, but not when I try to run it off a battery pack.

I have a Pro Mini 3.3v connected to a 0.8-3.3v step up from a battery pack (2xAA; 3v). And then I have connected the radio and sensor to VCC on the Pro Mini. When the Pro Mini is connected to my iMac, Domoticz receives everything as it should. However, when I disconnect it from the computer and connect the battery source, all LEDs light as they should, indicitating that they have power, but it won't connect to Domoticz over NRF24.

I have used a multimeter to check the voltage and if the radio receives enough power, and it does. All power/ground pins show around 3.3v. Any ideas to debug what's wrong?

[Fat Fly]

@joshmosh said in Office plant monitoring:

mfalkvidd

Where i find mfalkvidd's sketch ?

[mfalkvidd]

@ronnyandre a multimeter is unfortunately not sensitive enough to display if there is enough power during the short bursts when the radio is active.

Most step-ups don't deliver power that is stable enough. You could try adding more/larger capacitors, but from what I have seen in the forum, people seldom get thing working reliably with a step-up. I have never tried using step-up myself, I use power directly from the batteries.

If you haven't checked already, see the troubleshooting chart at https://forum.mysensors.org/topic/666/debug-faq-and-how-ask-for-help/

[mfalkvidd]

Where i find mfalkvidd's sketch ?

At github, but be aware that this code is for MySensors 1.x. It does not work with MySensors 2.x.

[ronnyandre]

@mfalkvidd Thanks for the quick answer! I also read on the page for battery powered sensors that the step up generates alot of noise that can interfere with the radio, and that a solution might be to add capacitators (which I already tried), but also powering the radio directly from batteries. I'll try that later today. Thanks! :smiley:

And thank you for the link to the troubleshooting. It's now bookmarked! :wink:

[Fat Fly]

Please somebody help me add to skech one relay for water pump. I use this in Domoticz. I do not want build other hardware for this.It is possible ?

[gohan]

Just copy the relay code from https://www.mysensors.org/build/relay and add it your sketch and make necessary changes to adapt it: like setting child_id in presentation

[Fat Fly]

@gohan I make something this. Please look if all is right. My software writer skill is low. :) Some small errors. :)
https://pastebin.com/8LWpgb8L

[gohan]

because you are using old code, you need to convert it from libraries 1.5 to 2.x: there is a guide to do that

[Fat Fly]

Can i use old libraries and gateway version 2.1 ?

[gohan]

You can downgrade libraries and use old examples, but I'd suggest to stick to the new version

[Fat Fly]

@gohan said in Office plant monitoring:

but I'd suggest to stick to the new version

I try but idonotknow. :)

[Fat Fly]

@gohan
Please help with small errors. https://pastebin.com/VRXyT8Ut I try for library 2.x

[fhenryco]

It's a pity that at least one sketch for the analog reading of moisture sensor is not v2 compatible and made available on the main page ... i have no idea if making it v2 compatible would be a hard job...even if it's just a question of changing some library calls i'm afraid i don't have the skill for that...

[mfalkvidd]

My Bonsai tree humidity node celebrates 2 years on battery today!

During these two years, the gateway has received 146,528 updates on humidity level (and an additional 30,870 updates on voltage level).

The battery level has gone from 3.187V to 3.049, which means an average drop of 0,0058V per month. Assuming I let it go down to 2.34V (limit for 8MHz according to the datasheet) and that the voltage drop is linear, I should get (3.187-2.34)/0.0058 = 146 months = ~12 years. There are several error sources in this calculation, but it looks like battery life will be quite good.

Here are the voltage and humidity graphs for the last year.

As you can see, there was a problem in November. I was asked to verify the battery voltage reading by using a multimeter. When I opened the box to do that, I must have tripped something because the node got caught in some sort of loop, consuming battery. I restarted the node and the batteries recovered almost to the level they had before the problem occurred.

Last year's report: https://forum.mysensors.org/post/52232

[gohan]

@mfalkvidd said in Office plant monitoring:

and that the voltage drop is linear

You wish!!! :D

[mfalkvidd]

@gohan no actually I don't. The voltage drop is normally a s-shaped curve that is very flat in the middle. That means I am experiencing a higher drop at the beginning. That's likely the reason that the prediction after 2 years is more than 10% longer battery life than the prediction after 1 year was.

[gohan]

Yes, it depends when the voltage starts to drop significantly, but unless you have tested another battery before it is hard to know in advance 😀

[mfalkvidd]

@gohan alkaline batteries in general have been tested quite extensively and don't deviate much from the S-curve characteristics.