MySensors Hydroponics Greenhouse project

[Thucar]

Got carried away. Added thermistor temperature readings and EC measurement. I have no idea if EC is working correctly at this point, without having the probe yet. I referenced the code by Michael Ratcliffe who did amazing job on utilizing an US power plug as a probe.
Another addition was to make all values poll-able. So you can get a fresh reading when needed without having to wait for the report time to tick over.

/**
 * 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.
 *
 *******************************
 *
 * REVISION HISTORY
 * Version 1.0 - Rait Lotamõis
 *
 * DESCRIPTION
 * First iteration of a Hydroponic greenhouse controller sketch.
 * Supports: 
 * 2 relays with individual push buttons
 * BH1750 Light sensor
 * Moisture sensor
 * 
 */

// Enable debug prints to serial monitor
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69

// Enable repeater functionality for this node
#define MY_REPEATER_FEATURE

#include <MySensors.h>
#include <Vcc.h>
#include <ResponsiveAnalogRead.h>
#include <SPI.h>
#include <BH1750.h>
#include <Wire.h>
#include <TimerOne.h>
#include <SmoothThermistor.h>

// Measurement and reporting settings
#define REPORT_INTERVAL           600 // define report interval in seconds for all sensors. This is when a full report is sent, no matter what
#define MOI_MEASUREMENT_INTERVAL  10 // Time in seconds, between consecutive measurements
#define MOI_REPORT_THRESHOLD      5 // The difference in % between two consecutive readings to send an immediate report
#define LUX_MEASUREMENT_INTERVAL  15 // Time in seconds, between consecutive measurements
#define LUX_REPORT_THRESHOLD      100 // The difference in Lux between two consecutive readings to send an immediate report
#define TMP_MEASUREMENT_INTERVAL  15 // Time in seconds, between consecutive measurements
#define TMP_REPORT_THRESHOLD      1 // The difference in degrees between two consecutive readings to send an immediate report
#define PPM_MEASUREMENT_INTERVAL  10 // Time in seconds, between consecutive measurements
#define PPM_REPORT_THRESHOLD      50 // The difference in ppm between two consecutive readings to send an immediate report

// Relay settings. TODO: Make it easy to use more than two relays
#define RLY_PIN_1   4
#define RLY_PIN_2   5
#define RLY_BTN_1   2 // Pin to use for a pushbutton switch. NB! Needs an interrupt pin
#define RLY_BTN_2   3 // Pin to use for a pushbutton switch. NB! Needs an interrupt pin
#define RLY_ON      0  // GPIO value to write to turn on attached relay
#define RLY_OFF     1 // GPIO value to write to turn off attached relay
#define RLY_ID_1    1 // MySensors Child ID
#define RLY_ID_2    2 // MySensors Child ID

// Soil Moisture settings
#define MOI_SENSE_PIN   A0 // Analog pin connecting to the probe
#define MOI_POWER_PIN   6 // Pin for powering the humidity sensor
#define MOI_0_PERCENT   0 // Probe output voltage at 0% moisture
#define MOI_100_PERCENT 2.5 // Probe output voltage in a glass of water
#define MOI_ID          3 // MySensors Child ID

// Lux sensor settings
#define LUX_ID 0 // MySensors Child ID

// Temperature sensor settings (NTC Thermistors)
#define TMP_SENSE_PIN   1 // Analog pin the first thermistor connects to NB! Use numeric values only. so instead of A0, A1, etc just use 0,1
#define TMP_MAX_SENSORS 1 // Number of thermistors connected. They need to be attached to sequential pins
#define TMP_USE_AREF    false // If your Arduino has the ARef pin available, you should use it
#define TMP_NOMINAL_RES 10000 // Nominal resistance of thermistors being used
#define TMP_SERIES_RES  12000 // Value of the voltage divider resistor
#define TMP_BETA        3950 // You will get the Beta coeficent from your thermistors datasheet
#define TMP_NOMINAL_T   25 // Nominal temperature for the thermistor
#define TMP_SAMPLES     10 // Number of samples to take
#define TMP_ID          10 //Mysensors Child ID

// PPM sensor settings
#define PPM_SENSE_PIN   A7 // Analog pin used for the probe
#define PPM_POWER_PIN   7 // Digital pin used to supply power to the probe
#define PPM_RESISTOR    560 // No less than 300 and no more than 1K resistor should be used. Around 500 gives the best resolution
#define PPM_CALIBRATION 1.38  // EC value of Calibration solution in s/cm
#define PPM_TEMP_COEF   0.019 // 0.019 is generaly considered the standard for plant nutrients [google "Temperature compensation EC" for more info]
#define PPM_TEMP_SENSOR 10 // Temperature sensor ID that is measuring your solution temperature
#define PPM_ID          4 // MySensors Child ID

// General settings
#define VCC_VOLTAGE_READ      5.0 // Actual supply voltage going to the VCC. Use a multimeter to check
#define VCC_VOLTAGE_REPORTED  4.97 // Set this to the same as above for your first boot. Then insert the value reported in the Serial window during boot
#define ONE_SECOND_IN_MICROS  500000 // Depends on your crystal. 8MHz crystal:500000, 16MHz crystal:1000000, etc. If your time intervals are off, this is the reason

// PPM variables
int ppmR1 = PPM_RESISTOR;
int ppmRa = 25;
float ppmTempFinish = 0;
float ppmTempStart = 0;
float lastEC = 0;
int lastPPM = 0;
ResponsiveAnalogRead analogPpm(PPM_SENSE_PIN, false);
MyMessage msgPpm(0,V_EC);

// Soil Moisture variables
float cal0 = MOI_0_PERCENT; 
float cal100 = MOI_100_PERCENT; 
ResponsiveAnalogRead analogMoi(MOI_SENSE_PIN, false);
MyMessage msgMoi(0,V_LEVEL);
float lastMoisture = 0;

// Relay variables
MyMessage msgRly(0,V_STATUS);
bool rlyState1 = false;
bool rlyState2 = false;

// Lux sensor variables
BH1750 luxSensor;
MyMessage msgLux(0, V_LIGHT_LEVEL);
uint16_t lastLux = 0;

// Temperature sensor variables
float lastTemperatures[TMP_MAX_SENSORS];
MyMessage msgTmp(0,V_TEMP);

// VCC Monitoring for calculations
const float VccCorrection = VCC_VOLTAGE_READ/VCC_VOLTAGE_REPORTED;
Vcc vcc(VccCorrection);

// General variables
bool receivedConfig = false;
bool metric = true;
long reportTimer = REPORT_INTERVAL;
long moiTimer = MOI_MEASUREMENT_INTERVAL;
long luxTimer = LUX_MEASUREMENT_INTERVAL;
long tmpTimer = TMP_MEASUREMENT_INTERVAL;
long ppmTimer = PPM_MEASUREMENT_INTERVAL;
const unsigned long debounceTime = 50;

void before()
{

}

void setup()
{
  // Initialize the timer interrupt for sending sensor reports
  Timer1.initialize(ONE_SECOND_IN_MICROS); 
  Timer1.attachInterrupt(countDownOneSecond);

  // Initialize and set relays to last known states (using eeprom storage)
  pinMode(RLY_PIN_1, OUTPUT);
  pinMode(RLY_PIN_2, OUTPUT);
  rlyState1 = loadState(RLY_ID_1);
  rlyState2 = loadState(RLY_ID_2);
  digitalWrite(RLY_PIN_1, rlyState1?RLY_ON:RLY_OFF);
  digitalWrite(RLY_PIN_2, rlyState2?RLY_ON:RLY_OFF);

  // Set the interrupts for relay buttons
  pinMode(RLY_BTN_1, INPUT_PULLUP);
  pinMode(RLY_BTN_2, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(RLY_BTN_1), toggleRly1, FALLING);
  attachInterrupt(digitalPinToInterrupt(RLY_BTN_2), toggleRly2, FALLING);
  
  // Initialize Soil Moisture power pin
  pinMode(MOI_POWER_PIN, OUTPUT);
  digitalWrite(MOI_POWER_PIN, LOW);

  // Initialize the Lux sensor
  luxSensor.begin();

  // Initialize the PPM sensor
  pinMode(PPM_POWER_PIN , OUTPUT );
  digitalWrite(PPM_POWER_PIN , LOW );
  pinMode(PPM_SENSE_PIN,INPUT);
  ppmR1=(ppmR1+ppmRa);

  // Take and report voltage readings
#ifdef MY_DEBUG
  Serial.print("Measuring VCC voltage as: ");
  Serial.print(vcc.Read_Volts());
  Serial.println("V");
#endif
}

void presentation()
{
  // Send the sketch version information to the gateway and Controller
  sendSketchInfo("Greenhouse Node", "0.3");

  // Register Relays
  present(RLY_ID_1, S_BINARY);
  present(RLY_ID_2, S_BINARY);

  // Register Soil Moisture sensor
  present(MOI_ID, S_MOISTURE);
  
  // Register Lux sensor
  present(LUX_ID, S_LIGHT_LEVEL);

  // Register PPM sensor
  present(PPM_ID, S_WATER_QUALITY);

  // Register temperature sensors
  for (int i=0; i<TMP_MAX_SENSORS; i++) {   
     present(TMP_ID+i, S_TEMP);
  }

}


void loop()
{

  // Update the relay outputs
  updateRelays();
  
  // Get Soil Moisture levels if it is time
  if (moiTimer == 0){
#ifdef MY_DEBUG
    Serial.print("Taking Moisture measurements: ");
#endif
    readMoisture();
#ifdef MY_DEBUG
    Serial.print(lastMoisture);
    Serial.println("%");
#endif
    moiTimer = MOI_MEASUREMENT_INTERVAL;
  }

  // Get Lux level if it is time
  if (luxTimer == 0){
#ifdef MY_DEBUG
    Serial.print("Taking Lux measurements: ");
#endif
    readLux();
#ifdef MY_DEBUG
    Serial.print(lastLux);
    Serial.println("lux");
#endif
    luxTimer = LUX_MEASUREMENT_INTERVAL;
  }

// Get PPM level if it is time
  if (ppmTimer == 0){
#ifdef MY_DEBUG
    Serial.println("Taking PPM measurements: ");
#endif
    readPPM();
#ifdef MY_DEBUG
    Serial.print(lastPPM);
    Serial.println("ppm");
    Serial.print(lastEC);
    Serial.println("s/cm");
#endif
    ppmTimer = PPM_MEASUREMENT_INTERVAL;
  }

  // Get Temperatures if it is time
  if (tmpTimer == 0){
#ifdef MY_DEBUG
    Serial.println("Taking Temperature measurements: ");
#endif
    readTemperatures();
#ifdef MY_DEBUG
for (int i=0; i<TMP_MAX_SENSORS;i++){
  Serial.print(TMP_ID+i);
  Serial.print(": ");
  Serial.print(lastTemperatures[i]);
  Serial.println("C");
}
#endif
    tmpTimer = TMP_MEASUREMENT_INTERVAL;
  }
  
  // Send reports it if is time
  if (reportTimer == 0){
#ifdef MY_DEBUG
    Serial.println("Sending reports.");
#endif
    sendReports();
    reportTimer = REPORT_INTERVAL;
  }
  
}

void receive(const MyMessage &message)
{
  if (message.isAck()) {
#ifdef MY_DEBUG
     Serial.println("This is an ack from gateway");
#endif
     return;
  }
  
  if (message.type==V_STATUS) {
      // Change relay state
      int outputPin = (message.sensor == RLY_ID_1)?RLY_PIN_1:RLY_PIN_2;
      digitalWrite(outputPin, message.getBool()?RLY_ON:RLY_OFF);
      // Store state in eeprom
      saveState(message.sensor, message.getBool());
#ifdef MY_DEBUG
      // Write some debug info
      Serial.print("Incoming change for relay:");
      Serial.print(message.sensor);
      Serial.print(", New status: ");
      Serial.println(message.getBool());
#endif
      // Update the state variables
      rlyState1 = loadState(RLY_ID_1);
      rlyState2 = loadState(RLY_ID_2);
  } else if (message.type==V_TEMP){ // Return temperature readings when queried
    readTemperatures();
    send(msgTmp.setSensor(message.sensor).set(lastTemperatures[message.sensor-TMP_ID],1));
  } else if (message.type==V_LEVEL && message.sensor == MOI_ID){ // Return moisture readings when queried
    readMoisture();
    send(msgMoi.set(lastMoisture,1));
  } else if (message.type==V_LEVEL && message.sensor == LUX_ID){ // Return Light level readings when queried
    readLux();
    send(msgLux.set(lastLux));
  } else if (message.type==V_EC){
    readPPM();
    send(msgPpm.set(lastPPM));
  }
}

// Check if a button has been pressed, meaning we should flip the relay
void updateRelays(){
  bool oldState1 = loadState(RLY_ID_1);
  bool oldState2 = loadState(RLY_ID_2);

  if (oldState1 != rlyState1){
    digitalWrite(RLY_PIN_1, rlyState1?RLY_ON:RLY_OFF);
    saveState(RLY_ID_1, rlyState1?true:false);
    send(msgRly.setSensor(RLY_ID_1).set(rlyState1?true:false), false);
  }

  if (oldState2 != rlyState2){
    digitalWrite(RLY_PIN_2, rlyState2?RLY_ON:RLY_OFF);
    saveState(RLY_ID_2, rlyState2?true:false);
    send(msgRly.setSensor(RLY_ID_2).set(rlyState2?true:false), false);
  }
}

// Send all reports using last known values
void sendReports(){
  
  // Send Lux
  send(msgLux.set(lastLux));
  
  // Send Moisture
  send(msgMoi.set(lastMoisture,1));

  // Send PPM
  send(msgPpm.set(lastPPM));

  // Send Temperatures
  for (int i=0; i< TMP_MAX_SENSORS;i++){
    send(msgTmp.setSensor(TMP_ID+i).set(lastTemperatures[i],1));
  }
  
}

// Get the PPM levels
void readPPM(){
  float EC = 0;
  float EC25 = 0;
  long PPM = 0;
  float raw = 0;
  float Vin = vcc.Read_Volts();
  float Vdrop = 0;
  float Rc = 0;
  float val = 0;
  digitalWrite(PPM_POWER_PIN, HIGH);
  wait(10);
  analogPpm.update();
  raw = analogPpm.getValue();
  digitalWrite(MOI_POWER_PIN, LOW);

  Vdrop = ((Vin * raw) / 1024.0);
  Rc =(Vdrop*ppmR1)/(Vin-Vdrop);
  Rc = Rc-ppmRa;
  EC = 1000/(Rc*PPM_CALIBRATION);

  EC25 = EC / (1 + (PPM_TEMP_COEF * (lastTemperatures[PPM_TEMP_SENSOR - TMP_ID] - 25.0)));

  PPM = EC25 * 1000 / 2;

  if (abs(lastPPM - PPM) > PPM_REPORT_THRESHOLD && reportTimer > 0){
    send(msgPpm.set(PPM));
  }
  
  lastPPM = PPM;
  lastEC = EC25;
  
}

// Get the light level values
void readLux(){
  uint16_t lux = luxSensor.readLightLevel();
  // Check if the difference between previous reading and this one is enough to warrant an immediate report
  if ((abs(lux-lastLux) > LUX_REPORT_THRESHOLD) && reportTimer > 0){
    send(msgLux.set(lux));
  }
  lastLux = lux;
}

// Get the temperature values
void readTemperatures(){
  int i;
  bool sendReport = false;
#ifdef MY_DEBUG
    Serial.println("Temperatures:");
#endif
  for (i=0;i<TMP_MAX_SENSORS;i++){
    SmoothThermistor smoothThermistor(TMP_SENSE_PIN+i,              // the analog pin to read from
                                  ADC_SIZE_10_BIT,             // the ADC size
                                  TMP_NOMINAL_RES,             // the nominal resistance
                                  TMP_SERIES_RES,              // the series resistance
                                  TMP_BETA,                    // the beta coefficient of the thermistor
                                  TMP_NOMINAL_T,               // the temperature for nominal resistance
                                  TMP_SAMPLES);                // the number of samples to take for each measurement
    smoothThermistor.useAREF(TMP_USE_AREF);
    float temp = smoothThermistor.temperature();
    // Send in the new temperature
    if ((abs(temp-lastTemperatures[i]) > TMP_REPORT_THRESHOLD) && reportTimer > 0){
      send(msgTmp.setSensor(TMP_ID+i).set(temp,1));
    }
    // Save new temperatures for next compare
    lastTemperatures[i] = temp;
  }
  
  
}

// get the soil moisture values
void readMoisture(){
  float v = vcc.Read_Volts();
  int aRead = readSoil();
  float voltage = (aRead * v / 1024.0);
  float moisture = voltage * 100/cal100;
  // Check if the difference between previous reading and this one is enough to warrant an immediate report
  if ((abs(moisture-lastMoisture) > MOI_REPORT_THRESHOLD) && reportTimer > 0){
    send(msgMoi.set(moisture,1));
  }
  lastMoisture = moisture;
}

// Perform the actual powering up and measurement process for Soil moisture sensor. TODO: Does it really need a separate function?
int readSoil()
{
  int val;
  digitalWrite(MOI_POWER_PIN, HIGH);
  delay(10);//wait 10 milliseconds
  analogMoi.update();
  val = analogMoi.getValue();
  digitalWrite(MOI_POWER_PIN, LOW);
  
  return val;
}

// Interrupt Service Routines
// TODO: Would love to use the same ISR for both (all?) relays
void toggleRly1(){
  static unsigned long previousStateChangeMillis = 0;
  bool pinState = digitalRead(RLY_BTN_1);
  if (pinState == LOW) { // only falling events
    if ((millis() - previousStateChangeMillis) > debounceTime) { // debounce
      rlyState1 = !rlyState1;
    }
  }
  previousStateChangeMillis = millis();
}

void toggleRly2(){
  static unsigned long previousStateChangeMillis = 0;
  bool pinState = digitalRead(RLY_BTN_2);
  if (pinState == LOW) { // only falling events
    if ((millis() - previousStateChangeMillis) > debounceTime) { // debounce
      rlyState2 = !rlyState2;
    }
  }
  previousStateChangeMillis = millis();
}

void countDownOneSecond(void) {
  if (ppmTimer > 0){
    ppmTimer--;
  }
  if (moiTimer > 0){
    moiTimer--;
  }
  if (tmpTimer > 0){
    tmpTimer--;
  }
  if (luxTimer > 0){
    luxTimer--;
  }
  if (reportTimer > 0) {
    reportTimer--;
  }
}

[Nick Willis]

This looks very interesting! I also want to get my gardening more automated as I live in an apartment with a roof terrace which makes using soil hard work (no lift/elevator and we're on the 5th floor!). I grow tomatoes, peppers, chillies etc but keeping up with the watering on my south facing terrace is hard work. Fertilising regularly is even more hard work. I installed a basic irrigation system but I've not been successful in mixing in liquid fertiliser at the right concentrations. So I'm back to measuring it into a watering can which takes forever.
So I'm wondering if hydroponics might be the way to go. What sort of equipment are you using for hydroponics? Would it work if left outside without protection in the rain etc? If not then maybe I'm better trying to improve on my irrigation system.. and somehow finding a way to operate it with fertiliser at a specific concentration.
Will follow this all with interest...

[Thucar]

First of all let me emphasis that this is going to be my first hydroponic setup. So I have no experience to draw on. That being said, I am seeing a lot of information on outdoor hydroponic setups. Rain water getting into your solution is to be prevented as much as possible, but it’s no disaster if some does end up in your tank.

For tomatoes, peppers, cucumbers and other tall plants, people seem to prefer something like the Dutch bucket system. If you get buckets with lids, you can just drill a 2 inch hole for the plant to poke through and keep most of the rain out.

For smaller plants like leafy greens, herbs and such, the PVC pipe system seems great. You could set it up either as a NFT or a Flood&Drain system. The benefit again is that the rain water will not have a way into your nutrient solution.

[Thucar]

To quote the classics - “Well, that escalated quickly.”

While waiting for the sensors to arrive, I started mulling over the entire project in my head. And I started thinking about scaling. My greenhouse is only 3 meters long but my parents greenhouse is almost 30 meters. Routing wires for soil sensors around the place is no fun.

So that got me thinking - does it need to be one node? And that in turn got me thinking - does it even have to be a node? Maybe a gateway would be the way to go?

So this is my current plan - a GSM/Wifi gateway with the general and more power hungry components( pH, EC, relative air humidity and ambient temp, relays). The gateway would be located near the pumps, sumps and other tech in the greenhouse.

Then the rest of the greenhouse can be filled with any number of sensors to monitor soil moisture, temperature and light levels at different places.

GSM gateway is almost finished, hopefully I can wrap it up tomorrow.

And as a final touch, I realized a controller of that kind of functionality could use a local user input. So it’s going to have a LCD and some buttons for set-up and things like starting/stopping pumps for maintenance.

[Thucar]

Update:
LCD + rotary click encoder working
ArduinoMenu4 in place and easily expandable.
Relay control works 100%
EC/ppm measurement in place, not yet 100% working
SHT21 code in place, can confirm if working or not once the darn thing arrives

Some eye candy:

[elcaron]

A thought I had recently: Those moisture pitchforks are usually HASL coated. Do I really want that in the soil of a plant I probably want to eat? Any thoughts anyone?

[Nca78]

@elcaron said in MySensors Hydroponics Greenhouse project:

A thought I had recently: Those moisture pitchforks are usually HASL coated. Do I really want that in the soil of a plant I probably want to eat? Any thoughts anyone?

The answer is no :)

[Thucar]

@elcaron said in MySensors Hydroponics Greenhouse project:

HASL

The pitchfork i'm currently using has solid copper traces on the forks. For more long term use I'm planning on switching to capacitive soil moisture sensors. Those can be additionally coated with epoxy resin for example for added longevity.

[Thucar]

Now that the GSM Gateway is done, I can start focusing more on the Greenhouse controller. I’m still waiting for the two most important components though - the pH sensor module and the stainless steel EC sensor probe. I’ve stumbled on another very good post on the EC topic which I’ll have to work through: https://thecavepearlproject.org/2017/08/12/measuring-electrical-conductivity-with-an-arduino-part1-overview/

[Thucar]

Got some work done on the hardware side of things. Drainage is done, next up is feed part.

[Thucar]

A long overdue update.

In the end I basically ended up using a GSM gateway with a LCD and couple sensors (air temperature and air humidity) and two relays. The relays control my Dutch bucket system pump and ventilation fans.

As a separate sensor I'm using a Z-Wave multisensor to keep track of nursery temperatures and lux levels.

The pH meter module did arrive but I do not feel comfortable keeping it submerged in the nutrient solution at all times so I've been just taking a sample of the nutrient solution from the tank after mixing a new batch, and testing it indoors, at the computer.

As for the EC meter, I failed to get any of the "arduino only" examples to produce reliable readings. So I've ordered 5 PCB's for this thing: https://www.sparkyswidgets.com/portfolio-item/miniec-i2c-ec-interface/
Once they arrive, I'll see if I can get more reliable results with a separate module.

So far the whole thing has been running almost perfectly. The only drawback is an occasional reboot of the gateway when switching off the Dutch bucket system pump. I'm using two separate power sources for Arduino and the pump, Added a 1000uF cap to the Arduino power rail and a flyback diode across the pumps power lines. Still getting that reboot about 50% of the time.

Some pics to wrap up my rant.
PS. Yes, that's a webcam in my greenhouse. It's taking hourly snapshots for a timelapse :)

My NFT rails for herbs. A good eye can spot some dill, basil and cilantro plants in there.

That's my "Nursery" - an old fish tank I can cover with a piece of glass when night temps dip below 10C

That's my Fibaro Motion sensor. An easy way to get some essential readings. Like the length of day, hours of sunlight, temperature.

This is my ratsnest. I should have moved the relays to a separate enclosure further away. Right now I think the arc when breaking contact is what's causing an EMP pulse and rebooting my Mega.

Ventilation fans. The temps soared to high 40's and low 50's with door and both ceiling hatches wide open. The fans kick in when air temp reaches 25C

[gohan]

Are you using optocouplers to drive the relays?

[Thucar]

Yes, the relay module has optocouplers separating data lines from the relays.

[gohan]

Try disconnecting the load from the relay and see if it still triggers the reboot. If you still have the issue, try disconnect the relays and try again. You need to start narrowing down the possible causes

[Thucar]

Disconnecting the load eliminates the issue flat out.

I think your previous question just triggered a lightbulb. While the module does have optocouplers in place, I have the VCC bridging jumper in place. So essentially Arduino is still sharing the power with relay coils. I'll install a step-down to get a 5V line from the pump power supply and use that to drive the relays. I believe that should eliminate my reboot issues.

[Thucar]

Confirmed. Removing the jumper and using a power supply separate from the arduino’s has cured it from reboot issues.

[Thucar]

A quick video update: https://youtu.be/vnUFV_amSPQ
The tomatos and peas are trying to go through the roof. Cucumbers are close to follow. They are all aiming for the ventilation hatches - I think they are planning a grand escape...

The NFT system pump stopped working coupe weeks after setting it up. Have not gotten around to ordering a new pump. That will be a project for next year.