Create relay free potential free switch.

[Rene046]

Hi there,

i need some help with an idea i need...
I looking far a way to control a potential free contact to control an water lock, but without using a relay. if my water lock sees 10K on its connection it keeps it closed so no watering, if it sees 0 ohm it will have permission to water. my plants
.
i was thinking to use an opto coupler but those i now need a voltage going tru on the output... or am i wrong.

or maybe some kind of hal sensor with internal coil controlled by an arduino

[gohan]

I didn't get what's the problem with the relay

[Rene046]

battery powered project....

[gohan]

Transistor? Latching relay? I am just throwing ideas since I haven't fully understood your project.

[Nca78]

@Rene046 said in Create relay free potential free switch.:

battery powered project....

Why not just use a latching relay ?

[Rene046]

because i dont want the water lock stay open after power lost.

[Rene046]

Ok i explain.

i have and Gardena Watering computer, here i want to connect a controller on battery to
All this controller has to do via Mysensors is open or close a an switch (the 2 wires of this switch go inside the gardena computer that is looking for an 10k resistance to stop watering the plants, and an open switch 0 ohm to water the plants.

Some distance further i have an other node that's measuring soil moisture,

I have this now running by using normal relays, but using 2 of them (2 garden computers ) they use allot of battery power while watering so i was hoping there are some more better options.

[gohan]

If you are afraid of wasting too much water, just run a command in setup function that checks the status of latching relay and turns it off. In addition there are many arduino projects for watering plants you can look for inspiration

[Nca78]

And there are also some latching relays with 2 latches, one to switch on, one to switch off.
You can just switch off at the beginning of your sketch.
It's even possible to do that with hardware, to send a pulse to the "switch off" latch when the system is started. So even if your sketch fails to start, your relay will be off.

[Rene046]

will give it a try.

this is the sketch i want to implement this in:
It will be a repeater node,
I would like to have 2 Relays on pins D3,D4
And a temperature sensor on D5 (DS1820)
Eventually an voltage sense pin A3

/*
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * http://www.mysensors.org/build/relay
 */

// Enable debug prints to serial monitor
#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_RFM69
#define MY_RF24_PA_LEVEL RF24_PA_MAX

// Enabled repeater feature for this node
#define MY_REPEATER_FEATURE
#define MY_NODE_ID 1
#include <SPI.h>
#include <MySensors.h>
#include <Bounce2.h>
#include <SPI.h>
#include <DallasTemperature.h>
#include <OneWire.h>

#define COMPARE_TEMP 1 // Send temperature only if changed? 1 = Yes 0 = No

#define RELAY_PIN1  3  // Arduino Digital I/O pin number for relay
#define BUTTON_PIN  7  // dont need this one remove
#define CHILD_ID 1
#define RELAY_ON 1
#define RELAY_OFF 0

Bounce debouncer = Bounce();
bool state = false;
bool initialValueSent = false;

MyMessage msg(CHILD_ID, V_STATUS);

void setup()
{
  // Setup the button
  //pinMode(BUTTON_PIN, INPUT_PULLUP);

  // After setting up the button, setup debouncer
  //debouncer.attach(BUTTON_PIN);
  //debouncer.interval(10);

  // Make sure relays are off when starting up
  digitalWrite(RELAY_PIN1, RELAY_OFF);
  // Then set relay pins in output mode
  pinMode(RELAY_PIN1, OUTPUT);

  // Set relay to last known state (using eeprom storage)
  state = loadState(CHILD_ID);
  digitalWrite(RELAY_PIN1, state?RELAY_ON:RELAY_OFF);
}

void presentation()  {
  // Startup initialize MySensors library. Set callback for incoming messages. 
   
  
  sendSketchInfo("Lamp", "1.0");
  present(CHILD_ID, S_BINARY);
  
}

void loop()
{
  if (!initialValueSent) {
    Serial.println("Sending initial value");
    send(msg.set(state?RELAY_ON:RELAY_OFF));
    Serial.println("Requesting initial value from controller");
    request(CHILD_ID, V_STATUS);
    wait(2000, C_SET, V_STATUS);
  }
  if (debouncer.update()) {
    if (debouncer.read()==LOW) {
      state = !state;
      send(msg.set(state?RELAY_ON:RELAY_OFF), true); // Send new state and request ack back
    }
  }
 }

void receive(const MyMessage &message) {
  if (message.isAck()) {
     Serial.println("This is an ack from gateway");
  }

  if (message.type == V_STATUS) {
    if (!initialValueSent) {
      Serial.println("Receiving initial value from controller");
      initialValueSent = true;
    }
    // Change relay state

    state = (bool)message.getInt();
    digitalWrite(RELAY_PIN1, state?RELAY_ON:RELAY_OFF);
    send(msg.set(state?RELAY_ON:RELAY_OFF));
    // Store state in eeprom
    saveState(CHILD_ID, state);

    // Write some debug info
    Serial.print("Incoming change for sensor:");
    Serial.print(message.sensor);
    Serial.print(", New status: ");
    Serial.println(message.getInt());
  }
}```

[Rene046]

So far 1 relay works perfect adding a second one will be a bid harder because the sketch samples i found use more than 2 i would like to know how to add just a second one.
also in this sketch in need to find out hoe to remove the button function.
Adding the temperature sensor seems for me very hard, because i would like to call it every 5 minutes without interrupting the repeater. (No Sleep can be used).
if i know how to call every 5 minutes the temperature, i think i'll be able to add the also the adc code.

I someone could point me to some code sample i would be very happy...

[gohan]

Just use wait() instead of sleep

[Rene046]

Thanks Gohan,

Will the repeater function keep working...... ? more like an interrupt when something is seen ?

[gohan]

The wait is specific for keeping the communications going while pausing the loop