Multiple onewire sensors problem



  • Hi
    I have a problem with a nano board with multiple onewire sensors on it, using Home Assistant. Only one sensor is picked up in Home assistant. I think it is to do with the presentation part of the sketch, and have tried a few different things, but no luck. Could someone help me out please with the mods required.

    Here is my code

    /**
     * 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
     *
     * Example sketch showing how to send in DS1820B OneWire temperature readings back to the controller
     * http://www.mysensors.org/build/temp
     */
    
    
    // Enable debug prints to serial monitor
    #define MY_DEBUG 
    
    // Enable and select radio type attached
    #define MY_RADIO_NRF24
    //#define MY_RADIO_RFM69
    
    #include <SPI.h>
    #include <MySensors.h>  
    #include <DallasTemperature.h>
    #include <OneWire.h>
    
    #define COMPARE_TEMP 1 // Send temperature only if changed? 1 = Yes 0 = No
    
    #define ONE_WIRE_BUS 3 // Pin where dallase sensor is connected 
    #define MAX_ATTACHED_DS18B20 16
    unsigned long SLEEP_TIME = 5000; // Sleep time between reads (in milliseconds)
    OneWire oneWire(ONE_WIRE_BUS); // Setup a oneWire instance to communicate with any OneWire devices (not just Maxim/Dallas temperature ICs)
    DallasTemperature sensors(&oneWire); // Pass the oneWire reference to Dallas Temperature. 
    float lastTemperature[MAX_ATTACHED_DS18B20];
    int numSensors=0;
    bool receivedConfig = false;
    bool metric = true;
    // Initialize temperature message
    MyMessage msg(0,V_TEMP);
    
    void before()
    {
      // Startup up the OneWire library
      sensors.begin();
    }
    
    void setup()  
    { 
      // requestTemperatures() will not block current thread
      sensors.setWaitForConversion(false);
    }
    
    void presentation() {
      // Send the sketch version information to the gateway and Controller
      sendSketchInfo("Temperature Sensor", "1.1");
    
      // Fetch the number of attached temperature sensors  
      numSensors = sensors.getDeviceCount();
    
      // Present all sensors to controller
      for (int i=0; i<numSensors && i<MAX_ATTACHED_DS18B20; i++) {   
         present(i, S_TEMP);
      }
    }
    
    void loop()     
    {     
      // Fetch temperatures from Dallas sensors
      sensors.requestTemperatures();
    
      // query conversion time and sleep until conversion completed
      int16_t conversionTime = sensors.millisToWaitForConversion(sensors.getResolution());
      // sleep() call can be replaced by wait() call if node need to process incoming messages (or if node is repeater)
      sleep(conversionTime);
    
      // Read temperatures and send them to controller 
      for (int i=0; i<numSensors && i<MAX_ATTACHED_DS18B20; i++) {
    
        // Fetch and round temperature to one decimal
        float temperature = static_cast<float>(static_cast<int>((getControllerConfig().isMetric?sensors.getTempCByIndex(i):sensors.getTempFByIndex(i)) * 10.)) / 10.;
    
        // Only send data if temperature has changed and no error
        #if COMPARE_TEMP == 1
        if (lastTemperature[i] != temperature && temperature != -127.00 && temperature != 85.00) {
        #else
        if (temperature != -127.00 && temperature != 85.00) {
        #endif
    
          // Send in the new temperature
          send(msg.setSensor(i).set(temperature,1));
          // Save new temperatures for next compare
          lastTemperature[i]=temperature;
        }
      }
      sleep(SLEEP_TIME);
    }
    Insert Code Here
    

  • Mod

    Also log of node startup could be helpful



  • Well I don't get this. Today both temp sensors are showing. Yesterday only one showed all day. Anyone any ideas why it would take so long for the second sensor to be detected.


  • Mod

    Wiring problem? 😀😅



  • 1-wire doesnt do well with star wiring, linear is better, choosing the right pull up resistor is important, (4.7k is common, but not always the best), parasitic power? If so longer conversion time. Search "reliable 1-wire", there are some good wiring guides out there. It looks like you have 5000 millis fornconversion, should be long enough. Maybe too long? I dont know how 1-wire handles holding on to the reading, maybe combined with parasitic power they are shitting down before you get the reading. In parasite mode you have to cycle them enough to keep them powered up.


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