Hello,

few days ago I accidentally came across mysensors (how is it that I did not find it earlier as I am looking into rpi, arduino and home automation for about 2 years?) and I was exited from the first moment . For some time now I was working on several small sensors for my home but did not really like any of the solutions I met so far - my idea was ethernet + poe + rest api + simple progressive mobile UI. Closest I got was arduino pro mini with W5500 + 5V poe splitter + custom sketch using webduino to provide REST API + mozilla iot gateway.

I had (nearly) finished the HW for my window/door reed switches. But I got into trouble with REST API + mozilla iot gateway. Testing the REST API worked ok from browser but somehow the mozilla iot gateway was unable to load all the presented switches reliably. I have to say that until this problem I had quite a good experience with it - I had it connected to few thermometers and relays to operate heating.

I saw the sample sketches for mysensors + mycontroller.org and it "just clicked" to my idea. I edited the sketch and installed mycontroller and successfully tested both Ethernet Gateway and MQTT Gateway in few hours. I think I will stick with MQTT for more compatibility (I did not find any description about the mysensors communication protocol so I have no idea how standardized it is).

So I want to share my HW + say thanks for the great project!

Designed to be powered over usb micro (so it can run without poe) as these chargers are everywhere now.

The barrel connector is temporary until I modify the poe splitter output to usb micro.

Sample connection - I have such reed switches installed in my windows and doors.

Of course I will be happy for any constructive criticism and suggestions (I do not have any education in electronics so try not to be very harsh about my circuit design and soldering though ).

Prototype of room sensor for stardard electric box

• arduino pro mini 3.3V
• sx1276 radio
• bme680
• 2x1.5V AA battery holder
• battery measuring circuit according to https://www.mysensors.org/build/battery
• ABB Tango cover (drilled)

Cover is not fully closed to allow air circulation. But I would preffer some method to drill holes/grill into it - any tips to get decent looking result?

Hello

(brainstorming)

If you have the "original choice selector" you can tap to each wire and see what happens over individual wires when you press each button. An then simulate this from MCU (like arduino).

Or open the "original choice selector" and connect wires to the existing buttons. (That will probably void warranty.) That wires then you can connect to some MCU and "push" the buttons programmatically.

Tomas

Hello, also beginner here so take my advice with some reserve.

1 - It seems to me that your ethernet connection does not work - https://www.mysensors.org/apidocs/group__MyGatewayTransportgrp.html

17:21:06.386 -> 2580 !GWT:TIN:ETH FAIL

Can you ping the gateway?

2 - I am also using openHab but with MQTT gateway and MQTT binding as I did not find mysensors binding in the official list. But there is no autodiscovery - but I prefer to configure it manually anyway.

I would like to thank everyone for suggestions and comments.

I did 3 quick tests with two SX1276 based chips (868MHz LoRa) I already had.

I made simple 5V poe powered mysensors mqtt gateway with arduino pro mini 3.3V, W5500 lite and SX1276 radio

Simple 9V battery powered mysensors passive node with arduino pro mini 3.3V, BME680 (for some reason the sensor does not work when connected over SPI with the radio module at the same time - I have to investigate that ) and SX1276 radio

First test was inside house - I placed the node inside the freezer on the opposite side of house (approx 15m from gw) with concrete ceiling between. All messages were delivered.

Second test was outside the house - I placed the node under the beehives (approx 50m from gw). All messages were delivered.

Third test was also outside the house - I placed the node at the end of our property (approx 140m from gw). But no message was delivered.

I expected 140m would not be problem for LoRa chip but I think this may be improved with some antenna fiddling. But overall I am very happy with the results. So my current decision is to go with this setup but to use 2 or 3 1.5V AA batteries instead of 9V.

@zboblamont It is not electrical noise but audio noise I can hear. Sorry if I use improper terms.

MYS PoE MQTT Gateway with 868Mhz LoRa radio in IP55 85mm x 85mm box

• arduino pro mini 3.3V clone
• SX1276 with spring antenna
• W5500 lite
• 5V 802.3at power over ethernet splitter (gutted)
• SPELSBERG IP55 box

So I ordered Arduino Uno for programming my Pro Minis. And going to experiment with 2xAA or 3xAA setup without step up booster (they are whining anyway so I will be happy if I get rid of it

Thank everyone for help!

So I ordered Arduino Uno for programming my Pro Minis. And going to experiment with 2xAA or 3xAA setup without step up booster (they are whining anyway so I will be happy if I get rid of it

Thank everyone for help!

@skywatch said in Battery Powered Sensors:

I think you will find that all the 'good stuff' from the low power library is included in mysensors sleep function anyway.

So when I use sleep() mysensors library overloads the generic arduino sleep?

I suggest using minicore (it is easy to install and all works from within the arduino IDE you are used to) and set internal oscillator and disable BoD. You will need a programmer (a few dollars) or you can use another arduino as programmer. but that is more time consuming to set up and easier to mess up as well!

I look at the git repo and I more confused now. I thought it is some kind of bootloader/firmware I flash. What is Arduino core? I never heard that term.

Good that you got rid of the booster!

I wonder why the booster is recommended here https://www.mysensors.org/build/battery ? Or did I misinterpreted?

@tssk said in Battery Powered Sensors:

I removed the step up booster connected + directly to VCC but the node stopped working - only the arduino onboard led is constantly on.

The problem was that the batteries I used were not completely fresh. I googled that Arduino pro mini need at least 2.7V to operate. Using fresh batteries the node is working. And it shows 6.0mA in sleep and 25.4mA when transmitting.

So using the stepup booster adds 6.5mA in sleep and 65mA when transmitting to consumption?

I also found LowPower library (https://github.com/rocketscream/Low-Power) but it seems to interfere with mysensors library (https://github.com/rocketscream/Low-Power/issues/80). Any experience?

andreas-bulling created this issue in rocketscream/Low-Power

open Compile problem: multiple definition of `__vector_6' #80

I removed the step up booster connected + directly to VCC but the node stopped working - only the arduino onboard led is constantly on.

I also tried to measure the step up booster alone and it is showing 0.05 at 20mA on multimeter settings.

I am now really confused and I am not sure what to conclude from that...

I hope I am measuring it correctly.

It shows 12.5 when in sleep and up to 90 when transmitting/measuring.

Any one can interpret that for me please?

@TheoL I see so you measure every tim e but send only sometimes. Nice idea thanks.

@skywatch

• This is room sensor and I would like to react to changes in temperature and airquality - I was thinking that I could prolong the interval up to 12min. What do you think is optimal measurements rate for room thermostat?

• Is it possible / necessary to put the radio module to sleep? How to do that?

• So far I did not mess with the Arduino bootloader but I would like to Any link that I could read about it? And specifically about the minicore you mention?

• I do not understand what you mean by the pull-up resistors?

• I have my node in the middle of the room around 20-24C that sould not be the problem. Actually it is it main purpose to provide data for optimal room temperature.

• I included step up boosted based on recommendation on the https://www.mysensors.org/build/battery page. I thought it should use the batteries most efficiently. I think I could go with 3 AA batteries. Will I need to regulate the voltage or can I power the radio and bme modules directly?

@mfalkvidd

• I did not know that I need to turn BME off ů how to do that?

• Only thing I found is that Arduino has deepSleep() - but I am not sure if I can use it.

• I am using the default Bw125Cr45Sf128 but thinking about testing Bw125Cr48Sf4096 to achieve greater range.

• Booster is the whining one - https://www.laskarduino.cz/step-up-boost-menic-s-me2108-33v-480ma/

• Is there a way I can measure power draw with multimeter?

// Enable debug prints
//#define MY_DEBUG

// Enable passive mode
#define MY_PASSIVE_NODE

// Passive mode requires static node ID
#define MY_NODE_ID 100

// Enable and select radio type attached
//#define MY_RADIO_RF24
//#define MY_RADIO_NRF5_ESB
//#define MY_RADIO_RFM69
#define MY_RADIO_RFM95

//#define MY_DEBUG_VERBOSE_RFM95
#define MY_RFM95_FREQUENCY (RFM95_868MHZ)
//#define MY_RFM95_MODEM_CONFIGRUATION RFM95_BW31_25CR48SF512
#define MY_RFM95_CS_PIN 8
#define MY_RFM95_IRQ_PIN 2

#include <MySensors.h>
#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include "Adafruit_BME680.h"

#define BME_SCK 13
#define BME_MISO 12
#define BME_MOSI 11
#define BME_CS 10

//#define SEALEVELPRESSURE_HPA (1013.25)

// Initialize general message
MyMessage msgTemp( 1, V_TEMP );
MyMessage msgHumi( 2, V_HUM );
MyMessage msgAirq( 3, V_LEVEL );

//Adafruit_BME680 bme; // I2C
Adafruit_BME680 bme(BME_CS); // hardware SPI
//Adafruit_BME680 bme(BME_CS, BME_MOSI, BME_MISO,  BME_SCK);

void setup()
{
  analogReference(INTERNAL);

  if (!bme.begin()) {
    Serial.println( "ERR: BME680 not found" );
    while (1);
  }
  // Set up oversampling and filter initialization
  bme.setTemperatureOversampling(BME680_OS_8X);
  //bme.setPressureOversampling(BME680_OS_4X);
  bme.setHumidityOversampling(BME680_OS_2X);
  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
  bme.setGasHeater(320, 150); // 320*C for 150 ms

  delay(2000);
  
}

void presentation()
{
	// Send the sketch version information to the gateway and controller
	sendSketchInfo("Room sensor", "4.0");

	// Register all sensors to gw (they will be created as child devices)
  wait(100);
	present( 1, S_TEMP );
  wait(100);
  present( 2, S_HUM );
  wait(100);
  present( 3, S_AIR_QUALITY );

}

void loop()
{

  int batt = analogRead( A3 );
  // 1M, 470K divider across battery and using internal ADC ref of 1.1V
  // Sense point is bypassed with 0.1 uF cap to reduce noise at that point
  // ((1e6+470e3)/470e3)*1.1 = Vmax = 3.44 Volts
  // 3.44/1023 = Volts per bit = 0.003363075
  int battP = batt / 10;
  #ifdef MY_DEBUG
      float battV  = batt * 0.003363075;
      Serial.print( "Battery Voltage: " );
      Serial.print( battV );
      Serial.println(" V");
      Serial.print( "Battery percent: " );
      Serial.print( battP );
      Serial.println(" %");
  #endif
  wait(100);
  sendBatteryLevel( battP );
  

  if (! bme.performReading()) {
    Serial.println( "ERR: BME680 reading failed" );
    return;
  }
  
  float temp = bme.temperature;
  #ifdef MY_DEBUG
    Serial.print( "DBG: Temperature = " );
    Serial.print( temp );
    Serial.println( " C" );
  #endif
  wait(100);
  send(msgTemp.set( temp, 2 ));
  
  /*
  float pres = bme.pressure/100.00;
  #ifdef MY_DEBUG
    Serial.print( "DBG: Pressure = " );
    Serial.print( pres );
    Serial.println( " hPa" );
  #endif
  wait(100);
  send(msgPres.set(pres,2));
  */
  
  float humi = bme.humidity;
  #ifdef MY_DEBUG
    Serial.print( "DBG: Humidity = " );
    Serial.print( humi );
    Serial.println( " %" );
  #endif
  wait(100);
  send(msgHumi.set( humi, 2 ));
  
  /*
  float alti = bme.readAltitude(SEALEVELPRESSURE_HPA);
  #ifdef MY_DEBUG
    Serial.print( "DBG: Approx. Altitude = " );
    Serial.print( alti );
    Serial.println( " m" );
  #endif
  wait(100);
  send(msgPosi.set(alti,2));
  */

  float airq = bme.gas_resistance / 1000.0;
  #ifdef MY_DEBUG
    Serial.print("DBG: Gas Resistance = ");
    Serial.print( gas );
    Serial.println(" KOhms");
  #endif
  wait(100);
  send(msgAirq.set( airq, 2 ));
  
  
  sleep(10000);
	//sleep(180000);
}

Hello

I would like to ask for help with passive battery powered node I created with following components:

• Arduino pro mini 8MHz - voltage regulator and power LED removed
• SX1276 based 868MHz LoRa radio
• BME680 sensor
• DC-DC 3.3V step-up booster

I created a battery measuring circuit according to scheme on this page ( https://www.mysensors.org/build/battery ).

The problem is the two fresh new AA batteries lasted less than 14 days and stopped when the circuit measured 36%.

2x1.5V AA Aerocell following start and end values:

09.02.2021 16:45 102% (start) : 1.610V and 1.610V
22.02.2021 04:15 36% (end) : 1.001V and -0.150V

The node code is sleeping for 6 minutes between each sensing and sending data.

sleep(180000);

14 days seems very short to me. Is that normal? Is there something I can to make it last longer?

Thanks