ATMega328p 8Mhz internal, standalone, mysensors low power problem

  • Hi ! I have started to upgrade mysensors ( 1.5 ) thats been working for a long time to version 2.1.1 but can't seem to get lowpower working.

    Tried most of the stuff out there like different bootloaders and changing NRF24 chips but I end up with 17mA during transmit and between 2,4 - 3,5mA in sleep mode.

    Tried using other low power libraries like which works nice but is not compatible with mysensors because some parts are already implemented there I guess. With this library I get sleep mode like 20uA but then again can't get mysensors to work. What's the catch ?

    Anyone else have this problem and hopefully a solution for standalone ATMega 328p ?

  • Hero Member

    @torfinn I cannot reproduce this. Can you post your sketch?

  • @AWI

    Here is a minimal sketch I am testing with:

    #define MY_RADIO_NRF24
    #include <SPI.h>
    #include <MySensors.h>  
    #include <DHT.h>
    #define DHT_DATA_PIN 8
    #define SENSOR_TEMP_OFFSET 0
    static const uint64_t UPDATE_INTERVAL = 60000;
    #define CHILD_ID_HUM 0
    #define CHILD_ID_TEMP 1
    MyMessage msgHum(CHILD_ID_HUM, V_HUM);
    MyMessage msgTemp(CHILD_ID_TEMP, V_TEMP);
    DHT dht;
    void presentation()  
      sendSketchInfo("TemperatureAndHumidity", "2.2");
      present(CHILD_ID_HUM, S_HUM);
      present(CHILD_ID_TEMP, S_TEMP);
    void setup()
    void loop()      
      float temperature = dht.getTemperature();
      float humidity = dht.getHumidity();
      send(msgHum.set(humidity, 1));

  • Hero Member

    @torfinn nothing wrong with your sketch it should do the trick. Are you sure it worked with low consumption in v1.5?
    (p.s. I put the sketch in your post between code marks for better reading) 0_1490256228810_upload-e508ae50-3ab8-4f21-872d-31cd6ee9f282

  • I have 4 sensors (temp/hum and contact switch) powered by 3V coin battery and with the library 1.5.4 they run for a year. I also decided to upgrade them to the library 2.1.1 and I got some issues. For example the binarysqwitchsleepsensor doesn't sleep. I also noticed that the initialization has many messages sending failure and that is a heavy blow for the battery, I went back to the 1.5.4.

  • Hero Member

    @mortommy that explains something. The 2.x version is more strict in guaranteeing communication is working. There are some tricks to get around it.

  • Thank's for your feedback.

    Did you use the usual gw.sleep command on 1.5.4 or any other lowpower libraries ?

  • Could it be board related ? I am using Arduino 1.8.1. I tried compiling with Ardino Pro / ATmega 328p 8Mhz as stock setup and now using both bootloader and setup from here:

    I was just thinking that maybe some of the command in the mysensors library are disabled if it detects another board setting ?

    Also anyone know if the pin 2 / IRQ should be used ? Its not connected in my project could it be that mysensors is awakened by this ?

  • @torfinn RESOLVED:
    Hi ! I had problem with properly registering on the gateway ( due to chips was used on old version earlier ). After finding this post I tried the and it fixed problem. Looking at 40uA sleeping now 🙂

  • @mortommy Hi ! I decided to go with 2.1.1 on new sensors but still have the old 1.5.4 gw running. Had to change frequency to #define MY_RF24_CHANNEL 125 as the 2.1.1 sensors also registered partialy ( temp not humidity ) on the old 1.5 gw.

    Also tried out #define MY_REPEATER_FEATURE Disabled this seems to do the opposite what i thought. Radio is never turned off ie. 17mA drain.

    Added the following to try the lower the init etc. and it improves a little.
    #define MY_REGISTRATION_FEATURE Disabled

    I think its a serious flaw that if the gw for any case locks up our sensors will drain the battery until it's back online again.

  • Admin

    @torfinn said in ATMega328p 8Mhz internal, standalone, mysensors low power problem:

    #define MY_REGISTRATION_FEATURE Disabled

    This has no effect, the correct approach would be to comment this line:

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