How to run an Arduino for years on a battery (2021)

(makecademy.com)

56 points | by thunderbong 3 days ago

5 comments

  • _ache_ 34 minutes ago
    There is an obvious mistake in the include.

         #include <JeeLib.h;>
    
    And the library doesn't seems well documented and rather shady actually.

    What is the casino thing ? It looks like an abandoned project that got web squatted / Brandjacked.

  • icedrop 4 hours ago
    Are images loading for anyone else? Seem broken for me.
  • whatever1 2 hours ago
    Maybe there are specialized microcontrollers that just efficiently sleep and wake up other microcontrollers?
    • apple1417 29 minutes ago
      On one of the projects I worked on, I brought a PIC16 down to ~20nA - where our fancy meter only went down to 10nA precision. It was completely unnecessary, but I'm still quite proud of it.

      For more standard cases, the 43uA from the article is roughly the same order of magnitude you'll get from pretty much any micro in sleep mode, after doing your first pass low power optimisation. The stuff I normally work with gets about 10. The thing is just, most of the time, that's low enough already - for this project 2500mAh/43uA = 6 years of sleeping. The bigger factor is the current it consumes while awake - and that's where the Arduino's a bit of a letdown, the stuff I normally use is only in the order of 100uA while awake.

    • lpribis 37 minutes ago
      This functionality is commonly built in to the microcontroller itself. MSP430s, STM32s ATMegas, and many others have real time clock and gpio wakeup functionality, which effectively lets you power off almost the entire die until either a time period passes or a gpio changes state. Commonly you can do similar for more complex peripherals as well, eg power off the core until you receive a UART message, but typically this is not a full power down like RTC sleep as it requires some peripheral clocks to stay running.
    • guenthert 2 hours ago
      TI's MSP430 is well suited for low-power applications (sleep current less than one µA) and has a number of other interesting features. Chances are the run-time is then limited by the self-discharge rate of the battery.
    • fake-name 2 hours ago
      The ATmega328 (i.e. arduino without the garbage) is that microprocessor.

      It can sleep and only use ~66 microamps at 5V with the watchdog timer enabled. That's 330 microwatts. A 1000 mA lithium cell (3.6 watt-hours) could then run it for ~10909 hours, or 454 days (~1 1/3 years).

      Almost every microprocessor made these days has some sort of low-power sleep. The ATmega series aren't even particularly good at being low-power.

      Of course, you then realize the "arduino" is really just a badly designed development board for an atmega, and they went and used cheap voltage regulators that have an idle current consumption of > 1 mA, and give up on the whole project.

      • crocowhile 2 hours ago
        Arduino a poorly designed board is up there with the iPod being lame. Arduino was designed to be accessible and lower entry barriers and it became unrivaled for these purposes. If you want to have long lasting battery powered project you just power directly with 3.3v.
    • colechristensen 1 hour ago
  • ggm 4 hours ago
    running RF for wifi or BT or something may boost the budget a bit. Fixed point sampling capture would mean clock coordination which drifts. Sending a wake call to come out of low power states is what the old "Morse code" audible pulses of interference on radio in the GSM days were doing: making the higher cost digital signalling stack wake up.

    I think zigbee does stuff in this space. 6lowpan too.

    Put a wifi or bt shield on, battery will drop faster.

    If the led can blink a code, you could remote read it off a phone or something. Newton's did IR networking. The conference translation headsets use it too: the radiators for the signal get appreciably hot.

    • userbinator 3 hours ago
      Sending a wake call to come out of low power states is what the old "Morse code" audible pulses of interference on radio in the GSM days were doing

      No, that's the phone itself transmitting in its TDMA timeslots. https://en.wikipedia.org/wiki/Time-division_multiple_access#...

      • ggm 3 hours ago
        So I got the directionality wrong, but it did seem to presage a call event: you heard the distinctive tones before the ring.

        Would you agree it's part of the re-initialisation sequence, even if not directly caused by the transmission infra talking to the phone?

  • xmprt 2 hours ago
    I wonder how well this works in practice with a more complicated project. For example, if you have something that's usually sleeping but still needs access to wifi in order to send data and can also be woken up by another sensor in which case the loop isn't as simple. Throw in some threads running in parallel and it becomes much harder to manage. There are sleep modes that you can use for this but it's not as simple as this.