External battery for Puck.js?

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  • Hi at all!

    Is it possible to power the Puck.js with an external battery as well as the MDBT42Q breakout board?

    Puck.js has a voltage regulator?

    Thanks in advance

  • You can power Puck.js from an external battery - either from the 0.1"/2mm pins on the board (3v and GND) or by using a 'fake' CR2032.

    However there is no voltage regulator so your voltage should be between 2v and 3.6v. That means you can't directly connect a LiPo.

    You can however:

    • Connect a LiPo via a diode to drop the voltage
    • Connect to 2xAA or AAA batteries
    • Connect to a non-rechargeable lithium battery
    • Connect to a LiFePo4 battery

    Hope that helps!

  • @Gordon thanks for answering so quickly.

    I am developing a project that will be connected by BLE continuously. That's why I need additional power to the CR2032. I will opt for MDBT42Q breakout board.

  • Ok, great.

    It's worth noting that with any recent firmware (2v01 and later I think) all Espruino devices will go to a lower-power connection mode (200ms connection interval vs 7.5ms) when connected by idle for around a minute - so you should find that it's not actually using significantly more power than if it was just sitting there advertising.

    You can tweak what happens with the connection using NRF.setConnectionInterval - so if you need the speed all the time you can still tell Espruino to do that.

  • @Gordon thanks for the clarification.

    This project is for an installation embarked on trains and only the button will be visible, all the electronics will be hidden under a panel of difficult access. Therefore, replacing the battery can only be done once or twice a year.

    My idea is to attach a battery that feeds the main power when the train is off.

    Could you recommend some battery and intelligent power board that allows to use an external power (power supply) and when it is missing, switch to a battery?


  • Ok, great.

    Honestly, I'd just use a big non-rechargeable lithium battery. If you use an AA format non-rechargeable lithium you're looking at ~2500mAh and often a 10 year life: https://uk.farnell.com/c/batteries-chargĀ­ers/batteries-non-rechargeable?battery-vĀ­oltage=3.6v

    Then I'd just attach it to the 3.3v rail of the MDBT42Q breakout board with a diode. That way if the 3.3v rail ever drops (because the voltage source powering it fails) then the battery will take up the slack, but it won't be powering it normally.

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External battery for Puck.js?

Posted by Avatar for migsanvi @migsanvi