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  • The battery I pictured above has that same (JST PHR2) connector, and says 3.6v. Would that one work then?

    Yes, it'd be fine.

    If the battery is fully charged (and is above 3.6v), could that break (burn) the espruino? Should I get a voltmeter to check before wiring it up?

    Only if you are going to wire it up as @allObjects had suggested - if you do as in my post then you don't need to worry about the voltages (as long as the battery isn't much over 5v!).

    If I get that battery, would the white JST PHR2 connector fit onto the GND/VUSB pins directly?

    Unfortunately not - the pin spacing is different. You might be able to bend pins and force it but I'd suggest a separate connector if possible (you can always buy the socket quite cheaply and then solder that direct to the pins).

    Battery Black -> Espruino GND -> LM3671 GND
    Would I need to fork the black wire to two wires (like a snake tongue) and connect to both pins, one on each board?

    Yes - it doesn't matter how you do it though - you could use one long bit of wire and strip the insulation in the middle if you wanted.

    LM3671 3V -> Espruino 3.3v
    Just to confirm, this is to the 3.3v pin (which the schematic calls "3.3v output"), NOT the VUSB pin?

    Yes, that's the one!

    Just to add though - the USB power pack idea is easy, cheap, and tidy, and it'll easily run the Espruino WiFi for far more than a day, which would probably be enough for you?

  • Thr 2017.06.01

    From #14
    Thank you @allObjects for the datasheets and detailed analysis.

    From #21
    @trusktr after consideration of your project requirements, the suggestion that Gordon made of using a USB power pack makes more sense for the demo, my suggestion for the power adaptor (I use a Kindle charger) should you have one lying around or for long term power on requirements

    From #19

    Just to confirm, this is to the 3.3v pin (which the schematic calls "3.3v output"), NOT the VUSB pin?

    As @trusktr had the same question, would @Gordon please expound on the following to add clarification for us all:

    It is given that: (links found in #2 above)

    • The schematic at github shows that there is a VBUS [ J2-2 ] and a VUSB
    • The regulator shows an input of 5v but isn't clear on it's origin (after Fuse F1 perhaps)
    • EspruinoWiFi documentation explains that the 3.3v pin [ J2-3 ] is an output
    • There is a stern warning not to connect VBUS [ J2-2 ] when the micro USB connector is attached

    Q1: Was this distinction VBUS vs VUSB made for schematic software reasons and not a typo?

    Q2: What/Where is the connector showing VUSB/DM/DP or is this the input to the WiFi module?

    Q3: Under the assumption the micro USB connector is feeding the power, is it true that VBUS [ J2-2 ] is available as an output and that it is electrically connected to the input (after Fuse F1 perhaps) of the regulator as 5v (the source a USB port supplies), and therefore also supplying 3.3v as VDD [ J2-3 ] as an output?

    Q4: Under the assumption that supplemental power from a 3.3v battery is supplied, and that no micro USB connector is attached, that is could be applied as an input VDD at [ J2-3 ] bypassing the onboard regulator?
    Note: This would mean there is no fuse protection and that input voltage would not be detectable at PA9/P30

    Q5: Similarly as above, upto 5v could be supplied by a regulated supply to VBUS [ J2-2 ], thus using the onboard voltage regulator, producing the 3.3v to the rest of the circuitry, and at VDD [ J2-3 ] as an output?

    Thank you Gordon

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