currently I am working with the Raspberry Pi Zero W to build a UPS. Therefore I bought the UPS hat from Pi Supply.

Nevertheless, I have to use 2 Pins for my measurments with the JSN-SR04T-3.0.

Which pins are used for the UPS hat? All? Haven't found any datasheet which offers this information.

  • 2
    keep looking for the datasheet or examine the UPS hat
    – jsotola
    Nov 6, 2020 at 20:22
  • 1
    Why not ask Pi Supply?
    – CoderMike
    Nov 6, 2020 at 22:25
  • @CoderMike I will :D
    – kaulex
    Nov 7, 2020 at 12:27

1 Answer 1


WARNING Though the numbers below match the PIN numbers on the published PDF they DO NOT match the numbers normally shown for the Pi. e.g. 5V is on 2 and 4 normally.

Normally I would send you to the great documentation site pinout.xyz for details BUT in this case, the only Pi-Supply board is the full sized hat for the Pi-Juice board.

Fortunately they do publish a schematic on GitHub BUT it is three years old, for version 1.1 of the PiJuiceTop and may not match your board.

Looking on that you can see the board documented (i.e. it may not match yours) uses:

See warning above on these numbers

Ground on pins 5,13,19,29,33,10,26,40. (odd given they are all common on the Pi board).

3v3 on 18

5v on 1,3

ID SCL and ID_SD on 27, 28 (to tell the Pi it is the UPS card)

SDA 1 / SCL 1 on 4,6

TBH - I would go back to the suppliers and ask for confirmation this is still valid.

A QUICK scan of the GUI source shows line 34 interrogating address 0x14 on I2C Bus 1 to see if anything is there and that matches the hardware diagram. I'll let you decode the core operating function PiJuice if you want more info :-)

  • Note I've opened an issue for this numbering github.com/PiSupply/PiJuice/issues/576
    – user115418
    Nov 7, 2020 at 5:29
  • Nice. Thank you for the detailed awnser! I stumbled also across the problem that something with the pin mapping is not correct because the board is generally not working correct. (i.e. 90 degree on battery which is obviously false) I will check everthing and awnser you later :D
    – kaulex
    Nov 7, 2020 at 11:50

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