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I need, for a project, to connect on the same RPi (a 3B+) a NFC lector, the Sense Hat and also be able to use 26 GPIO port for additionnal LED and button. The project is a kind of a physical "Keep Talking And Nobody Explode".

I wanted to know if it's possible to stack the hats and be able to use the GPIO port, or if I need an additionnal chip to "add" more port.

(btw i'm French, I appologise for potential error)

RλPHλΣʟ
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    what GPIOs are available depends on what GPIOs the NFC and sense hat use - since they both seem to be able to use i2c (so, 2 GPIO in total, since both devices can be controlled on the same i2c bus), seems like you'd have plenty of GPIO available - not sure if it's 26 though – Jaromanda X Feb 25 '20 at 21:36
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    of the 40 pins, 12 are power/ground and you'd need 2 for i2c for the two hats - that leaves exactly 26 GPIO pins, but I'm not sure all these pins could be used, pretty sure some have fairly specific functions - also, the NFC hat would sit on top of the sense hat, making the sense hat inaccessible ... or, the sense hat on top of the nfc hat, making the nfc hat inaccessible – Jaromanda X Feb 25 '20 at 21:39
  • Yes, stackable HATs: https://raspberrypi.stackexchange.com/questions/104705/how-to-tap-tee-fork-the-rpi-gpio-pins-covered-blocked-by-a-hat-phat-bo – tlfong01 Feb 26 '20 at 00:59

1 Answers1

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I wanted to know if it's possible to stack the hats

Depends on the HAT - the Sense HAT exposes pins BUT putting another HAT on top would make it unusable. Some have stackable headers but not all.

The Pi exposes GPIO 0-27, of which 0,1 are reserved - leaving 26.

The Sense HAT uses some of the pins https://pinout.xyz/pinout/sense_hat so not all are available.

Milliways
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