One of the two digit 7segment display will read its values from a smoke sensor while the other will read its values from a temperature sensor. From what I have seen in textbooks recently;each segment display will make use of ten digital pins(7 segments, decimal point, display faces(correct me if I'm wrong Pls)).

  • You could connect the segments of the two displays to the same Arduino pins, so you only need two additional pins for the second display. You then multiplex over the four digits instead of the previous two.
    – Gerben
    May 31, 2017 at 8:13

1 Answer 1


You are correct about the 10 pins, shift register are probably the way to go for you. They are very cheap and pretty simple to use. Try googling 74hc595. It basicly turns 3 pins into 8, and you can even Daisy chain the chips to get 16, 24, 32 and so on from the 3 pins on the arduino. Good luck to you.

  • This is one way to do it, but you can do it without any extra hardware, as explained in the question/answer I linked to.
    – Mark Smith
    May 31, 2017 at 8:32
  • Well that's a brilliant solution! I suggest trying marks link before my solution. 😊
    – de_rush
    May 31, 2017 at 8:36

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