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Topic: 4 digit display with keypad (Read 740 times) previous topic - next topic


Basically, using the 4 digit 7 segment tm1637 module and 4*4 matrix keypad.

I want to be able to type numbers on keypad, and the display will continue showing till 4th number. When I press * or #, it should clear the display. Now with the "A", "B" ,"C", "D" keys, I want a pin to pull high when I press "A" , when I press "B" pull low "A" 's pin and pull high another pin for B (4 Letters like a selector switch, to control a relay).

Could someone type the code for me please?


Could someone type the code for me please?
type which code?

did you mean invent the code and develop that for you?
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Hu IY3775,

That's pretty straightforward, but you'll need to work out some of the details.

A few questions for you:

1. What does "displaying until the 4 th number" mean?  Do you want the display to clear or lock in the number?

2. What should the sketch when it receives a 5th digit? It's already displaying 4, should it ignore it or shift the displayed number, i.e., 1234 displays "1234" and pressing 5 displays "2345"?

3. What happens when the 4th digit is entered? Are you comparing it to an expected code or does the number get used in some other way?

4. I assume the A-D buttons work independently from the others and won't intetf with the numeric sequence.

There are 10 types of people in the world, those who understand binary, and those that don't.


Seems pretty straight forward. Key code and relay activation.
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They always seem simple till you talk to the user about the real requirements.

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