Dear Instructables, how would i go about creating a 3 digit up counter that reacted to 3 buttons of different values?

Basically i'm designing and making a scoreboard for a rugby match for an a-level course. I'll explain the buttons of different values first, in rugby (for those who don't know) there are 3 different ways that the score can increase 2 points (conversion), 3 points (penalty, drop goal) and 5 points (try). I already know how to make a circuit to increase in 1's but i wasn't sure if you could do it with 3 different values in the same circuit. I was thinking of using a 4024 seven bit counter connected to a bcd to led decoder then to 7 segment led displays. is there anything out there which could make my job easier or do you have any advice or could you help me? Thanks alot, Hrimiller
Edit: 4024 seven bit counter connected to a bcd to led decoder then to 7 segment led displays

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frollard4 years ago
If you REALLY want to go the integrated circuit method -- you already know how to have an up/down counter increment by ones - you can do a few things.

You could use a binary addition circuit to add the binary score to the binary new points value, each button could apply the voltages through diodes to the correct bits during the add process.

You could make a counter out of an astable 555 and a 4017 decade counter (one on each button) such that one press causes x pulses to go into your single counter circuit.

Or, for versatility, my recommendation would be to go the microcontroller route. A $10 teensy or arduino, or pic, etc could do a bajillion features - all the buttons you could imagine, counting up, down, timer, dedicated 1 3 5 point buttons, etc.
hrimiller (author)  frollard4 years ago
Thanks for the reply, very useful! how would i go about creating an astable that pulses 2, 3 or 5 times?
Also i realised that i had made a mistake when i was writing up the question. I am actually using 4024 seven bit counters connected to BCD to LED decoders. Thanks alot, Hrimiller
Either way,

The way I would do it (again, if not using a microcontroller, which I would)...

Theoretically, in my head it can use some of the same parts - a few flip flop latches with separate reset lines (you'd have to look up a circuit to do this)
You would need something like an astable 555 that latches 'on' and oscillates rather quickly at the push of a button, incrementing a 4017 decade counter. The latch also allows the 555 timer pulse to go to the total point counter to increment the score. When the 4017 gets to the desired number of points, it disables the latch for that button/score and stops the 555 timer, also resetting itself. The 3 different point values could be each their own latch circuit, hooked to a different output on the same 4017 counter. The only way you run into trouble is if more than one button is pressed at once...which might work (counting to the first value, turning off, then counting to the second value). You also need latches that unlatch even if you hold the button down.

So, a pile of transistors, lots of diodes, and a few ics...and a tonne of soldering on perfboard.

...or get a teensy and be done with it :)
Arduino would also give you an easier way to undo the last increment.. (Pushing 3 instead of 1)
that's what I said, dedicated buttons for ANY feature you can imagine.
lemonie4 years ago
Why don't you like the idea of pushing a button 2, 3 or 5 times?