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7 segment display

Springcone710

Dec 16, 2013
4
Joined
Dec 16, 2013
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4
Hi,

I'm wanting to build a simple lap counter for my nephews scalextrics! I want it to be as simple as possible and if I can, I would prefer not to use adruino!

Does anyone know if it's possible to make the 7 segment display count up and cycle back to 0 with just 1 switch? If so, how?

I want to put the snap action switch in the groove on the scalextrics so that when the car passes the start/finish line, the cars leg that fits in the groove will press the switch and the 7 segment display will change!

Thanks, chris
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,505
Joined
Jan 21, 2010
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25,505
Fairly simply, you could connect a counter with a bcd output to a bcd to seven segment decoder, and that to a seven segment display.

The switch generates the clock signal which increments the counter. You'd probably wire up the reset line so you could push a button to reset the counter(s).

The main problem is the switch. Switches bounce, so you would need to de-bounce it so that each press generated just on clock pulse, and therefore just increments the counter by 1.

Chips you might be looking at are a 40106 (hex schmitt trigger) to be part of a circuit to debounce the switches, a 4511 BCD to 7 segment decoder/driver, and a 4510 BCD up/down counter.

The use of a BCD counter eliminates problems with values 10 to 15 which can't be displayed on a single digit. This also allows you to cascade them for 2 or more digits.

Oh, note that you need common cathode displays.
 

ziin

Dec 2, 2013
9
Joined
Dec 2, 2013
Messages
9
It depends on what chip you prefer to use? Two of my favorite chips are Microchip and Arduino.

If you want to use Microchip, I can give you more advice.
 
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