[SOLVED] Counter IC does not count

Thread Starter

gelzky

Joined Dec 7, 2021
86
Hello hope you can help me finish my logic circuit. I'm trying to make a circuit that counts people and when it reached 19 it will alarm. I'm using counter IC 4026, Xor gate, ir sensor module and a bcd 7 segment display. The sensor seems to be working but the counter does not change the display its only 0. I just followed some yt video in making this. ANd I'm planning to add a buzzer that will alarm when the counter reached 10.

Mod: lightened your image.E
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Ian0

Joined Aug 7, 2020
4,895
Do you have a PULL DOWN resistor on RESET?
Does your optical sensor need a PULL UP resistor to Vcc? Many of them have open-collector outputs.
 

Thread Starter

gelzky

Joined Dec 7, 2021
86
Do you have a PULL DOWN resistor on RESET?
Does your optical sensor need a PULL UP resistor to Vcc? Many of them have open-collector outputs.
yes, I just added it tho the counter still does not work. what do you mean by open-collector outputs.
 

ericgibbs

Joined Jan 29, 2010
15,378
hi g,
OK,
It looks OK, compare it to this diagram.
Have you checked the signal is actually coming out of the sensor.?
E

Don't get distracted regarding open collector outputs.
 

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Thread Starter

gelzky

Joined Dec 7, 2021
86
hi g,
OK,
It looks OK, compare it to this diagram.
Have you checked the signal is actually coming out of the sensor.?
E

Don't get distracted regarding open collector outputs.
yes the sensor lights up including the led when i pass something through it. I don't know what really the problem is
 

ericgibbs

Joined Jan 29, 2010
15,378
hi g,
Ok,
Look at the circuit I posted, add the Clock push button, then try clocking the 4026 that way to prove that part of the circuit, [ disconnect the sensor]
E
 

ericgibbs

Joined Jan 29, 2010
15,378
hi g,
Are you saying it is counting with push buttons.?
E
Edit: is the 4026 circuit wired as the circuit I posted.?


Pin #5 should not be grounded it is the carry out pin.

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ericgibbs

Joined Jan 29, 2010
15,378
hi,
Pin #5 would go to the next 4026 Clock input if you were using two 7 segment display to count to 99.

If that simple circuit using two push buttons does not work, Clock and Reset then check your wiring and 4026 IC.

Those push buttons can easily be connected the wrong way around, make sure when they are pressed that pins #1 Clock goes High, use a voltmeter to measure pin #1. Do the same for pin #15 Reset.

E

Check this video.
https://components101.com/ics/ic-cd4026-pinout-circuit-datasheet
 
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Thread Starter

gelzky

Joined Dec 7, 2021
86
hi,
Pin #5 would go to the next 4026 Clock input if you were using two 7 segment display to count to 99.

If that simple circuit using two push buttons does not work, Clock and Reset then check your wiring and 4026 IC.

Those push buttons can easily be connected the wrong way around, make sure when they are pressed that pins #1 Clock goes High, use a voltmeter to measure pin #1. Do the same for pin #15 Reset.

E

Check this video.
https://components101.com/ics/ic-cd4026-pinout-circuit-datasheet
that worked!:>>> tysm! i tried to check the push buttons' output using led then it fixes it now the 7 segment counts. tho I tried to connect the sensor back but it does not count again? help me pls :>>>
 

ericgibbs

Joined Jan 29, 2010
15,378
hi g,
That's great, at least you know the 4026/LED is now working.:)

Try this, connect the sensor to the input pin #1 of the 4026, measure with a voltmeter the voltage on pin #1 while you move your hand about in front of the sensor, what voltage do you measure.?

E
 
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