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Hi I want to ask a question about my graduation project in universty.I desing electronic metronome? Answered

I use 8 led and it will count 1-2-3-4-5-6-7-8-7-6-5-4-3-2-1-2-3... ıt goes like this but when I desing it,it count 1-2-1-2-3-4-5-6-7-8-1-2-1-2-3-4-5-6-7-8... like this.I use r-555(timer),4510 up/down counter,74ls138.And it will tempo adaggio,moderato,andante,allegro.I mean ıt should give 4 italian tempo...

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steveastrouk (author)2012-01-02

Nothing like accurate enough with a 555 timer - and this is a graduation project ????

Yohu need to use a microcontroller, or a CPLD.

Steve

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eraygau (author)steveastrouk2012-01-03

I desinged circuit but my counter is going 0-1-2-3-4-5-6-7-8-9-8-7-6-5-4-3-2-0-1-2-3....... ıt count like this.But I use 3-8 decoder so its output 8 but my counter gives 10 output so I dont solve this problem

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eraygau (author)steveastrouk2012-01-03

http://a1201.hizliresim.com/t/4/1knzj.png

This is my project desing and when I run the multism,it s ok .But real it doesent run.I controlled every connection and everything is ok .I thinks my problem is about counter.Because ıt  count 1-2-3-4-5-6-7-8-9-8-7-6-5-4-3-2-1-2-3..... it goes like this.But I use 8 leght.So it can not send a signal turue.My desing goes like this 1-2-1-2-3-4-5-6-7-8-1-2-1-2-3-4-5-6-7-8-1-2.... but I want 1-2-3-4-5-6-7-8-7-6-5-4-3-2-1-2-3-4-5-6-7-8-7-6-5-4-3-2-1....It is very important for me ı must desing and I should run it thanks for your helping.

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steveastrouk (author)eraygau2012-01-04

This a lesson: SIMULATION IS NOT REALITY.

NEVER, EVER TRUST A SIMULATION.

Your problem is your counter, you haven't tied all the unused pins to safe states and noise is getting in. Your circuit has NO noise filter capacitors.

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eraygau (author)steveastrouk2012-01-04

I know it but how I can correct it Noise filter capacitor ı used in realty it not problem but ı Will change or correct to counter.My problem is counter I suppose that if I used 4x16 decoder it will be ok ...

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steveastrouk (author)eraygau2012-01-04

TIE ALL YOUR UNUSED LINES TO THE COUNTER APPROPRIATELY. There is nothing WRONG with the counter, its picking up noise.

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eraygau (author)steveastrouk2012-01-04

I changed my decoder 4 to 16 it count 1-2-3-4-5-6-7-8-9-10-1-2-3-4-5-6-7-8-9-10... but it dosent count back how can I do it can yo help me ?

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