KM digital stepcounter

[sohanphilip]

https://www.redcircuits.com/Page9.htm

ckt will be found here

...the problem is only the decimal point of d1 is illuminting and switchin off alternately after 32 cycles ..display is always showin zero zero even after hundreds of steps...i have given the voltage as 3volts...

 

[duffy]

The decimal on D1 is wired to the output of the ripple counter, so it is suppose to switch on and off like that when the "display" button is held and you are walking. So, this tells you the input circuit is working, it is counting pulses from the mercury switch. So far so good. The problem seems to be that the 4026 counters are not counting. Check the wiring - in particular pins 1, 2 and 15 on IC3 (you know the others work if you see "00"). Also make sure the "reset" switch is open (low on pin 15 IC3).

 

[sohanphilip]

the pin 11 of 4093 is fed toi pin 1 of 4026.......its producing 0.9-1.0volt continously for 32 cycles of mercury switch...for the next 32 cycles its 0 volt.....but still both the displays are showin 0 and 0...the battery voltage is around 2.9 volt.......

 

[duffy]

.9-1V is too low. The 4021 needs closer to 2V to be able to tell "1" from "0". The 4093 should be able to give nearly the full 3V. Try disconnecting everything from pin 11 on the 4093 and see if it goes up to the full 3V.

 

[sohanphilip]

i think u r refferin to 4026 (i m not usin 4021)....shall i give the output of pin 11 of 4093 to a scmitt trigger so tat it can give 2 volt so tat 4026 can count it

 

[duffy]

Yes, 4026, sorry. The 4093 should be able to give the full 3V, disconnect pin 11 to see if something is loading it down.

 

[sohanphilip]

thank u very much for the reply but can i give it to a scmiit trigger before givin it 4026??

 

[duffy]

A schmitt trigger is more demanding on the input voltage swing. You should to find out why you are only getting 1V instead of 3V, this indicates there may be a bigger problem.

 

[sohanphilip]

u were absolutely right!i checked it was overloaded! so i eliminated the fuctionality of tat decimal point which had a period of 32 cycles...the output of pin 9 of 4093 was directly fed to pin pin 1 of 4026 so i got 3v...then it worked!!!!

THANK U VERY MUCH MR.DUFFY

 

[duffy]

Sure!