rkgoyal_98
New Member
Dear Seniors,
Electronics Circuits is my hobby. I am looking for a project to bulid a countdown/ countup timer. Timer should be able to energise a relay after predifined time say 6 minutes and should keep on displaying the remaining/elasped time. I can do with either countdown or countup timer.
While searching the Net is have come accross following designs
Count-down timer
However since programming was not possible as such i could not go ahead with this project.
I have come accross another circuit at this link and have designed the same
Circuit drawing of Count-down timer
However i have finished the project there is error, and the when i set bcd switch for required time the output displayed is random and not matching the BCD set time.
Kindly advise what can be reason for the same. I have also tried to disconnect pins 4, 13 and 11 from unit minutes place and then display on the LED segment is correct but when i attach pin 4, 13 and 11 the display in minutes units is random. Seconds place are working fine.
In order to simplyfy the project i have searched 4-digit counter (74C926)based deisgn in the datasheet.
**broken link removed**
However it is not clear if tens digit in seconds and minutes will be 59- after 00 or 99. There is a circuit available as digital stopwatch based on this chip but it is not yet clear. Can seniors through some light on this aspect. There is some mention in the data sheet that 74C927 with 10hz will show 9.59.9.
I have also come across ICM7217 based project.
**broken link removed**
however not yet sure if that IC is available in India and also what is required to be used for pulse. Kindly also advise how to integrate Relay in this circuit. I am not sure if Chip is avaiable in India as yet.
Regards
Electronics Circuits is my hobby. I am looking for a project to bulid a countdown/ countup timer. Timer should be able to energise a relay after predifined time say 6 minutes and should keep on displaying the remaining/elasped time. I can do with either countdown or countup timer.
While searching the Net is have come accross following designs
Count-down timer
However since programming was not possible as such i could not go ahead with this project.
I have come accross another circuit at this link and have designed the same
Circuit drawing of Count-down timer
However i have finished the project there is error, and the when i set bcd switch for required time the output displayed is random and not matching the BCD set time.
Kindly advise what can be reason for the same. I have also tried to disconnect pins 4, 13 and 11 from unit minutes place and then display on the LED segment is correct but when i attach pin 4, 13 and 11 the display in minutes units is random. Seconds place are working fine.
In order to simplyfy the project i have searched 4-digit counter (74C926)based deisgn in the datasheet.
**broken link removed**
However it is not clear if tens digit in seconds and minutes will be 59- after 00 or 99. There is a circuit available as digital stopwatch based on this chip but it is not yet clear. Can seniors through some light on this aspect. There is some mention in the data sheet that 74C927 with 10hz will show 9.59.9.
I have also come across ICM7217 based project.
**broken link removed**
however not yet sure if that IC is available in India and also what is required to be used for pulse. Kindly also advise how to integrate Relay in this circuit. I am not sure if Chip is avaiable in India as yet.
Regards
