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Project tested and working perfectly

A very simple Digital countdown timer using 8051 and 7 segment displays. A perfect project for microcontroller starters.

Author has used BCD to 7-segment decoder for driving displays. each segment has its own decoder. so there is no multiplexing included for displays. Additionally there are 2 control switches one to Start/Pause and second to Reset the timer. There is a Buzzer added to indicate timer has expired.

The code for this project is written in assembly language. Timer 0 is used for 1 second timer delay. Code is written for a hardcode 10 minutes timer. So there is a lot of scope to expand this project according to your needs. You can take this project as a reference if you want to develop more on it.

The zip file includes code, schematic and proteus simulation file incase you want to try project before building it. Complete list of files in given below:

File List information:
1. Timer.asm - Assembly code for project.
2. timer.hex - Pre-assembled hex file.
3. Digital Countdown Timer.png - Schematic/circuit diagram
4. Digital Countdown Timer.DSN - Proteus simulation file
5. timersimulation.png - Simulation screenshot

Incase you have any doubts regarding this project please make use of forum: Rickey's World forum

Thanks to Prasad.K.Wagh (Kartikceleb) and his team for this contribution.

If you want to contribute your projects to website please email me at: contact[at]rickeyworld[dot]info

Tags Digital Countdown Timer7-segment countdown timer

94.57 kB





boy donald
27 Oct 2014: 15:17 PM
I want to ask , why when I try to change the time ( minute ) can not be executed . thank you .
29 Oct 2014: 00:57 AM
Dear sir, thanks before. i have some project urgent for my school and my project need this digital countdown timer using 7 segmen display. but your project only show ten minutes countdown, i need your help, can you show me more to change the minute or set the time manually. thank you, sorry for disturbing you. sorry for my bad english.
02 Nov 2014: 07:15 AM
You will need to make changes in the source as this is a static timer. For changeable timer you will also need to add keys and provision for timer storage.
boy donald
03 Nov 2014: 02:31 AM
thank you for replying. but the problem, I'm not too smart to add the key and change the terms of its time. i hope you can help my project, sory for my bad english.
03 Nov 2014: 04:48 AM
We cannot provide you ready code or something but we can help you implement it. You need to be a little smart to understand what we say and then implement. Please create a forum topic to get more help on this project. we cannot keep posting in comments area.
boy donald
03 Nov 2014: 11:15 AM
Thank you for your attention , now I begin to understand what you are saying.
01 May 2015: 06:42 AM
Hey I am mechanical eng student and I would like to make a countdown clock for my go-kart team but we need more digits , like MM,WW, DD, HH , mm , ss , ms (month , week , day , hour , minute , sec , milli sec) .. can anybody help and tell me to how make such thing in big scale ?
08 May 2015: 16:07 PM
@shaygan, Please post your question in forum. Thanks!
15 Jul 2015: 13:40 PM
Hello Sir.... Do you have the report for the Digital countdown timer?
20 Jul 2015: 04:44 AM
@Ashna If its not available in the ZIP file then we don't have it either. Whatever is submitted by the Author is uploaded here.
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Thu Jun 11 2020, 06:27 AM
sir could please send the code for I2C and wifi interfacing with 8051
Tue May 19 2020, 10:29 PM
Does anyone have microcontroller programming software for STC15F104W (core 8051, 4 k, 128 byte, 6 I/O pin, UART ... DIL8), that works?
Sat May 02 2020, 07:38 PM
Tamu Gurung
Hi I am looking for a assembly language program for a digital decimal counter. Time counts max limit of 2 mins starting from 2.00 mins and ending at 0.00. time is to be displayed on 4 7-segment LED displays. Edsim51 simulator to be used. Thanks
Wed Mar 25 2020, 01:39 PM
Sir kindly send the code file i2c for 8051
Fri Mar 13 2020, 10:36 PM
@ Rohitnani,ABEBE..which project ?
Fri Mar 13 2020, 12:55 PM
how can get hadwere of this project
Sat Mar 07 2020, 05:11 PM
Sir, Could you please send me the zip file input password....
Wed Feb 26 2020, 04:58 PM
Peter Parker
Is it possible to send multiple messages using only 1 GSM module?
Sat Feb 01 2020, 10:12 AM
Pearl Olin
Wed Jan 22 2020, 06:16 PM
I m getting errors while simulation process during interfacing socket output and lcd... Can i get the report of ur project which is same as us.



Thu Jun 25 2020, 03:46 PM
Mon Jun 22 2020, 03:03 PM
Tue Jun 16 2020, 05:10 PM
Sat Jun 13 2020, 09:43 PM
Thu May 21 2020, 12:44 PM
Thu May 21 2020, 01:28 AM
Wed May 20 2020, 07:05 PM
Wed May 20 2020, 11:52 AM


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Forum Activity
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Jul 01 2020, 11:07 PM
PS: I am a new learner thats why my question may s...
Mirza123 Avatar
Posted By Mirza123
Wed Jul 01 2020, 02:05 PM
Thanks for the assistance. I have read the data sh...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Jul 01 2020, 10:12 AM
See section 15 (Ports) of the data sheet. ...
wimac Avatar
Posted By wimac
Tue Jun 30 2020, 10:05 AM
How did you know that it is not 8051. Mirza123It i...
Mirza123 Avatar
Posted By Mirza123
Tue Jun 30 2020, 08:39 AM
It seems ports on the AT89LP2052 is not like on th...
ExperimenterUK Avatar
Posted By ExperimenterUK
Tue Jun 30 2020, 08:34 AM
It seems ports on the AT89LP2052 are not like on t...
Mirza123 Avatar
Posted By Mirza123
Thu Jun 25 2020, 04:07 PM
Hello!i am trying to use AT89LP2052 ( AT89LP2052 h...
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Posted By ExperimenterUK
Wed Jun 17 2020, 09:42 PM
It is about capacitor? i should put it between Vcc...
cerouno Avatar
Posted By cerouno
Wed Jun 17 2020, 10:37 AM
Take another look at the power supply to the LCD.A...
ExperimenterUK Avatar
Posted By ExperimenterUK
Wed Jun 17 2020, 02:01 AM
Take another look at the power supply to the LCD.A...