Discussion in "Project Help" started by    13kelly    Jul 22, 2008.
Sat Aug 09 2008, 05:02 AM
here is a sample ciruit on how to interface a relay with oe port pin of the uC. Similar ckt can be used for the Horn/strobe .

strange: no attachment button :-s in reply?

[ Edited Sat Aug 09 2008, 05:03 AM ]
Sat Aug 09 2008, 02:34 PM
sorry pid33, it was just for security, you can now upload files.
Sat Aug 09 2008, 04:38 PM
thanks ajay,
here is the circuit.

 13kelly like this.
Sun Aug 10 2008, 06:15 PM
Thanks for the cct, and the help. :-)
I have been resting over the weekend here.
I will try to up load a revised diagram for criticism asap with a flow chart for operation.

Tags cctasap
Wed Aug 13 2008, 11:05 AM
pdi33 and Arun,
I am trying to get a final diagram together for this weekend so I can concentrate on my final exam.
I was looking at your Queing Display System Diagram project and was hoping if you could help me to use two Seven segment displays to display up to 60 minutes when €60 is validated and then decrement the timer when a start button is pressed.
There should be a second set of Seven Segment display to operate seperately to the first display when a room B button is pressed but do the same task, increment display during validation and start decrement by a seperate start button.
Does this need a seperate clock to run the second display unit?


This would make my project easier in that there would be no need for an LCD unit.
Wed Aug 13 2008, 02:12 PM

Hi Kelly,

Yes, you can have 2 set of timers running of the same clock,in that case there'll be total of 4 nos.of 7seg-displays ( two each for one countdown timer).

pl.go thru the following thread where i have discussed how to drive 10 devices using only one timer( each device operates at different duration) :


Thu Aug 14 2008, 11:28 AM
Here is a draft of the project so far.
Am I ok with the positioning of the 7 segment units?
How would I choose between activating display 1 and display 2 prior to validating notes.do I start the countdown for display 1 and for display 2 seperately?
Could you help me with code to set up 1 minute routine, 5 min routine, 20 min routine and 50 min routine.?


Thank you
Thu Aug 14 2008, 03:37 PM

Hi Kelly,

Here is a draft of the project so far.
Am I ok with the positioning of the 7 segment units?

i can't see it ............
Thu Aug 14 2008, 04:07 PM
Have attached the diagram as a word doc.
Hope you get it this time.

Thu Aug 14 2008, 07:56 PM
hi kelly,
i think u missed out on the instruction below the reply window.
it instructs as below:

Please note
Allowed file types: | .zip | .gz | .jpg | .png | .gif | .rar | .pdf |
Any other file types uploaded will be instantly deleted.
Maximum file size: 2M "

please convert ur format from doc to any of the above mentioned formats and post it on this thread.Please do not create multiple threads.
I am deleting the duplicate thread "draft2" u had created as it too did not contain the required document u seem to have attached (again i think in .doc format).

U can always download 'winzip' which is shareware and use it to compress the file to zip format before attaching it.

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Sat Oct 12 2019, 10:23 PM
Log in.. then post your code in the 8051 forum
Sat Oct 12 2019, 10:18 AM
Bhadra Sajikumar
i am doing a countdown timer with 8051 for my project, unfortunately our professor had to take a leave of absence before he could teach us most of it.. can someone explain the .asm code of it for me?
Mon Sep 23 2019, 07:37 AM
I am doing a project for my schools wireless security system with cameras,sensors and spot lights using 8051 micro controller, could you help me out with the design and its source code.
Wed Sep 18 2019, 08:48 PM
Caryn Kover
Thank you for your time,
Mon Aug 05 2019, 07:09 PM
@Ismail ..post in forum, give details
Mon Aug 05 2019, 04:33 PM
Ismail balghmi
Hello. Please I won't download
Wed Jul 24 2019, 12:47 AM
@BUSTER123 Please post in the forum
Tue Jul 23 2019, 06:13 PM
hello! newbie here. i am kind of a guy who hates using ready - made existing libraries, so this helped a lot as i was trying to control and write to a character lcd display. however, i can't figure out how to set the cursor position. for example, i want to set it to the 5th column in the first row, so position 5. so according to the table, i am sending 10000101 on the 8 data lines of the lcd (register select pulled low). the cursor does not move there however. and i cant move the cursor left or right too. is it something wrong that i am doing? thank you.
Thu Jul 11 2019, 07:55 PM
@ramos https://www.theengineeringprojects.com/2017/09/l298-motor-driver-library-proteus.html
Thu Jul 11 2019, 07:44 PM
@praveen123. Can you give a link to the project ?



Wed Nov 13 2019, 06:25 AM
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