Pcb countdown timer

timer004 timer003 timer002

This is a countdown counter based on ATtiny2313, primary developed for my PCB exposure box, but it can be used for other purposes too.

The counting range is between 1 and 90 minutes and it can be adjusted with up or down buttons (high and low in the pictures).

After the desired time is set, the countdown starts by pressing the start/stop button (on/off in the pictures). By pressing the same button we can interrupt the counting at any time we want.

After the count expires we hear a beeping sound and the load is disconnected. By pressing start/stop button we reset the counter and we are ready for another lap. All actions included the time remaining are shown in the LCD display.

The schematic is shown here:

PCB timer sch

And the PCB:

PCB timer brd


PCB timer silk


PCB timer silk1

Click on the images to get larger view.

The timer was originally build using the AT90S2313 but is obsolete now. Anyway the ATtiny2313 and AT90S2313 are pin to pin compatible and you can use it if you have it.

The code for the micro was developed using BASCOM-AVR. Download the source code and the hex file from here:

Source code: Download timer16LCD.bas

HEX file: Download timer16lcd.hex

The schematic and pcb was made with Cadsoft’s eagle. Download the .sch and .brd files from here:

.sch file: Download countdown timer.sch

.brd file: Download countdown timer.brd

You can program the ATtiny2313 on board by using the 6-pin header which is compatible with the 6-pin header of STK-500. If you use STK-500 to program the micro you have to remove the VTARGET jumper first or the STK-500 will be damaged. The ATtiny2313 is shipped with internal oscillator selected by default, so you have to program the appropriate fuses by yourself. Use the on-line AVR Fuse Calculator and set the settings for the fuses (see the photo, click to get a larger view).


A bug found in the placement of transistors T1, T2, T3 in PCB.
The correct is the reverse of the drawing in silkscreen. The schematic it’s ok.

if you have any questions submit a comment or send e-mail: dselecdim at gmail dot com

  1. suhai
    24/10/2010 at 3:27 pm | #1

    can you email to me the original picture of kompenan pcb time control.

  2. Brian
    22/12/2011 at 11:33 pm | #2

    Hi there

    Is it possible to the the PCB layout in a PDF file ? Then it will be possible to print it out in scale 1:1 – to make sure, that things align correctly


  3. 20/07/2012 at 10:25 pm | #3

    unable to download the file

  4. 25/08/2012 at 4:09 am | #4

    Hello there! I just wish to give you a big thumbs up for your great information you’ve got here on this post. I’ll be returning to your site for more soon.
    BR Removal Services
    27a Jade Close Unit 2
    E16 3TY
    United Kingdom
    0800 001 6111

  5. 21/10/2012 at 9:53 am | #5

    sir can i have the 1:1 scale of the circuit design? just email it to me.. tnx..

  6. 13/02/2013 at 10:14 pm | #6

    Hello! Do you know if they make any plugins to safeguard against hackers?
    I’m kinda paranoid about losing everything I’ve worked
    hard on. Any recommendations?

  7. 15/02/2013 at 4:23 am | #7

    You’re so cool! I do not suppose I have read through anything like that before. So great to find another person with a few genuine thoughts on this topic. Seriously.. thanks for starting this up. This site is one thing that is required on the web, someone with some originality!

  8. 04/04/2013 at 7:32 pm | #8

    Thanks for a marvelous posting! I seriously
    enjoyed reading it, you can be a great author.
    I will always bookmark your blog and will eventually come back at some point.

    I want to encourage you continue your great work, have a nice

  9. 08/04/2013 at 7:04 am | #9

    It’s perfect time to make a few plans for the long run and it’s time
    to be happy. I’ve read this put up and if I may I want to recommend you some fascinating things or suggestions. Perhaps you can write next articles referring to this article. I want to read more issues approximately it!

  10. 10/04/2013 at 6:53 am | #10

    There is certainly a lot to find out about this topic.

    I really like all of the points you made.

  11. 11/04/2013 at 7:01 am | #11

    Hi, after reading this awesome piece of writing i am too glad to share my experience here with mates.

  12. 25/06/2013 at 3:11 am | #12

    Hi there, this weekend is good in support of me,
    because this occasion i am reading this great informative paragraph here at my residence.

  13. 11/09/2013 at 1:01 am | #13

    Thanks for every other informative web site. Where else may just
    I get that kind of info written in such a perfect way?
    I have a challenge that I am simply now operating on, and I have been at the glance
    out for such information.

  14. 02/03/2014 at 10:40 pm | #14

    Hello! I could have sworn I’ve been to this website before
    but after reading through some of the popst I realized it’s
    new to me. Anyhow, I’m definitely gkad I found iit and I’ll bbe bookmarking and checking back often!

  15. 28/03/2014 at 4:43 am | #15

    gillette aveeno professional samples

  1. 10/09/2011 at 9:58 pm | #1
  2. 18/10/2011 at 12:22 pm | #2
  3. 25/08/2013 at 6:56 am | #3

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

%d bloggers like this: