So I have decided to try and use my electronics knowledge to the max and build a bomb defuse game.
The first part of this is I need a timer that will countdown from 3:00 to 0:00. I already have a 555 timer and have looked on the internet for a countdown timer but have not found a schematic. So if anyone here has a schematic of a countdown timer, can I use it?

Thanks

 

So what have you done to solve this problem?

 

Just a few:

http://nodasystech.com/design/digital-countdown-timer-schematic-diagram.php
http://www.turbokeu.com/myprojects/countdown3.htm
http://www.electro-tech-online.com/attachments/3decadeupdowncntr1-gif.66638/

 

So what have you done to solve this problem?

I came here because I have not solved the problem... and needed a schematic for a 3:00 countdown timer.

 

I give you some of the requirements:
-No Arduinos (sorry)
-Auto reset after finish
-And obviously a start button.

 

-.- I have spent Hours looking for a countdown, so instead I may just buy a kit. But thanks for the replies *big sigh*

 

Cheaper and much easier to buy a ready made one.... Ebay

http://m.ebay.co.uk/itm/12241140661...f415b0aa64b11df704fffede59|iid:28&_mwBanner=1

 

Sorry about the duplicate post, I thought it might be too similar but I still gave it a shot.
Woops, Bod

 

I have spent Hours looking for a countdown, so instead I may just buy a kit. But thanks for the replies *big sigh*

Not many would design a circuit to do what you want. Minimally, it would take 3 counters, 3 BCD to 7 segment display decoders, 3 seven segment displays, a couple dozen resistors, some misc decode logic, a 555 timer, a switch or three, and a handful of capacitors.

If you really want to do it as a learning exercise, members can help you design it.

 

Use Dodgydave's suggestion. What do you want to happen at the end of the countdown? I've opened ones similar to these and added external inputs and outputs.

Ken

 

I have found a kit that I will go with because it is more convenient and also it would be smaller than me making it myself.
But thanks for the replies anyway!