Beeping Down Counter

           One of the most basic circuits in all of digital electronics is the up/down counter with a 7-segment LED display. While you could easily build a similar circuit using all software and a microcontroller, understanding how to build the same circuit functionality entirely in hardware will give you an edge as a design engineer.
           Since there is still a little bit of time to submit another entry to the 7400 competition over at dangerous prototypes, I thought it would be interesting to give some insight on how to build the circuit from a signature movie prop in the film Iron Man 2 - a beeping down counter.

Beeping Down Counter - Video Overview

Beeping Down Counter - Setup

My 'Movie Prop'            vs.            Iron Man 2

(My Version Uses Play-Dough!)
Purpose & Overview of this project
           The goal of this project is to duplicate the down counting circuit used by the character Ivan Vanko in Iron Man 2 to aid his escape from prison in Manaco. There are three key components that go into this design:

• A Down Counter With Dual 7 Segment LEDs
• A Push Button To Initiate The Down Counting
• A Quick 'Beep' Sound With Each Down Count

These goals will be accomplished by using a combination of 555 timers, 7400 series and 4500 series logic devices. The 555 timers will be used to drive the 'beep' sound and the main down counting. The 7400 devices will be used to control state outputs for the system and the 4500 devices will be used to set the current count value on the 7 segment LEDs. No software will be used in this project.
           There are two unique challenges present in building this device. The first is that I have no idea what the authentic device would look like-only what I saw in Iron Man 2, so I'm building a unique design for how I would make the movie prop circuit with logic devices. The second is that I want the entire project to fit on a single breadboard, which limits how much functionality I can pack into the project.