Gag Bomb Countdown Timer

Building the Electronics Building the electronics is the toughest part of the project. I have used 8051 microcontroller for this part of the project, mostly because it’s really cheap and programming the microcontroller is really easy.

• 8051 microcontroller:

I have used a prebuilt 8051 module that I have bought online. It’s really simple to build it yourself over a PCB if you have little knowledge of electronics. The schematics are widely available over the internet. Please find below the circuit for same.

• 7 segment display:

“7 segment display” is the most basic display in electronics that will display digits from 0-9. I have connected 4 seven segment display in series to display minutes and seconds.

• Switch array:

I have connected four push switches in array. The switches would be used to set or reset time.

• Piezo buzzer

A buzzer to beep when the alarm goes off or when countdown timer comes to a halt.

All you have to do now is to connect all of these components together, 8051 microcontroller, 7 segment display, switch array and piezo buzzer. I have used a lot of colorful jumper wires to connect the components together.

Programming the microcontroller: I have used embedded C for programming the microcontroller. Calculating the oscillator cycles to get the exact interrupt every second was tricky. The code is available in the below github path

https://github.com/chandrakanth527/countdowntimercode_8051

Building the Gag Bomb Base: Building the Gag Bomb base is the fun part of the project. All the materials for this part of the project would be available at home.

I have rolled newspapers to make the cylindrical core for the dynamo. I have wrapped the rolled newspaper with brown book cover, if brown book cover is not available you can use paper bags. I have used electrical tape to join all the rolls together. Using double sided tape I have fixed the electronics to the gag bomb base.