세상에서 가장 시끄러운 알람시계

 Alan Parekh 가 세상에서 가장 시끄러운 알람시계를 만들었다...
화재경보기와 알람시계의 결합으로 아침을 깨운다고 한다. 무서운 사람이다... ㅋㅋ

원문 전체는 http://www.hackgadget.com 에 있다.

Overview

알람소리가 적을 때가 있는가? 이 디자인의 알람시계라면, 절대 그럴 필요가 없다. 이 hack 는 싼 값으로 만들수 있고, 기존의 화재 경보 벨을 이용해 만들었다. 알람신호는 시계에서 빼와서 간단한 회로를 이용해서, 만들었다.

From http://hackedgadgets.com/2008/01/11/fire-alarm-bell-alarm-clock-worlds-loudest-alarm-clock/8/
by Alan Parekh 

 

Parts needed and Interface Board Schematic

회로에 필요한 부품들

Cheap Alarm Clock
Fire Alarm Bell
PNP Transistor
4.7K ohm resistor
360 ohm resistor (optional)
Blue LED (optional)
Perf Board

Take apart the Clock, see how it works

시계분해하는것은 드라이버로 간단하게 분해가 가능하다. 몇번의 드라이버 질이면 끝.

 

Take apart the Bell

벨부분은 그다지 할건 없다.

 

Mod the Clock to have an Alarm Output

The mod didn’t go very well. The plan was to scrape away the solder mask from the trace going from the bottom alarm switch pad and solder a small wire to hijack the negative signal when in alarm. In the below picture you can see the bare copper after the solder mask was removed. Read below to see what happened when I attempted to do this.

For strain relief some hot glue was used to keep the wire from moving. Have a look at the left of the clock assemble, that is one of the adjustment knobs and the black thing is the plastic guide that normally keeps it in place. Everything is so small and delicate… Some crazy glue solved the minor setback.

This is the test circuit in a breadboard for testing.

Initially the plan was to solder the wire to the positive battery connection and the trace that was exposed earlier. That worked fine for about 5 minutes but before I could employ some hot glue strain relief the tiny trace pulled off the board. The only option was to solder the wire to the copper under the alarm contact. Problem with that is that this would physically interfere with the mechanical alarm On/Off switch. The solution was to rip out the On/Off alarm switch.

 

Build and install the Interface Board

After testing on the breadboard and confirming proper operation the next step is to solder it to a more permanent perf-board. The board needs to be cut to fit into the bell opening.

Some coat hanger wire was used as a stand. There are dozens of better solutions however nothing else was at hand…

 

Put it all back together

A small nail was used to mount the clock to the back of the bell. All of the wires fit into the cavity between the board and enclosed bell motor.

 

Completed Project

All done, all you need to do is plug it in and set the time and alarm time.