Hardware - The Big Beepin' Egg Timer
This project was motivated by a problem I heard about from a friend. At the Burger King where he works, employees should take no longer than three minutes to build a burger; however, at his Burger King, no way to measure your burger-building time was supplied.
Initially, I suggested buying a watch or an egg-timer from the local dollar-store, but I was soon reminded of why that was not a great solution: it was too easy and rather boring.
And so began the design and construction of the Big Beepin' Egg Timer.
The timer had to do one very simple thing: it had to count down from 3.00 minutes to 0.00 minutes and then beep. Consequently, I designed it to be very easy to operate. It had just one button - a very large, red one - that the user would press to turn on the device and start counting down from 3 minutes. Pressing the button while the count was already in progress would simply reset the count to 3 minutes. When 3 minutes elapsed, the device beeps for 1 second, and then switches to a low-power mode.
I used a 32.768 kHz crystal and a PIC16F84A microcontroller as the heart of the device, taking advantage of the PIC's low-power "sleep" mode so that one-button operation would be possible. There is no need for an "off" switch, because once it's done timing, it just goes to "sleep", where it consumes very little energy until it is awakened by someone pressing its big red start button.
| The picture to the right shows the insides of the timer. It was rather difficult to fit everything into a case of a reasonable size. |
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I bought nearly everything for this project from www.futurlec.com , which is, in my opinion, a great place for a student like me to purchase electronics components cheaply.