This timer uses a rolling ball to count seconds
This timer uses a rolling ball to count seconds
Arduino Team — July 12, 2023
Before there were sophisticated digital clocks – or even spring-powered mechanical clocks – most methods of measuring short periods of time relied on gravity moving something in a consistent, repeatable way. Water clocks and hourglasses work on this principle. But it's not much fun watching grains of sand fall, so Brett Oliver built a kitchen timer that uses a rollerball to count the seconds.
This project started with a rolling ball escapement designed by JBV Creative. This mechanism simply rocks back and forth as a ball bearing rolls from side to side of the track. Perpetual motion is impossible, of course, so this mechanism relies on weight to turn the gear system that rotates the caterpillar. The ball is only there for timing: when it reaches the end of the track, it pushes a lever which releases the mechanism and lets the weight drop a little. This will work until the weight hits the ground or there is no more cord.
Oliver turned this mechanism into a kitchen timer by replacing the weight with a stepper motor controlled by an Arduino Nano board. Because the motor ultimately drives the mechanism, it can continue to operate as long as it is energized. An LCD display shows the remaining time and the user can adjust it with a few buttons. An MP3 module plays a user-configured sound effect when it reaches zero. The speed of the stepper motor determines how long it takes the ball to cross the track and the default is five seconds, so the timer increases by five seconds with each pass.
It may not be more convenient than a standard kitchen timer, but it's much more interesting to look at.
Arduino Team — July 12, 2023
Before there were sophisticated digital clocks – or even spring-powered mechanical clocks – most methods of measuring short periods of time relied on gravity moving something in a consistent, repeatable way. Water clocks and hourglasses work on this principle. But it's not much fun watching grains of sand fall, so Brett Oliver built a kitchen timer that uses a rollerball to count the seconds.
This project started with a rolling ball escapement designed by JBV Creative. This mechanism simply rocks back and forth as a ball bearing rolls from side to side of the track. Perpetual motion is impossible, of course, so this mechanism relies on weight to turn the gear system that rotates the caterpillar. The ball is only there for timing: when it reaches the end of the track, it pushes a lever which releases the mechanism and lets the weight drop a little. This will work until the weight hits the ground or there is no more cord.
Oliver turned this mechanism into a kitchen timer by replacing the weight with a stepper motor controlled by an Arduino Nano board. Because the motor ultimately drives the mechanism, it can continue to operate as long as it is energized. An LCD display shows the remaining time and the user can adjust it with a few buttons. An MP3 module plays a user-configured sound effect when it reaches zero. The speed of the stepper motor determines how long it takes the ball to cross the track and the default is five seconds, so the timer increases by five seconds with each pass.
It may not be more convenient than a standard kitchen timer, but it's much more interesting to look at.
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