Home >> Science & Nature >> Science

How to Create an Accelerometer

Miniature accelerometers are in devices like cellphones and computers. You can̵7;t build a miniature version without very expensive fabrication equipment, but you can build your own accelerometer. Your accelerometer, like all others, will depend on measuring consequences of Newton̵7;s second law of motion, that force is equal to mass times acceleration. You̵7;ll set up a situation where you can measure a change in position that corresponds to the force, which in turn corresponds to acceleration.

Things You'll Need

Metal weight
Two identical springs
Box to fit weight and springs
Toothpick
Glue

Instructions

- 1
  Attach one spring to one side of the weight and the other spring to the opposite side.
- 2
  Attach the two springs to opposite ends of the box. The box can be an open frame, a cigar box, a cookie tin ̵2; ideally a rectangular box large enough to contain the weight and springs, but not so long that you need to work hard to attach the springs, and not much wider than the weight and spring.
- 3
  Glue a toothpick to the weight so it sticks out at right angles to the springs, pointed to one side of the box. Glue or tape a piece of paper to the side of the box where the toothpick points.
- 4
  
  As long as a spring isn't stretched too much, the displacement is linear with acceleration.
  
  Turn the box upright, so that the springs are vertical, one above, and one below the weight. Mark the spot where the toothpick points. That displacement is in response to 1 g of acceleration, which is the acceleration due to the Earth's gravity at the surface of the Earth.
- 5
  Flip the box over so that the top spring is on the bottom and the bottom spring is on the top. Mark the spot where the toothpick points.
- 6
  Mark the spot right between the two toothpick points. You know have a scale for your accelerometer, with marks for plus and minus one-g acceleration, and for zero acceleration. The scale is linear, so an acceleration of one-half-g will have the toothpick pointing halfway between your middle mark and one of the end points.

Science