Monday, January 18, 2010

Science Project - Fishing Pole Vibration

We've learned in the past that it is best to start science projects early... plus its been rainy out and we need something to do!

This year one of the projects is to measure the stiffness of different fishing poles - we had to tie fishing into it.

Here you can see a small accelerometer soldered to a small PCB - we've used these in the past to record vibration and shock using a microcontroller. Today we used the Labjack to capture the accel data.

You can see the vibrations of the fishing pole here on this software.

The IC is an old ADXL105 accelerometer - good for up to +/- 5G's.

Our plan was to measure the vibration of each fishing pole at the tip and middle of the pole as we pulled the tip down and released it. A simple 'pluck' test to watch how fast the pole stops vibrating.

We compared 3 different rods - a GLoomis backbounce (salmon) rod, a AbuGarcia Medium action (steelhead) rod, and a very light fly rod.

Here is one of the rods clamped down to the table - to act like a fixed cantilever beam.

Our software is able to sample 2 channels at 600 samples per second. There is a danger of anti-aliasing because we aren't filtering out the higher frequencies... but since this is for a 5th grade class, we will just talk about sources of error...

Here is the accelerometer clipped to the end. The board and sensor are fairly light, and are held on by a simple paper clip.

Both will add weight and skew the data - as will the wires, but again, we're after fun and not accuracy!

Here is the other accelerometer at the middle of the rod.

To run the test, we pulled down the tip of the rod one foot from its 'equilibrium' position, and let it go.

This guy isn't convinced. He wants to see confidence levels and error bars on ALL the data!

That's called "peer reviewing"!

We collected some data and had fun. We'll collect more, and compare the 'action' of the different rods.

Hey - it quit raining outside... lets go fishing!