Our measuring instrument is a guillotine like device that we can use to break chips. For now we practiced with dry spaghetti as they are less messy and easily accessible. The two sensors we use are a load cell at the tooth of our guillotine to measure the force and a potentiometer to measure the displacement change as we move down. We filter the signal from the load cell using a self-made instrumentational amplifier and measure the voltages with an oscilloscope.
The photo of the oscilloscope output below shows a typical measurement outcome when breaking the spaghetti. The blue channel is proportional to the displacement while the yellow channel represents the force on the spaghetti. The individual peaks in the force are single spaghetti breaking and the force dropping momentarily.
Whilst the photo of the screen might suggest a very clear output, when downloading the data to the computer and looking at it in higher resolution the displacement channel seems to be very noisy. We can filter out this noise electronically and we can do it quite radical as we expect no fast variations in the displacement. The top two diagrams below represent the displacement and force channels before computational filtering. The bottom diagrams represent the same quantities after we have run our code.
We can easily do this to all our measurements and produce force-displacement diagrams from them. I will keep you updated as we make progress. Our kitchen will soon be ready