What does the software do
In essence, the Arduino sketch records the voltage measurements and transfers them to your computer/device. The Processing code uses an algorithm (called Fast Fourier Transform or FFT) to sample the signal over a period of time (several minutes) and divides it into discrete frequency components.

If you want a detailed technical explanation of FFT see wiki/Fast_Fourier_transform.

 

Why is the software useful

It can be hard to understand what is happening in real experiments by just looking at the (raw) voltage measurements so a little help is very useful. This is due to several factors including spikes, electrical noise, drift, etc as illustrated in example below (recorded with PICO ADC-24):

 

Initially the voltage between the electrodes is very small (just background noise) but after the tube grows and makes a connection there is an initial spike. The slime then oscillates at approximately 0.015 mHz for about 500 seconds. This is followed by more spikes and then oscillations of approximately 0.017 mHz for about 400 seconds. Therefore, the speed of the slime’s oscillations has increased (probably due the tasty oat flake it has just found to eat).
The software makes analysis easier by filtering out unwanted noise/spikes and automatically calculating the fundamental frequency of oscillation when the slime is ‘stable’.
Why are the software settings adjustable
If everyone wanted to do the same experiment we could fix the settings on suitable values. However, those settings wouldn’t be optimal for other experiments. As we don’t know what experiments users would like to try we’ve configured the software so users can adjust settings.
Obviously, some setting aren’t ideal. For example, if you collect 860 samples per second (SPS) for 2 weeks you’ll have a massive data file. Conversely, if you only sample once per hour you’ll have ‘missed all the action’. A reasonable compromise would be 64 samples per second.
What software settings can the user change
We’ve had to strike a balance between ‘easy of use’ and ‘functionality’. We don’t want to restrict what users can change but the benefits of changing some settings are minimal. We’ve therefore only included some setting in the Graphical User Interface (GUI)
Users who want to adjust settings which are available via GUI are welcome to edit the (open source) code. If you find benefits please let us and we’ll consider adding extra settings on GUI.
Setting Min Typical Max
Samples per second (SPS)
8 128 860
Duration (minutes)
1 7200 Slime’s life and computer data storage capacity
Number of BINS
128 16384 262144

 

How to change software settings via GUI

Step by step guide to recording and analyzing measurements.