I have three sensors, an MPU6050 (6 DoF sensor), FSR400 (force sensor) and an audio sensor. I am interested in finding the points of interest within these signals and be able to say a certain action is taking place in the POI. 

I am very new to DSP and I am trying to write a code in python where the signals would be represented as coloured pixels. But before this happens, I would like to be able to come up with a way to simply look at a plot of a signal and point out where my actual data is and what happens at a particular point. So far, I was able to do that in terms of my wiring where I included a pair of wires which would act as a kind of a switch or reference point which could be touched to produce a voltage. And this plot can be superimposed onto the force sensor plot to show "reference points". 

Is there a way or strategy to be able to do the same thing without the need for any hardware or coding to hypothesize the presence of a reference point by considering the properties of a signal? 

Force sensor plot with reference points superimposed.