Comparative measurement using particles within one or more compartments

A system comprising:

• a first compartment containing one or more first particles, wherein the one or more first particles are configured to move in response to an external stimulus;
• a second compartment containing one or more second particles;
• and
• a measurement circuit configured to generate a measurement based on comparing a first measurement associated with position of the one or more first particles and a second measurement associated with position of the one or more second particles.