Dishwashers have become so pervasive in households that most people would not survive the day without running them. We all know the spiel: dirty dishes go in, we hear water slushing and spraying, then ta-dah! clean dishes come out. The data science team at Sense decided to dig a little deeper into what’s really happening in a dishwasher. Here are some under-the-hood features you did not know about your dishwasher.
Basic dishwasher design
The basic design of a dishwasher has not changed that much since first invented by Josephine Cochrane in 1886. Nowadays, most dishwashers consist of two main building blocks:
A segment of a typical time signature for a dishwasher run is illustrated below.
Consistent motor-heat timing
There is a very distinct time relationship between the dishwasher pump motor and the heating element. This time correlation could be different from one dishwasher brand to another, but it is pretty consistent across multiple runs of the same brand. This time relationship is illustrated in the figure below.
Brand-specific motor sequence
Some dishwasher brands have such a specific circulation pump motor sequence, that one would be able to distinguish a brand from another from this time signature alone. The figure below illustrates part of the motor signature for a particular dishwasher brand.
This sample of dishwasher features illustrates the many challenges we face when modeling and automatically detecting an appliance. Questions our team asks are: how is a motor different from a heat element? what makes a motor part of an appliance? how do we model the relationship between various parts of a device? Each of these questions brings with it a set of interesting problems and discoveries.
The variable features demonstrated above are also typical of the interesting patterns we see when investigating different appliances. Such variability introduces complexities in our disaggregation models, but also provides interesting cues that can be exploited to achieve high accuracy.