Monthly Archives: January 2016

IOT enabled toilet flush tank

This is not a trivial use case as far as my house is concerned. Now and then our toilets malfunction and keep leaking water into the bowl after a flush. The flush tank never fills up as the water keeps flowing into the bowl. Others in my community have also reported the same issue. Since water is a scarce resource in my community as in most parts of Bangalore, I rigged up one of our toilet’s flush tanks with a WiSense water level sensor which sends the  tank water level to the WiSight application in the cloud (AWS). WiSight then sends an SMS if the water level remains low for more than 2 minutes after the tank  is flushed.

The prototype has been working well for two days now. For now, the water level is sent to the cloud every 10 seconds. This frequency can be cut down by reporting water level data only when water  level changes by say +/- 10 %. The frequency can be increased when the toilet is flushed and until the water level does not come back to normal (full tank).

The sensor node comprises a WiSense WSN1101L (operating in reduced functionality mode) and a Freescale/NXP pressure sensor. The node is  powered by two AAA batteries. The node is sending data every 10 seconds to a  WiSense coordinator node  (WSN1101C) connected to a Raspberry PI. The PI is forwarding the data to WiSight hosted on AWS.   Note that WiSense nodes operate in the 865-867 MHz license free band in India.

Here are some pics of the prototype.





Below are two snapshots of water level data from WiSight.