An enclosure for a battery-powered device that can be attached to a water reservoir (e.g. a bucket). Attach a float switch, a lithium ion battery, a USB charging circuit and e.g. an ESP8266 microprocessor with Wifi to build a small device that notifies you when the water reservoir runs low. You will need a few things to assemble the water level sensor: These parts cost about $1 each. These parts cost about 10$ each. See my github repository for code and further information. Attention: Be careful with Lithium batteries. I have not tested this enclosure for safety. It is certainly not entirely weather-proof. Safety will depend on your choice of batteries, battery protection circuits, charging circuits etc. I do not take any responsibility if you're batteries suddenly catch fire. If you want to make changes to the model, download originals.zip which contains the JSCAD source files.