What is this electronic set up with a red light on top of it?
Based on the concrete slabs with access doors and vent pipes around it, that's almost certainly a waste water lift station control and monitoring unit.

Lift stations are used when waste water drainage and/or local sewer lines collect at a point below the existing main sewers. They pump the water back up into the sewer system where it can be gravity fed to the water treatment facility. They are very common in fairly flat areas with a high water table (like South Florida, where the OP's pic was taken).

The red light on top can be used to indicate an active pump or alert to a failure. If the light is on for more than a few minutes, you should definitely call the numbers on the posted signs. 



Brief article: "What Are Lift Stations"

Brief video: "How a Lift Station Works"

Image Source and a diagram of inner workings.