A microprocessor-controlled window fan

The fan assembly was bought in the 1990's because of a favorable quantity purchase of surplus 120 mm server fans. Where I live it cools off quickly after sundown due to the wind off the pacific ocean. I do not need central air conditioning, so bringing outside air cools off the bedroom before going to bed and saves money. This assembly has served well every summer since. The assembly is made to fit vertically in the window and is easilyinserted and removed.
Originally the fans were controlled by a box with a rotary switch which selected fans in banks and in series or parallel.
In 2007 the present box was substitued which contained an 8-bit picaxe. This was in use until 2016, when the thermister temperature sensors were replaced by LM335 band-gap integrated circuits, necessiting an 18-pin picaxe. The fan assembly is original except for the outside temperature sensor. The control box is unchanged from the 2007 version except for the processor and LED assemblies.