Well, the components have arrived. Quite nostalgic, placing an order with Rapid Electronics after all these years. Back then, the orders would have mostly been components for GCSE pupils studying Design & Technology, the option involving electronics and computer control.

The first step was to build the circuits on a solderless breadboard to make sure they work. This resulted in my re-learning something about infra-red beams and detectors that I learnt a long time ago – I could only get the sensor to detect the IR emitter from a distance of about 5 cm. Bit of a problem getting a bat to fly through that. It’s getting quite annoying, the way that when I learn something nowadays, I have enough memory left to remember that I knew that already – once.

Now of course, IR beams can be easily detected over distances greater than 5 cm. – I can sit in my armchair and turn on the TV with a remote from a somewhat greater distance than that. Problem is – I don’t know how it’s done.

Lateral thinking – I bought a laser level last year. Shines a beam which gives a red line along the wall from the level which was equipped with the traditional bubble in a tube of liquid. Didn’t need it, but couldn’t resist owning a laser and maybe finding a use for it.

So … how about a laser beam instead of an IR beam for the bats to fly through?

To be continued …