and7barton

I once installed a tannoy on my car, and once or twice, parked up in a local street and played, from my cassette player, the sound of my son's musical box. The kids used to come out of their houses, clutching their pennies to buy an ice cream. Of course, there would be no ice cream van to be seen.

And it worked. Every thing I ever built never worked. I even once built an amplifier that made the signal quieter. Now, that take some doing.

Would it be feasible to have real fireflies ?

I make my own dry ice by squirting my big CO2 extinguisher into a canvas bag for a minute.

I'm looking forward to the digital version of this ! :-)

A good project, except that here in the UK, the police would soon be knocking at your door and demanding you remove it. Only official speed detectors are permitted here.

I've read articles to the effect in the newspapers. Often people have stuck a camera up, or a dummy camera. It invariably results in the police requesting that it's removed. The usual excuse is that it could be "a distraction to drivers".

I mould the sand / clay mix around the outside of a polystyrene (Styrofoam) cup, then allow to dry for a few days. When set, just run your propane torch around the inside to burn off the polystyrene. You get a nice smooth inner surface.

Actually it's YOU who seems clueless. You anneal copper by heating to a dull reddish black and QUENCH in cold water. The same process is used for brass and aluminium. To anneal steel, you heat and cool down as slowly as possible. With steel quenching hardens it. So annealing copper uses the exact opposite process that you'd use for annealing steel.