A friend has a Masters costume and wanted me to make him a TCE (Tissue Compression Eliminator). He showed me photos and some videos of the actual prop and it seemed like a simple prop until I really got into it. It took 3 tries before I got something that sort of worked.
I put in 2 LEDs (White and Red) and there are 2 switches on the side that control them.
I did document how I made the TCE here.
Dr Who - Tissue Compression Eliminator
Someone has a video on youtube of the TCE he made and some sketches of his internal workings. I didn't try his method as I thought my first method would work straight away.
My TCE is not bad durability wise but I sure would not whack it or hit something with it.