illuminated ball - remote switching and charging

I'm working on making an illuminated ball for playing bike polo with at night time. A couple of high output red LEDs are sufficient for light to get through a normal street-hockey ball. The problems I'm currently facing are switching the lights on or off, and charging the batteries. Ideally both of these could be done remotely - i.e. without having to open the ball up. For switching I was thinking of using a magnetic reed switch - when a magnet is attached, the lights switch off. The only problem is that reed switches seem to be (a) made of glass (not ideal when the ball gets hit really hard), and (b) in a normally-open configuration - I'd need a normally closed one for this. As for charging, I have two ideas - one is to have two small metal pads on the surface of the ball to connect to the charger. This could be problematic due to forces on the ball during gameplay. The other more fun idea would be inductive charging. Like what you get in those fancy electric toothbrushes. One coil inside the ball, one outside. How practical is this? can it supply the necessary voltage and current to charge either a pair of NiMH batteries or a Li-ion cell? vik

frollard8 years ago
Okay, you have the idea perfect - use inductive charging, and an inductive 'remote control'. use the same circuit for charging as switching the circuit on and off, OR, while charging, the ball is 'off'. while not charging the ball is 'on', and have a portable charger that also acts to store the ball.
askvictor (author) 8 years ago
tempting; the main problem is the ball gets a bit of a trashing - I'd imagine the paint would come off or get dirty pretty quickly. There are glow-in-the dark street hockey balls around but apparently they aren't great.
VIRON8 years ago
How about painting the ball with the new long life green glow in the dark paint. I bought some on ebay and it glows a really long time and
possibly all night long if charged with fluorescent lights b4 a "game"
I'm currently experimenting with the idea of chemical solar nightlights,
but I suspect that infrared during sunset might be a problem since
it prematurely discharges the phosphorescence. They seem to work
much better as nightlights mounted near CFL bulbs and seem to glow
all night that way after the electric lights are turned off.
Green Strontium Aluminate or Europium phosphors can glow all night,
even brighter than RADIOACTIVE(!!!-???) Stuff.