Re: Building a pool lap timer

On 2005-11-04, shez <adrianscerri@xxxxxxxxx> wrote:
> Hey
> I wanna challenge myself and make something that allows be to monitor
> my laps in the pool via a computer.

You want to use a mains powered appliance in the vacinity of a swimming
pool? ensure that the computer is correctly earthed and/or use an
isolating transformer or RCD ....

> I was think of something like a waterproof pressure mat hanging in the
> water, connected to a USB or Serial port connected to the computer.
>
> Any help would be great

maybe replace one of the buttons of an old mouse with wires leading to the
pressure pad.

from the safety standpoint and to keep the PC away from corrosive chemicals
it may be better tu use an air-filled pressure pad connected by a long hose
to a remotely located pressure switch connected to a old mouse (or directly
to pins used for the fire button on the joystick port etc...).

suitable pressure switches can be salvaged from many models of washing
machines (used in the water level detector)

as for the pressure pad, maybe a wheelbarrow inner-tube between two sheets
of stiff plastic (acrylic/lexan/fibreglass) etc

(the pressure switch could probably be made this way too)

Bye.
Jasen
.

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