Re: help with pump control

On May 7, 7:12 am, MooseFET <kensm...@xxxxxxxxx> wrote:
On May 7, 12:13 am, Roger_Nickel <r...@xxxxxxxx> wrote:



On Sun, 06 May 2007 23:07:38 -0700, rpang wrote:
Does anyone have a solution to this problem?

My solar driven water pump is about 1200 feet line-of-sight from
the tank it pumps into.

There is no wire going between the two and it would be no fun to
place such a wire.

The pump controller has a connection such that a short across it
turns off the pump.

Thanks for any help!

Radio or laser link?. A transmitter intended for radio
controlled models would work if fitted with a directional aerial. If you
have line of sight then an optical link using a modulated laser pointer
is theoretically possible but 400m is a long shot.

I think that aiming will be the hardest part with a Laser. You could
get that sort of range with a modulated light bulb. Here's what you
do for either laser of lightbulb:

At the transmitter end you make an open ended box, lets say 10CM on a
side. The insides of the box are painted with the flattest black
paint you can get. The light is placed at the center of this box.
This makes an easy target to line the receiver up on.

The transmitter pulses the Laser at, lets say 500Hz. It uses a
crystal oscillator for timing.

At the receiver, you use a telescope to make the image of the inside
of the box fall onto a photo detector.

The receiver electronics has an amplifier and lets say the dreaded PIC
or an 8051 with ADC. The amplifier contains a modest band pass
filter. The micro runs on a crystal so that its timing is very good.
Creating a bandwidth less than 1Hz isn't hard to do in a micro.

This rings my bell for its' complication alone, perhaps someone could
flesh out the hoary details. Yes, unfortunately, there must be
details!

.

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