|
Frank,
I've only just googled this, but it seems to have potential.( It's
the 2011 option)
"Magnetic membrane potentiometer" It's a flat wafer thin potentiometer
& there are magnetically
operated versions. I'm thinking you could encase it in an acrylic sleeve
& operate it with a magnet
of sufficient strength sweeping along it. They talk about "rotary" devices.
If these are potentiometers in
a circular form they'd be ideal. It would be just two wires through the
hull & if you could wire it to a suitable fuel
indicator gauge you'd have an accurate position indicating system.
The membrane potentiometers I looked at sell for round $10-
Alan
----- Original Message -----
Sent: Tuesday, March 09, 2010 6:50
AM
Subject: Re: [PSUBS-MAILIST] Rudder angle
indicators
For a sensor to detect rudder angles or dive plane angles, Minnkota and
Lenco have the setup built into the trim tab actuators/switches. The system is
a little pricey though. The Minnkota actuators with a 4 inch stroke are $259
for the actuator alone, and another $80 for the switch with LED graph.
As an alternative, it should be possible to use the idea suggested by
Alan. He mentioned a magnet coupled to a simple "string" of magnetic switches,
wired to an LED display inside the sub.
In my application, it could be set up on the linkage controlling the dive
planes or rudders. The number of wires would be determined by how many
magnetic switches are used. I'm thinking 5 would suffice. One for center and
two on each end for half way and full stroke. The whole thing could be potted
in epoxy making it waterproof. Replacement of any individual part would
be fairly inexpensive. The magnetic switch "strings" could be fabricated and
kept as a "spares", the magnet attached to the linkage with a screw, and a
small epoxied thru-hull. The internal display is the same, Low tech and cheap
to build, easy to replace. Keeping it simple is the key to low cost and
reliability. I bet you could even find the magnetic switch "strings" and
internal LED graph parts as off-the-shelf items. You'd have to seal them up (
potting in epoxy ) your self and make a mount specific to your
application, but replacing a blown part would be easy.
Frank D.
|