Frank, my thoughts are that if the stroke of the actuator piston was say
10cm you'd
need to space your unit out to 10cm wide to match it. This will require a
magnet 5cm long
to bridge between the central & outer reed switch.
As the magnet moved off the outer reed switch it would be registering
centre position
over a wide range of movement.
Jens unit shouldn't be too hard to put together, & if you just want a
linear potentiometer
the magnetic membranes look a good option that will give you 10 position
accuracy.
Alan
----- Original Message -----From: ShellyDalg@aol.comSent: Thursday, March 18, 2010 8:01 PMSubject: Re: [PSUBS-MAILIST] Rudder angle indicatorI made a little sketch for a position sensor using three reed switches and 4 wires. When the magnet is over ONE reed switch it lights ONE LED. When the magnet is over TWO reed switches it lights up TWO LED's.This is the mid-point between the two positions. This could give a total of 5 positions.......Full left, half left, center, half right, and full right. When operating the rudder control it would be easy to tell how far it has turned by how many and which LED's are lit. It would require a 4 wire thru-hull but wouldn't use any electronics. The reed switches are TINY glass tubes and would be easy to seal up as a unit in epoxy. By using single strand wire there would be no leakage.Frank D.
