Where can I buy this movement?

Go to the auto parts store, buy a gauge that uses that movement, then take it apart.

Have you priced them? Try $90 :-(

Might have to try winding my own ;-) ...Jim Thompson

Den tirsdag den 6. december 2016 kl. 23.40.44 UTC+1 skrev Jim Thompson:

Thanks, Lasse.

I wonder... is there such a thing as a two-pole PM motor? They're in textbooks... real life ?:-) ...Jim Thompson

Alternatively: Is there a ready-made stepper type assembly that I can feed bits defining the angle and have the rotor go to that angle? ...Jim Thompson

Look for GM instrument replacement steppers. They are incremental, of course, so you have to zero them then step to the desired angle.

--sp

Radio-Controlled servo motors might fit the bill...

John :-#)#

if used as is they need to be powered all the time, they tend to move when powered up.

but i guess you could just open one up and connect directly to the motor and potmeter

Any way to control them without a uP ?:-( I speak only analog... I farm out digital... this is a G-job. ...Jim Thompson

movement. Can that be had? ...Jim Thompson

eBay or Craigslist may net you some joy.

Sure, just get a big compass. Treat it as a compass-repeater problem.

A permanent magnet, four N poles, four S poles made from iron, and a little AC applied selectively to the arms (to cause saturation) will steer a compa ss nicely.

Don't think so. Even the Sail winch servos are only 140 degrees.

Cheers

can

hen powered up.

r and potmeter

If Jim goes to the trouble of using a stepper motor to do his job, 360 degr ees is a given, but he will have to work out a way initially setting an abs olute orientation.

lists a rotary encoder with a 4-bit absolute output - 22.5 degree steps.It' s a Grayhill 25LB22-H and not all that cheap, but there are lots of parts lik e it around.

The last time I saw one of those I had just built it from nails and bell wire.

Many of the aircraft ADF indicators are using a two-phase motor to turn the pointer. Another possibility is a resolver (two-phase synchro) with rotor fed with DC.

Jim Thompson prodded the keyboard with:

Would a Selsyn pair work. Basically a pair of motors connected so that when one moves/rotates the other one follows it.

A motorised volume potentiometer

next you'll be wanting a linear track on the pot...

Sure you can. Servo City sells some with continuous rotation, even. RC servos rock.

Cheers

Phil Hobbs