Implementing a Rudder Sensor

A project log for OpenCPN Chart Plotter /w Autopilot and Waypoints

I am in the process of implementing an autopilot on my 42' Uniflite Aft Cabin Cruiser based on the original 1984 hydraulic steering system.

Timo BirnscheinTimo Birnschein 11/22/2019 at 00:500 Comments

In order to be able to safely control the servo pump for the steering system, I need a sensor to measure the rudder position.

I modeled a simple representation of the steering system and them thought about how to add a sensor to the structure. I have seen multiple people adding potentiometers using some levers and joints but I concluded that this is too complex and non-linear.

So I selected and downloaded design files from my new favorite gear provider: KHKGears

I then modified those gears to my liking and through them onto my 3D printer. This is an amazingly simple way of getting compatible gears in almost all sizes and complexities.

The sensor is a simple 5KOhm potentiometer in a 3D printed bracket, bolted to a plywood board. If I want to, I can simply add another sensor 90degrees offset of the first one to get a differential, redundant sensor signal. This might be necessary to really be able to trust this in the long run.

Currently, these gears and brackets are printing. Unfortunately, my Chinese supplier for the potentiometer has not managed to send me the parts since FEBRUARY! So I just ordered new ones, shipped from the US.