Throttle encoder

A few weeks ago I bought a zero turn mower, which I’d like to automate.

The basic idea is to keep the mower controls as original as possible.

In essence, the mower controls: hydrostats (lap control arms), throttle, choke need to be ‘electronified’… ‘sensored’ (encoded) and actuated via servos. When switching from manual to automation the servos would get their signals from a pixhawk.

The first idea was to run the throttle cable into a black box with wire encoder, and servo which actuates the throttle. Hence, no mod to the the original cable.

After looking at all sorts of ways of encoding angles, linear motion, etc. with angle sensors, incremental encoders, rotary encoders, magnetic tape sensors, etc. pretty much all day, I could not find a reasonable approach.

Then I thought to hell with it… and simply use a waterproof rotary encoder for the throttle… like a volume knob, and ditch the throttle lever altogether.

The choke can be a push button with an LED; press once and opens the choke half, press twice and it opens full, with an electronic reset once the engine has turned over a few times.

Is my latter idea to outlandish?

Has anyone added an encoder to a throttle lever?
Was the outcome presentable / acceptable?

I liked the idea of magnetic tape and sensor, as these have 0.1mm and better resolution.

If I only has the ability to 3D print (sigh) :slight_smile:

Alright, after speaking with some mower guys, I am replacing the throttle and choke with rotary encoders. The guys see no issue with operating something that resembles a volume knob.

The benefits are many:

  1. removal of mechanical inputs for throttle and choke = huge simplification, given that servos are required for automation anyway.
  2. software will now provide future improvements (like a Tesla); e.g. auto-reset choke after engine has started. Set choke based on engine temperature.

The rotary encoders go endless. E.g., A LED bar shows amount of throttle.

Anyway, I see only benefits :slight_smile: