Controlling speed of brushless motor with wired connection to ESC (No RC)

I’m in the process of designing a small efoil boat powered by two efoil - type motors and ESC’s . Since I will be sitting in the boat, I would rather control the motors using pedals , knobs or levers rather than RC. I’m trying to figure out how to do this - it appears that using servo testers connected to the ESC’s may be one way to possibly do this. I’d appreciate any suggestions/advice.
Thanks in advance

Depends on the ESC, if you use a VESC, you can also use an analog 0-5V signal. You could use an Escooter thumb throttle or just a potentiometer voltage divider to generate that signal.


Thanks , Daniel - that’s very helpful - for some reason I didn’t think about how electric bikes are controlled !. It also appears that by connecting a servo tester between the thumb throttle and an ESC (as opposed to a VESC) this will work also, so my problem should be solved !


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Hello Eric,

I am building something similar. Interesting. What are your plans? If you use vesc you can use a thumb throttle control directly connected. If you use standard esc it is either Servotester or arduino.

This will be my frontwing setup.

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Hi - I’m simultaneously building a 3’ RC model and designing a full-scale version. Planning on using surface- piercing foils front and back, as I think that’s probably going to be a more stable configuration than totally submerged foils, and to some extent “self - balancing” . Was originally going to use a single brushless motor with propeller for power, rotating the motor and strut for steering capability. Decided that led to too many complications with seals etc., so now am planning on two motors with independent ESC’s and throttle controls so I can hopefully steer by varying the thrust of the two motors. Will use kitefoil struts at the rear, and some airfoil - shaped carbon fiber I picked up for front struts, and am planning on 3D printing and then fiberglassing all foils - hopefully they’ll be strong enough.
Am building it with wings and “tailplane”, and will cover them and the upper “fuselage” with flexible solar panels after some test flights if it seems to work. Probably have enough area for 2 or 3 hundred watts of solar power, which will extend battery range by a little , maybe :slight_smile:

Even if it doesn’t work it’s a fun project…


Wow. Do you have pictures of the RV model?

Have you seen this project? Looks quite similar to what you intend to build.

I hadn’t seen that before - very interesting ! Body is a little less exotic than my design, but foils are more exotic - making those curved front foils must be quite difficult , and not much leeway for modification if things don’t work properly.

Not currently - it’s mostly built, but in pieces - also , I need to put a layer of fiberglass over the PLA for extra strength, I’ll post a photo when I get it put together. For anyone trying to build something similar, here are a couple of useful books :


Only just realised that you had a link to your Instagram page - that’s quite a fancy control system - very impressive ! I was a little worried about controlling direction using the front foil , so decided to go with the two motor setup, although currently my model is designed / built with the motor on a rotating strut at the back. I’ll probably find that the turning radius is about a kilometer on the full size version, but I’d rather be conservative initially (I’m 79 and not sure my body can survive too many on-water disasters :slight_smile: ). I’m planning on controlling the angle of attack. of the front foil /strut using a joystick, but will use a mechanical connection rather than motor-driven.