Underwater Propeller - Waterproof Trigger Button

Hi there,

I'm in a project where I need to build an aquatic propeller but currently I have a problem regarding the button.

I need a waterproof button or potentiometer (pot preferably) to actuate on the ESC that controls the brushless motor. After trying to search for a potentiometer that was IP67/68 compliant I found that the prices were too high for my budget (around 70€) which is justified by the fact that it was industrial products.

I tried to search for more options including magnetic buttons but found nothing of interest.

Does anybody know of any cheap way to accomplish this? When I say cheap I say maximum 20/30€.

TL:DR : I'm looking for a cheap waterproof potentiometer or button (IP67/68 compliant)

Can't you make your own button with a hall sensor?

Grab a sensor, solder the wires and seal in silicone. Now you just need to use a magnet to switch it. There are different kinds of hall sensors, see the differences and pick the most appropriate...

Also, I never used but you also find analog hall effect sensors so you could use as potentiometer by changing the magnet distance.

Thank you for your reply.

I actually thought about that idea but the trigger mechanism puzzled me a bit.
I was looking for a trigger like mechanism similar to rc car controllers with the magnet inside.

Another question: will the silicone and the fact that it will be underwater affect the magnetic field? Will this be a reliable solution?

Just give a try... Use those super strong magnet, but I can't see why it wouldnt work. The water shouldn't be a problem.

The mechanical part can be anything thet will move the way you need.

Btw, what's the switch/trigger for exactly?

musskopf:
Just give a try... Use those super strong magnet, but I can't see why it wouldnt work. The water shouldn't be a problem.

The mechanical part can be anything thet will move the way you need.

Btw, what's the switch/trigger for exactly?

Thank you I'll sure give it a try. The switch will be connected to an Arduino based board that will operate an ESC. The trigger will control the brushless motor thrust

Have you consider wireless control?

musskopf:
Have you consider wireless control?

It is going to be a hand-driven device to use underwater attached to your arm so wireless control is out of consideration.
I've tested the hall sensor yesterday but the results weren't satisfying. I had a very tiny voltage variation on the sensor with the magnet pretty close, I was using one of those magnets to stick on the fridge.

I believe it could be due to the angle I was positioning the magnet but also due to the magnet quality (maybe it's not that strong?)

What hall sensor are you using? What voltages areyou getting?

Also, you can ways use an OP Amp, the important is the voltage variation to be consistent.

Another option is to have some sort of encoder, can be hall or optical, just leave the electronics inside and the encoder disc (magnets or mirrors) outside.

I'm using the SS49E Linear Hall Effect Sensor and I'm feeding it with 5v.
In the code I'm putting the voltage in the Serial Monitor getting a typical value of 512 (which is expected since with 0mT the sensors outputs half the supply voltage). When I approach the magnet it starts to react when I'm approximately 1cm away from the sensor and the lowest value it output was 470 something. An yeah it is pretty consistent and stable.

This doesn't bother me since I could solve it with a mapping, what bothers me is the fact that it only reacts when the magnet is pretty close.

Yes, those hall sensors have a very small sensing area. Try one of those Neodymium magnets...

Also, any reason you're not getting to 0? Have you enclosed everything in silicone or only the pads? You can make a setup using a fine threaded screw and nut, so you have good control of the approximation.

musskopf:
Yes, those hall sensors have a very small sensing area. Try one of those Neodymium magnets...

Also, any reason you're not getting to 0? Have you enclosed everything in silicone or only the pads? You can make a setup using a fine threaded screw and nut, so you have good control of the approximation.

I'll order some of those. It is a normal not to get 0, actually according to the datasheet you can get minimum 1V under a 5v supply voltage. When there is no magnetic field you get half the supply voltage (in this case 2.5v which is converted to 512 by the ADC).

I didn't test with an enclosure, just tested on a breadboard and got those results. I'm thinking of making a 3d printed trigger with a small enclosure for the magnet. As I press the trigger i move the magnet closer to the hall sensor, that's the goal.

You might want to contact silent submersion or suex and buy one of their trigger assemblies.