Waterproof, wireless transmitter throttle control inside a 1.25" diameter tube?

Hi all,
Im looking for advice or help in design and fabrication of a wireless, waterproof throttle control transmitter.
The throttle will control a RC PWC and will need a receiver that can interface with a 300amp ESC.
The entire transmitter needs to fit inside a 1.25" diameter tube with the exception of the throttle control trigger which will be attached to the outside of the tube. (Think standard RC throttle trigger connected to a tube) The tube will be carbon fiber and will be subject to water exposure and will at times need to be submerged underwater.

Is this something that can be done with Arduino?

Im really looking for an Arduino expert to help me with this aspect of my project. Im willing to pay a qualified person to work as a consultant/engineer…

How about putting the controller inside a sealed enclosure with a flexible bellows so that the throttle mechanism can be operated from outside the enclosure?

I'm not sure what you mean by putting a bellows between the controller? I was intending to use some waterproofing enclosure of some sort, waterproof heat shrink will probably suffice. It seems the tricky part is getting all that stuff to fit in a 1.25" diameter tube. How can it be done?

littlejetboy: I'm not sure what you mean by putting a bellows between the controller? I was intending to use some waterproofing enclosure of some sort, waterproof heat shrink will probably suffice. It seems the tricky part is getting all that stuff to fit in a 1.25" diameter tube. How can it be done?

What I think PeterH was hinting at is that the trigger is a moving part and will be difficult to make waterproof. He was suggesting a way to make the trigger mechanism waterproof. The other thing to consider is how you will power the device. Batteries need to be replaceable and you don't want to have to cut the waterproofing to replace the battery. Rechargeable batteries need to be recharged and power jacks aren't (usually) waterproof. Have you looked into the possibility of using induction charging, as used on some electric toothbrushes? Is your tube 1.25" INSIDE or OUTSIDE diameter? If it's 1.25"outside dia., what's the inside dia.?

The internal diameter is 1.25in, outer diameter is 1.5in.
I was thinking I could use the same type of throttle as on a Jet ski, linked to a wireless transmitter instead of direct to the engine.
Some type of pull trigger. im planning on using lifepo4 batteries or similar and having a small recharging plug with a waterproof cover that is removed for charging.

Im hoping to get some recommendations on components or maybe some reference to similar projects out there?

Im not tied to the trigger throttle either, currently considering other options for throttle control in wet and sometimes submerged conditions.

There is a product out there called the Fiik that has a wireless throttle.

I basically want that skinnier and waterproof!


You seem to be describing a system with three separate components.

A radio receiver which controls an ESC.

A radio transmitter inside the tube.

Some unspecified throttle input control on the outside of the tube.

What sort of connection are you providing between the transmitter and the throttle? I mean, is there a hole in the tube so that you can connect a mechanical push/pull rod, or what?

I can almost envisage a solution consisting of a force sensitive resistor, Arduino to read the FSR, radio transmitter to send the value from the FSR to the receiver, whole thing enclosed in a waterproof cylindrical sleeve (section of bike inner tube cut to length with the ends sealed?) pushed inside the tube, with a throttle lever that presses through the enclosure onto the FSR. None of the components would need to be bigger than 1.25" diameter and I think it could be made robust. But I don't know if you're willing to make a hole in your expensive-sounding carbon tube for the throttle mechanism. I also don't know whether a carbon fiber tube shields radio transmissions. If it's practical for you to package the trigger mechanism and transmitter entirely on the [u]outside[/u] of the tube, this would be easier to design. But without knowing what the tube is for, I have no idea whether that is feasible.

The tube is an SUP paddle. I dont see a problem bringing the trigger and transmitter to the outside of the tube as long as they can be secured adequately. (fiberglass & resin)

the length of the paddle's tube is around 6 feet so there is plenty of length to fit components.

I hadnt thought about carbon fiber shielding the radio transmissions but upon doing a quick google search, that appears to be the case. Since carbon fiber is a conductor, it is therefore a RF shield, so the transmitter antenna will have to be on the outside of the tube...

@Peter, Thanks for your comments. Would you be interested in helping me complete this project as a subcontractor? Im sure we could work out a mutually agreeable amount/rate for your help if you're interested.

No, I don't have time to take that on, thanks. It's an interesting project, though, and it will be interesting to see how you get on.

I suggest you get the electronics and wireless stuff working as a mock-up to check whether it's actually going to be reliable enough for you before you get too far into packaging it. I mean stick the electronics in a bag, tape it to the paddle, stick your thumb over the pressure sensor and just see whether it controls the motor adequately when you're waving the thing around in a wet environment.

Given the application, I guess the throttle assembly will be in danger of getting bashed on things so it would probably be better to look for a flush push button to operate the pressure sensor, rather than a throttle lever. I think you will have to mock things up and see what works for you, but I suggest you try adding a slim housing into the outside of the tube, somewhere near to where you normally grip it, to contain the electronics. I'd look to make the housing with the section of a crescent moon that was a close fit to the tube, have a flexible water tight enclosure inside it to contain the electronics, and some way to remove it from the tube for charging. The biggest component it would need to hold would be the battery - perhaps a few AAA cells? If you include a QI wireless receiver you could recharge it inductively, avoiding resealing issues.

If you can't package it outside the tube then it should be easy enough to fit the electronics inside, but you'd need to provide holes in the tube for a pushrod between the throttle control and the pressure sensor, and another one to let the transmitter aerial out, and presumably both of these would need to be sealed. It feels like a neater solution, but harder to make and harder to maintain.