Looking for hardware suggestions and enlightenment

We are trying to make a science fair project - to make a “robotic boat” that will go to several different waypoints to collect water specimens,

Here is what we have so far:
I think ArduPilot is a good way to go. I am able to plan and execute a set of waypoints using the simulator - it is possible to make special waypoints to make the robot boat trigger a set of outputs that we can use to fill a specimen bottle?

I also bought this from Amazon:

I am not sure if we need an IMU, or a flight controller - it seems like maybe we can use an Arduino for that, but a Naze 32 seem interesting, although I was hoping to not spend that much (not sure if I need an Acro or a Full to use the compass and GPS unit I already ordered). Since it is a boat, maybe an IMU is optional - it seems like a GPS and compass should be enough. Does a flight computer have relay outputs?

The other thing I think we will need, is some sort of telemetry. I have seen some discussions regarding SIK telemetry setups, and I know we need something with two matched ends (one for the ground control computer, and one for the aircraft (or boat for our case), but I don’t know how you would use a joystick if you wanted to over-ride the mission - does this normally plug into the ArduPilot computer - they normally have a transmitter, so maybe it just over-rides that laptop signal? Maybe the joystick is optional anyway - you can fly the boat by just clicking on the screen.

I think we can use a cheap CNC motor and controller that we use a lot at work, although we usually use position control, not speed control. I know how to drive this quite well with an arduino. If we used a pair of them, then we maybe don’t need a rudder. Not sure if you can drive these direct with a flight controller, or if these use a different controller entirely. I think we have a couple of tiny servos laying around that we can use for his collection device, and we will need to get a small water pump (and relay driver of some sort) too.

Lastly, I see where a raspberry pi is used onboard - does ardupilot go on there? If I use an arduino to control the motors and IO, where does this fit in? I have seen this arduino AHRS, but not sure if I can use this instead of a flight controller, or if it will work with my hardware, or what. GitHub - STMPNGRND/ardunav: Open Source AHRS development platform and Algorithms

This is where I am trying to work through at the moment…


you need to have a look at flight controllers that are compatible, naze controllers are not supported in any way, APM controllers haven’t been supported in years so avoid even if they are cheap, your best option for something cheap and integrated is something like a omnibus f4 pro.

It was interesting many years ago and in any case Ardupilot won’t run on it.
These will ArduRover Stable

No, you also need a Flight Controller. The RPi is the Companion Computer.

IOW, you need a Flight Controller.

So what does the companion computer do then? Does a part of ArduPilot run on it? Or is it strictly for things like having a video feed? If so, does it intercept the ArduPilot messages and then pass them on to the flight controller?

Thanks so much for the help!

Seems like BeagleBone Blue is my favorite option from the list - I recall seeing the list now.

Thank you for the information!

I’d caution you against the Beaglebone Blue - it can be exceedingly difficult to set up and isn’t quite as fully featured as you might think. ArduPilot takes a large portion of its CPU time, making companion processes sluggish.

I think you should watch some videos on the subject first. it will give you a general idea for whats required

You are out over your skis. Start here Rover

Very good information, thanks

So I decided on a Matek 405 HDTE 3-12S, and I also got a FrSky R-XSR receiver (the new version that you can un-invert). Now I just need to dig for the part that goes on the laptop side (is it only through a controller?), and/or try to use one of the WiFi modules listed here: Telemetry (landing page) — Rover documentation

If your not going far the wifi modules are ideal for rovers.

I use ESP8266 radios and SiK radios. The former are cheap and good to ~100m max.

What Transmitter do you have for that R-XSR?

1 Like

Good to know - I just ordered an ESP8266 from Amazon. I do not have a transmitter for the R-XSR. I do have 2 or three transmitters, but I may have hacked them so I could have a cool joystick for another project. It may be possible to resurrect one of them from the dead, but I haven’t inspected them recently.

For the purpose of a science fair project, we can limit our mission to WiFi range - that will also keep costs down, but after the grade, we can still use the hardware for other cool projects.

Might be worth skipping the FrSky RX/TX hardware in favor of ExpressLRS. It’s generally cheaper and has proven rather easy to set up with excellent range and live telemetry.

There’s nothing “wrong” with the R-XSR, per se, but FrSky hardware is notoriously painful to ensure matching firmware and can sometimes be frustrating when setting up telemetry - I am in the process of transitioning away from it as a result.

1 Like

“Frustrating when setting up telemetry” You’re being kind. I’m microseconds from dumping FrSky here, for all the reasons. End of rant.

1 Like

I’ve had a great deal of success with it (FrSky) for several years now, but I’m tiring quickly of continuing frustrations. ExpressLRS has really impressed me as a replacement.

So, what’s the plan to use the R-XSR if you don’t have a Transmitter to bind with it?


That is good to know, thanks!

Hi! I created a tutorial for Hacking 4 Oceans @ UCSD to help people starting with Arduboat. It covers everything from the hardware to the software. Hope this helps!

1 Like

Great link, and cool project. Hey - we plan to use two 12V 1.5A DC motors to drive this thing in “sled” mode (we plan to use two attwood V500 bilge pump motors). What kind of driver do we need? Is there a driver built in to the Matek 405 HDTE 3-12S? I thought there was something, but the documentation I could find on the Matek was limited (the matek website was down, so all I could find was a top-level getting started guide). The quick start guide showed an ESC controller (it was one ESC that controller 2 quad copter motors). I have driven these motors with an H-bridge and PWM signal long ago, so I don’t know if an ESC would do the same thing.