LEGO ROV without a tether

[Brane] built an underwater ROV from LEGO mindstorm parts. Look closely at this image and you should notice something missing. The tether that normally carries power and control lines from an ROV to the surface is missing. This is a wireless solution that lets him control the device using an Xbox controller.

The video after the break shows about five minutes of test drive footage. [Brane] has a big aquarium in which he can test the thing. Since he put it together as his senior engineering project at University it’s likely that this is a testing facility at the school. Here’s the little we know about the hardware: It’s using NXT Mindstorm parts to control the motors, with a sealed chamber for a battery. Connectivity is provided by an XBee module with an NXT adapter board called the NXTBee. A laptop with its own XBee module makes up the other end of communications. Right now [Brane] uses an Xbox controller connected to the laptop, but a standalone device would be easy to build by hacking the XBee and controller together directly.

[via Reddit via WonderHowTo]

Comments

  1. itwork4me says:

    Quite a nice bit of work.

  2. Rob R. says:

    Awesome project!!

    If I may, how did you waterproof the NXT and the motors?

    Are you using the pneumatic system for legos for a ballast?

    Either way, that is pretty awesome for some lego parts! BTW, I have used LeJos as well, it’s much better then the graphical programming environment that they give you to start, but I guess it’s for non-programmers to program their robot with.

    • ffmurray says:

      Rob,
      if you look closely there are vertical thrusters that take care of the depth adjustment, on most ROVs there is no variable ballast, the ROV is built to be neutrally buoyant or even float a little bit. All of the depth adjustment is done by thrusters. I dont know for sure, but in freshwater generally there is no need to waterproof motors, both brushed and brushless seem to do pretty well. Ive even heard of people successfully using unprotected motors in saltwater and just rinsing them off with fresh after the dive.

  3. Joseph says:

    This project is well built. Don’t ROV’s have tethers because radio signal cannot travel more than 15 feet in water under best conditions.

  4. jc says:

    correct me if I’m wrong but wouldn’t range of any wireless signal under water suck very hard ?

  5. camerin says:

    this solution will only work in shallow water senerios, that is why we teather things, even the navy uses a teathered com antenna for comunications over any realy diatance. good project though. simple but good.

  6. cirictech says:

    2.4Ghz under water Is going to have a epic ton of loss.

    But it is really cool that this works!

  7. RecentEngineeringGrad says:

    This is a cool project but I cant believe that he got away with doing a senior design project using legos. Lets see that fly after graduation. His university failed to understand the purpose of a senior design project and in the end fail to prepare him for life after his degree.

    • Paul says:

      Explain why LEGO is an inappropriate senior design project material. He’s displaying a concept utilizing materials that are readily available in within his budget. He succeeded at building and displaying the point of his project.

      I highly doubt there was a requirement to build this out of steel or some other manufacturing process. I argue that there is no need for him to reinvent the wheel by designing a whole new product just to showcase a project that has nothing to do with the building materials.

      To add to this, if he used materials he had laying around then he could put the money had where it was needed, thus staying under budget. This is exactly the skill necessary for life after college.

      So, I’m not really sure how building with LEGO shows any deficiency on his learning, what his school taught, or his ability to move on after college.

      • Totally agree that you have actually succeeded far and beyond the requirements by utilising of the shelf components, This skill is essential when working in a “real” ROV environment, the negative comments from the recentgrad just proves that there inexperience and non adaptive thinking will place them well behind a McDonalds counter.

  8. Rick says:

    unfortunately the whole point of a ROV is to allow an operator vision and/or the ability to interact with the ROV’s environment. the sub also would need at minimum a wireless video feed back from an on board camera in order to be anything more than a RC bathtub toy. Get the Xbee to plex in video from a sub and then we’re talking. Me, I’m staying old school and keeping an ethernet tether for command/control/telemetry for my current ROV project. :)

  9. wretch says:

    Well done, but it needs torpedoes, harpoons, lasers or something. Come on, I want to see some wildlife dying! BWAHAHAHAHAHA!!!

  10. Miroslav says:

    He can use Extremely Low Frequencies for extended range, like submarines. Otherwise, when he tries his ROV in a lake or river it will quickly get out of signal range.

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