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Diving into underwater engineering

School kids in the South Island are constructing awesome aquatic technology from bathroom pipes and simple electronics.

Hope School students with their aquabots

At Hope School on the outskirts of Nelson, students have been building underwater robots and learning how to drive them, ready for the regional NZAquabots competition in November.

The pupils have been building the bots completely from scratch – from sawing and drilling PVC pipes to wiring up the circuit boards in the controller. The best part is that all the materials can be found in local hardware stores and don’t cost more than a few dollars.

NZAquabots founder, Amy Cornelisen at Ministry of Inspiration, says that the purpose is to give the students a taste of ‘engineering in action’, but also for them to keep honing their new skills.

"We give them a kit that they can modify to create other robots after they have finished their aquabot, so they develop a new way of thinking about designing and making things."

Students with their finished aquabot

First, the students cut metre-long PVC pipe into pieces of specific lengths and drill holes in them. Then they fit the pipes together using joining pieces and ‘thread’ two pieces of pool noodles onto the two longest pipes – creating a cube-shaped framework with a ‘fishing’ extension at the front. 

The school kids then cover the motor and propellers – used to move the bot via the handheld controls – in a thick wax to ensure it is waterproof, before pushing it into its cylinder housing and securing it to the bot using cable ties threaded through the drilled holes.

Last, the students connect the electronic components to the bot by stripping the outer sheath off a power cord and attaching the wires inside it to the motor’s electronics, with the other ends being soldered to the controller’s circuit board.

Putting wax on the motorStudents soldering  soldering wires

"I liked soldering the wires and putting the wax on the motors,” says Cheyenne, 11. “I've never done that kind of thing before and it’s inspired me to do more of it!"

Hope School principal Freya Hogarth says, "It's so great to see them problem-solving and working with tools we don’t normally use – especially the soldering iron.” 

While there are instructions provided, much of the work is self-discovery and using initiative. The students have to figure out their own order in which to assemble the bots. 

“I liked putting the pipes together because there were instructions but they didn't tell you everything so it wasn't too easy and it was a good challenge,” says 10-year-old Jonty.

Building robots

The students also have to work out how to avoid pitfalls and, if they have gone wrong, where. 

One student, for instance, had made the mistake of twisting together the wires connected to the circuit board, causing a short circuit and damaging the electronics in the controller. 

"It was me who crossed the wires – and I won't be doing that again!" says Edward, 10.

Fortunately there was a spare controller to hand, so Edward and his team were still able to test their robots in the school’s pool along with their classmates.

Shaving off the foam

At the pool, there is one more step to do before the robots can really move about in the water: whittle down the pool noodles. 

The students used a sharp craft knife to shave off some of the foam from the pool noodles, which act as buoyancy aids. The point is to lower the buoyancy so that the robots can dive down to the bottom of the pool, but not so much that they become too slow to reach the surface.

Getting the right balance could make all the difference in the competition, which is based on speed as well as performance.

"I learnt that the robot won't sink if you have too much foam on it,” says 9-year-old Allen.

The kids then spent the remaining time of the session practicing using the controls to get the robots to retrieve items from the pool floor, similar to the challenges that will be set in the competition.

Testing the bot in the poolRobot underwater

"I love how enthusiastic the kids are and how it all comes together beautifully at the end,” says Kathleen Flight at Ministry of Inspiration, who ran the session at Hope School.

“There’s often a moment when you've got 45 minutes left to finish the bots and you think they're not going to make it – but they always do!”

The NZ Aquabots competition runs on Sunday 5 November at Richmond Aquatic Centre in Nelson.

Follow NZAquabots via the Ministry of Inspiration’s Facebook and Twitter feeds.

Hope School students pulling faces

About the project

Ministry of Inspiration logoNZAquabots is run by the Ministry of Inspiration, with support from the Unlocking Curious Minds contestable fund.


Unlocking Curious Minds

Unlocking Curious Minds supports projects that excite and engage New Zealanders who have fewer opportunities to experience and connect with science and technology.

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