Let's Make Robots!


Mapping water depths in lakes
whirligig.pdf2.66 MB

I might be breaking some LMR rules, but this robot was built on my spare time while funded by the University of Oslo  and my employer APPLY Sørco, covering the hardware cost.

This robot was built to make bathymetric charts of lakes in Norway. It was initiated by my brother who is a professor at UiO. Totally disregarding my lack of engineering skills, an over estimating my programming / electronic skills he commissioned me to build ‘Whirligig’.
The robot navigates according to GPS coordinates stored as waypoints on an onboard SD card. Logging GPS and water depths along its rout (every 10 sec.). The estimated runtime is 24 hour before it needs recharging of the 7 batteries.

As you can see from the attached PDF file (in Norwegian only, sorry) am I working on a second version of this robot. This time using solar panels and a catamaran hull for more flexibility on payload and stability.

This is a block diagram of the control system


The original plan was using an ardupilot, but I ended up with using a regular arduino and building my own navigation software.

Google sketchup of the design


Some images from the hull build





All the decks laid out showing the position of motor and instrumentation batteries


Testbed for instrumentation and navigation check.


Instrumentation mounted in top deck and lid.


Waterproof box enbeded in the lid. Holding SD cards for waypoint and log data, GPS and charging plugs.


My daughter doing water intrusion test :-)



I am currently building a Mark II version with a complete new hull. This version will be self-contained with power from solar cells and upload data and getting waypoints via a GPRS shield.
This version will also have a full-size  computer onboard, the fit PC2.


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 I used to live on a lake and I always wanted to make an automatic camera that would take pictures of fish jumping.   If you mounted a motion detector camera on your robot, I bet you could get some fantastic shots of fish jumping.     I always noticed that the fish jumped at dusk when the sun went down and the water became calm.   I think it was because it was a good time for insect to go out and lay their eggs in the water and maybe the fish then did not have to deal as much with internal reflection from the surface of the water.  I can think that might be a great tool for collecting information on water quality around an oil spill.


This is a very great project !!!!  good  job !


It's just a great project. For your "lack of engineering skills" did you a very impressive job. Well done.

" Totally disregarding my lack of engineering skills, an over estimating my programming / electronic skills he commissioned me to build ‘Whirligig’."

It's wonderful what people can do when they want to do something, even if they don't know how to do it.

What you've shown is, despite not knowing where you're going, or really how to get there, you applied yourself and did it.

What you DIDN'T have was people telling you that you couldn't do it, or that the project was beyond your expertise - in fact, you had the opposite, and I think that was probably important.

Wow!! That's master piece of work! Really pro~ I hope I could work with people like you. This is a fun job and learned a lot too!

Amazing project.
Wow, nice boat! I would really like to know how you are going to tackle the GPS navigation via PC once you have that setup? On the Mark one the stabilizer looks really big, any reason for that? Looks like it will cause a lot of drag?
Handling the GPS from a PC will probably be much easier since the Arduino has a limited string handling  capabilities. The information from the GPS is just ASCII characters sent over a com port in accordance with the NMEA protocol.

The large center hull holds all the motor and instrumentation batteries. Giving it at total weight of 50kg. The aim was to set it as low in the water as we could so it wouldn’t drift from wind or weather.
The hull is completely watertight so water can flow over it if it is hit by a wave.  

Makes sence!

BTW thanks for mentioning the Fit PC2. I was looking at mini computers for some ideas and this is a good one.

You mentioned wireless communications using remote desktop. You could use a USB cellular stick for laptops to get a longer range depending on the cellular network at your house or at its final location.