Let's Make Robots!


Measure water depths in lakes
Bilde.jpg881.9 KB
MarkII_LOG_microSD.zip2.73 KB
MarkII_NAV_microSD.zip5.11 KB
DELFTship_linesplan.pdf159.55 KB
Mark_II_versjon_1a_mod.zip9.02 KB

This is Mark II of the Whirligig project http://letsmakerobots.com/node/16995 code name SEA RENDERING (it’s not actually a code name, just an anagram for my name :-) )

The purpose of this robot is to have it log water depths along a predefined set of waypoints. It stores its data on memory sticks or on SD cards. The estimated runtime is about 24 hours and with a top speed of 3km/h it will travel roughly 72km. With a log entry for every 10m this would give us over 700 depth measurements   with full GPS reference.

Most of the control system has been moved from the original Whirligig to save cost and time.

The hull was designed in the free version of DELFTship http://www.delftship.net/ and built this winter. With the split mould I can produce a second hull in matter of days.

The original plan was two hulls working in pairs as a catamaran with a solar panel on top. This can still be done but two robots working independently we can cover a larger lake on shorter time.

Some images from the hull build

Adding fiberglass to one half of the mould

Mould completed

The first casting

Here are some pictures from the complete robot


Polymorph beddings for the batteries

Control system

Some electronics in the lid

The waypoints are entered using my adaptation of the Ardupilot tool. A great application that lets you interactively add waypoints to your list. This list is then copied onto the SD card and the robot is ready to run.

I run this routing 3 times and this is a GPS visualization of the log. The green markers are the waypoints.
(one of the log files are attached)

My brother (a professor at the University of Oslo) that will be using this robot, then run these 3 logs in something called  "Thin plate spline" http://en.wikipedia.org/wiki/Thin_plate_spline to see if the depths we logged made sense. And this is what he came up with.

All in all this project seems very promising.

Update 28/6-2010

After having had some problems with the VDIP1 USB interface I decided to go for the microSD shield from Sprakfun http://www.sparkfun.com/commerce/product_info.php?products_id=9802 .
Now the whole thing looks much cleaner and is probably more robust.



Update 11/7-2010

This weekend my brother and I went to the lake ‘Riskedalsvatnet’ to do a full scale test. The full waypoint routing had 337 waypoints and a total length of 18,1km.

The traveling speed of the boat is about 3km/h so the mission should have been completed in about 6 hours. As this was the first full scale test and we had some uncertainties on where the shore line actually where, we decided to split the trip into 3.
This is the first segment of the mission.

This is how the boat run

And this is an Dr.Depth rendering of the depths we got.

After all segments where completed this map was generated in Dr.Depth

A full size map in b/w is attached


UPDATE 14/7-2010

Added the Arduino sketch if anyone want to have a look.

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This might be a stupid question but I don't understand how I'm supposed to print the linesplan in the correct scale. Even better would be if I could print the correct scale but splitted in several A4 papers. Is this possible?

The PDF file is just an A4 copy of the drawing. If you want to build the boat you should install the free software that I used to design it in from http://www.delftship.net/ and download the full design file from the Mark_II_versjon_1a_mod.zip file that is in the start of this post. Then you can change the design in whatever way you want.
Keep us posted if you’re embarking on the project of building something similar.
Best of luck!

which GPS module did you use?

I think it was this one https://www.sparkfun.com/products/465 
(after all, I built this 3 years ago)

Hi there, this is a "WOW" project and its cool

I guess I have to start saving some bucks to start a similar project :)


you project is cool. i want to build one. can i get the format you save the data to SD. and a link for the planner software.



I just save the NMEA sentences as they come from the GPS and transducer.
'planner software' ? what do you mean?

what i mean is the waypoint planing and feeding to boat to run it. how do you do it.

OK. The waypoint software is my version of the Arduipilot tool. It is written in C#
And if you put a post here on LMR of a working boat, I'll send you a copy of the software.


can i get a sample waypoint file you store in SD card and load to the boat as navigation data. So i can prepare according to my cordinates and experiment it. later will upload th project so you can provide software later.

I am very new to these but trying to catchup with the help of people like you.