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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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.



This is part of a waypoint file.


H 000 058.871330 005.810080
L 001 058.871780 005.811590
W 002 058.871330 005.810080
W 003 058.870890 005.810190
W 004 058.870830 005.809340
W 005 058.870320 005.808600
W 006 058.869820 005.807860
W 007 058.869880 005.808720
W 008 058.869440 005.808840
W 009 058.869380 005.807980
W 010 058.868930 005.808100
W 011 058.868990 005.808960
W 012 058.869050 005.809810
W 013 058.868610 005.809930
W 014 058.868550 005.809080
W 015 058.868490 005.808220
W 016 058.868430 005.807360
W 017 058.867980 005.807480
W 018 058.867540 005.807600
W 019 058.867100 005.807720
W 020 058.866650 005.807840
W 021 058.866210 005.807960
W 022 058.866590 005.806980
W 023 058.867040 005.806860
W 024 058.867480 005.806740
W 025 058.867920 005.806630
W 026 058.867860 005.805770
W 027 058.868370 005.806510
W 028 058.868870 005.807240
W 029 058.869310 005.807130
W 030 058.869250 005.806270
W 031 058.868810 005.806390
W 032 058.868750 005.805530
W 033 058.868300 005.805650
W 034 058.868240 005.804800

First column H=hold position L=Land position W=regular waypoint
second column is just a row number
then you have the coordinates.


So the file ends with *END* right?.. i am bit rusty in coding thats why asking silly things

As Dan points out. My example is a set of waypoints (GPS coordinates) that the boat should aim for and is not a program. 
Not knowing your level of programming experience with microcontrollers and your electronics expertise this project might be a bit advanced?

electronics is not an issue for me. the code was the problem that i am confusing


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

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

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)

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!