SEA RENDERING
@ June 20, 2010
- Actuators / output devices: servo based rudder, 12V 1000 RPM motor
- Control method: autonomous
- CPU: Aruino Duomilanove 328 x 2 and PICAXE
- Operating system: Arduino C++
- Power source: 2 each 12V 12Ah lead batteries
- Programming language: C++
- Sensors / input devices: GPS, digital trancduser
- Target environment: Lakes
| Attachment | Size |
|---|---|
| Bilde.jpg | 881.9 KB |
| MarkII_LOG_microSD.zip | 2.73 KB |
| MarkII_NAV_microSD.zip | 5.11 KB |
| DELFTship_linesplan.pdf | 159.55 KB |
| Mark_II_versjon_1a_mod.zip | 9.02 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
Transducer
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.
@ Sun, 2011-01-23 00:07
Are your happy with your DST800 echo sounder ?
Geir, I'm working on a similar project as yours. In some words I want to survey surf spot reefs to understand better the mechanics that make the waves break (and bottom is very important for the shape of the waves). All this using a robot, of course!
You are using the airmar sounder DST 800. Does it give good result, and in particular is it accurate? For the same price Airmar proposes also P79. In the datasheet P79 is more accurate (less wide beam) but does not send temperature and speed. So the choice is not easy more me.
Do you think, after use, that DST800 is accurate enough to clearly detect and map isolated rocks, for example?
Thanks for your thoughts!
@ Sun, 2011-01-23 11:55
I must admit that I have
I must admit that I have never manually tested the accuracy of the transducer. For our project we don’t need accuracy down to the cm as the goal is to get a contour map off the seafloor and calculate the volume of the lake. I think the target marked for DTS800 is small boats that need information on the keel dept and not for detail mapping. If you need accurate information on large rocks on the seafloor you probably need a side-scanner, but that is in a complete different price range altogether.
When it comes to temperature and speed you could probably just add a temperature probe and the speed is available from GPS information.
@ Sun, 2011-01-23 23:13
Multibeam sounder are very
Multibeam sounder are very expensive as you say, and completly out of my budget, even if of course it would create incredible results in a ridiculous short time!
> "the speed is available from GPS information".
GPS gives ground speed. I thought DST800 was providing surface speed, but after all I don't know, you make me think I was maybe wrong. Anyway, surface speed is important to compute drift. You are working in lakes I think, so you don't care about drift, but I have to care of it since I'll work in the ocean where tide currents can be important.
Did you have some bad surprises to connect DST800 to your arduino? Did you find a way to use the Airmar plug (I think it is a special 5 pins plug), or did you cut the cable and solder directly to your system?
@ Mon, 2011-01-24 22:44
You’re probably right in
You’re probably right in that the transducer gives you surface speed as it has a small impeller that gives you the speed in normal NMEA sentences. And as you say the speed is of no importance to us. It’s fun to know when regarding mission calculations but for the logging part it’s of no value.
When it comes to the cable plug, there is no plug with the system. It’s only bare wires so I cut the cable and added a 3-pin polarized plug of my own. I do believe it’s a regular TTL UART (that make sense as the supplied voltage is 5-24V), -but check the signal before you fire your microcontroller.
The way I did it was to hang the transducer in a bucket of water and checked the signal on a scope. You hear a faint clicking as the transducer fires. If the signal is within the TTL UART range, hook it up and decode the NMEA.
@ Tue, 2010-08-03 09:53
Awesome
This is badass, great job! :D
In reference to the VDIP1 Module.. that's a fun one to play with. lol I had alot of problems myself, had to use someone elses code to be able to use it reliably. I know it's all good and long done by now but for future reference :D
http://openenergymonitor.org/emon/node/44
http://openenergymonitor.org/emon/sites/default/files/SAusbmemory.tar.gz
Bottom link is the .pde files. This is just a "demo" so the data being copied is the "supposed sensors" you should have hooked up. :D Bit late but hey.. better late than never, some how? :)
@ Tue, 2010-08-03 17:48
Thank you for your comments.
Even if the boat is working good now I still want to make it better so I ordered a FEZ Domino from Sparkfun http://www.sparkfun.com/commerce/product_info.php?products_id=9797
I’m accustom to the Microsoft visual studio and the .NET framework so this can be exiting.
Arduino is fine for things not involving string manipulation or file IO, so I'm looking forward to write real managed code in C# and a proper file system.
@ Thu, 2010-07-29 11:59
You have re-inspired me
A few years ago I wanted to set up a robot boat or sub with a camera mounted underneath. I have recently moved into my own apartment in China with a view of the river. Reading about your good work is making me think about re-starting my old project.
Looking at how clear the water is in your photo it would be nice if you could set up a camera under the boat. If those PIR motion detectors work underwater then you might be able to set it up to only take a photo when it detects motion.
@ Tue, 2011-05-31 23:45
Water seals
It might be hard to get them completely sealed. Water would end their usefulness.
What about a clear plexiglas set into the bottom of the boat? That would be easier to seal, and set sensors at enough of an angle that the sensors see through it without reflection ruining your other readings.
@ Tue, 2010-07-27 20:17
this is outragious stuff!,
this is outragious stuff!, im supprised the military aint contacted you for this kind of GPS locomotion :P
Very good build, awsome design im pretty sure you have got allot more insperation where that came from to make the next node even more exciting :D, cant wait to see it :P
@ Wed, 2010-07-21 00:52
Simple and effective design,
Simple and effective design, cool work man... I love it. By the way my ABE its under redisign...
One question- How long last the battery:_?