Underwater Robot - Sensors

[Ric0]

Hello everyone... I'm new here.

I'm Rico from Singapore, me and my project team has been tasked by my school to build the first ever Autonomous Underwater robot for our school. Because we are the pioneers not much help has been given too us.

Right now we are stuck trying to figure out which sensors to use for our robot I hope you guys can help point me in the right direction.

Firstly I need to differentiate the side of the tanks, the glass tank and black tape marker

Below is the complete rule book of the competition that we have signed up for

http://guppy.mpe.nus.edu.sg/srg/urc.pdf

[TrickyNekro]

Anything that depends on light should work...
But I bet you need a clear crystal glass housing to do this...
Also sonar might be and idea...
I think there are water proof transducers that you can find!!!

Cheers on your project mates, and welcome here at this community (rather than just another forum....)

Best Regards,
Lefteris
Greece

[SmAsH]

wow, that comp looks like fun! i would agree with tricky that sonar is a good bet for underwater use, is your robot going to crawl along the bottom or swim with some kind of "rudder" or "fin"? to pick up the objects  themselves you could either use a gripper or an electromagnet on an arm. not really sure of much else as ive never done anything like this. hope this helped a bit

[superchiku]

man floatation...have a look at admin's waterproofing tutorial..it will help u a lot...u wan waterproff literally anything..get a glue gun to seal in ur chassis...sensors ..i guess ultrasonic sensors would be a gr8 asset here..

[Ric0]

hey guys ... thanx for the advice ... will read up on the things you guys provided...

wow, that comp looks like fun! i would agree with tricky that sonar is a good bet for underwater use, is your robot going to crawl along the bottom or swim with some kind of "rudder" or "fin"? to pick up the objects  themselves you could either use a gripper or an electromagnet on an arm. not really sure of much else as ive never done anything like this. hope this helped a bit

hmmm was planning for it to dive(using a piston tank) to the middle then set off to the area where the metal nuts are.. think I need to solve the problem for sensing the black tape marking in the middle...

Right now  I have this sonar sensor in my lab... im still learning how to use it...
do u guys can work?

http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/Level/a/ProductID/92/Default.aspx?SortField=ProductName%2cProductName

[TrickyNekro]

Unfortunately no......
I'm sorry.... You need special underwater ultrasonic transducers something like this:

http://www.futurlec.com/Ultrasonic_Sensors.shtml
If I remember right they are 100% waterproof...
Although I can not quarantine for their functionality underwater

[airman00]

can you take off the Parallx Ping's ultrasonic transceivers and just replace it with underwater ones?
Obviously the two have different internal resistances and different properties which might change some things, but would it sort of work?

[TrickyNekro]

To tell you the truth.... I don't know....
Suppose the work at the same frequency yes you can....
But hey.... Making your own sonar isn't so hard......
If I'm right I unearthed some schematics from the University's lab......
Guess that university is really becoming my second home after all....

[Ric0]

To tell you the truth.... I don't know....
Suppose the work at the same frequency yes you can....
But hey.... Making your own sonar isn't so hard......
If I'm right I unearthed some schematics from the University's lab......
Guess that university is really becoming my second home after all....

haha can u share with me how to make the sonar ?

[Ric0]

can you take off the Parallx Ping's ultrasonic transceivers and just replace it with underwater ones?
Obviously the two have different internal resistances and different properties which might change some things, but would it sort of work?

hmm if i do that .. and use measuring tape to redetermine the distance to freq ratio will that work ? haha juz a thought

[TrickyNekro]

To tell you the truth.... I don't know....
Suppose the work at the same frequency yes you can....
But hey.... Making your own sonar isn't so hard......
If I'm right I unearthed some schematics from the University's lab......
Guess that university is really becoming my second home after all....

haha can u share with me how to make the sonar ?

I just show some circuitry on proto boards.....
Basically, it's all about software... I think the only thing I saw electronic, apart from the controller was
either an amplifier (op amp) either a comparator....
I'll check out next week.... We still have holidays here...