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Topic: Ultrasonic Send/Receive (Read 96 times) previous topic - next topic

willduino

Hello,

I am a 4th year Mechanical Eng. student and I am just about to embark on my final year project. I am to design an automatic glass cleaner for fish tanks. I think there are a few ways this can be done but there is one currently on the market called MOAI that utilises ultrasound.

It works by having a dock in the top left corner, and the cleaning unit goes and cleans the tank using ultrasound to navigate. You program the dimension of the tank using an app.

I have just ordered my Due and have never used an Arduino so my knowledge is limited to the few bits of electronics that actually stuck from the last 3 years! I also do not have an amazing knowledge of ultrasound devices so my questions are;

  • will there be an ultrasound sender on the dock and a receiver on the cleaner unit? Or the other way round?
  • and are there components like this for the Arduino that would work for my project?


Here's a link to their website for a bit of context; https://www.moaidevices.com

I am super excited to get working with my Arduino, one of my courses this year is based almost entirely on the Arduino board so I am getting quite a crash course!

Thanks for your help in advance!

pylon

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will there be an ultrasound sender on the dock and a receiver on the cleaner unit? Or the other way round?
I'd say both. To be able to navigate using ultrasound the mobile cleaner must answer, there must be a round trip, otherwise you don't have the distance but only the angle to the base station.

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I think there are a few ways this can be done but there is one currently on the market called MOAI that utilises ultrasound.
That means your final year project choose out of several possible way exactly the same way as a product already on the market? Why don't you try a different way? Just copying a device commercially available isn't innovative. Is it this what you learned in college?

willduino

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I'd say both. To be able to navigate using ultrasound the mobile cleaner must answer, there must be a round trip, otherwise you don't have the distance but only the angle to the base station.
Ah okay thanks, so both halves would essentially have the same components?

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That means your final year project choose out of several possible way exactly the same way as a product already on the market? Why don't you try a different way? Just copying a device commercially available isn't innovative. Is it this what you learned in college?
Yeah I know it's not innovative I'm just investigating the options I currently have. I haven't been given my official guidelines for the project yet so I am just trying to figure out my possibilities. Even if I used ultrasound I could use it in a different way - I did say there were a few ways but so far ultrasound has come up as the most sensible and accurate solution!

wvmarle

Why not bring it to the next level.
1) no need to disturb your fish with ultrasound (there just have to be species that can hear that).
2) no need to program anything, chunk it in the tank and that's it (well, place it in the tank against the glass while attached to the base station - in a corner so it can be used as reference to find the base station).

Then have your cleaner robot travel around the tank on it's own, measuring the dimensions as it goes, sensing where the gravel layer on the bottom is, sensing where things are attached to the glass that have to be circumnavigated. You may require it to be a rectangular tank, as curved surfaces make it a lot harder. Create a map and it plots a good course to cover all the glass, and when in need of some power return to the base station to top up (hence the corner: makes navigating easier, just remember the path to the corner navigating references such as other corners, the water level and the bottom level).

Sounds simple enough but probably not going to be easy :-)
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

willduino

Why not bring it to the next level.
1) no need to disturb your fish with ultrasound (there just have to be species that can hear that).
2) no need to program anything, chunk it in the tank and that's it (well, place it in the tank against the glass while attached to the base station - in a corner so it can be used as reference to find the base station).

Then have your cleaner robot travel around the tank on it's own, measuring the dimensions as it goes, sensing where the gravel layer on the bottom is, sensing where things are attached to the glass that have to be circumnavigated. You may require it to be a rectangular tank, as curved surfaces make it a lot harder. Create a map and it plots a good course to cover all the glass, and when in need of some power return to the base station to top up (hence the corner: makes navigating easier, just remember the path to the corner navigating references such as other corners, the water level and the bottom level).

Sounds simple enough but probably not going to be easy :-)
Thanks for the suggestion, with this I would be worried about a wheel slipping or not turning as it should as that would then make it go off course if it doesn't have the constant back and forth response with the ultrasound dock as a reference. Unless I misunderstood you? I also got to see the tank I would be dealing with yesterday and it turns out it has a slightly curved front + curved corners. The projects new focus is to design something to go (and clean) round the corners!

wvmarle

Part of my idea is that you do not keep in contact with the base station.
Curved corners, if tight enough, should be quite easy to detect as the rover travels along the glass (how is it supposed to stick to the glass, and handle corners?), as it is very different than the normal slightly curved or even straight glass.
Even with a little slip you can reasonably well keep track of where you are by measuring distance. The angle with the vertical you can find using an accelerometer, as it shows you which way gravity points, and that is down. So you know whether you're pointing up or down, and left or right.
You basically have a map that consists of four rectangles: the glass sheets between two corners, the surface of the water and the bottom of the tank. In one of those corners is your base station. Of course the far edge of rectangle 4 connects to the far edge of rectangle 1.
There may be some obstacles - those the rover can map as well, as keep-out areas on the map.
Your rover has to clean the whole tank, so basically it would start at its base station, goes to the water surface, and starts cleaning. Every time it reaches an edge it turns around and continues a little lower, until the bottom is reached. Then it goes around the corner, and continues with that sheet.
Of course you don't know exactly where in the rectangle you are, you just continue going straight (neutral buoyancy goes a long way to not slipping up or down) using your accelerometer for reference until you reach the next edge. You know on which wall of the aquarium you are, and use that knowledge plus the edges as reference to get back to the base station, which is at the top of a corner (could be out of the water even).
Corners can be done by having wheels on all four sides of the robot. So when a corner is reached, another surface of the robot touches the new side of the aquarium. Rounded corners and non-90° angles do make this a bit harder of course.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

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