Instructables

DIY 360 Degree SODAR Device

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Picture of DIY 360 Degree SODAR Device
First off, why did we decide to call this thing SODAR? SOnic Detection and Ranging, or SODAR, is a lot like SONAR and RADAR. However, we don't feel comfortable calling it SONAR because we have no desire to use it for navigation and we aren't under water. Also, it's definitely not RADAR as we are using ultrasonic pulses, not radio waves to find objects. 

With the technicalities out of the way, here are the project's objectives:
 1) To create a freely rotatable SODAR system that can continuously detect objects
 2) To create a UI that displays objects similarly to radar
 3) To make it as portable as possible

To accomplish objective #1, we need a way to prevent wires from tangling while the motor spins. There are two ways that we thought would be relatively easily implementable. The first method would be to use two Arduinos and transceivers for a wireless transmission of data from the spinning platform to the computer for display. The other method would be to use something similar to a rotating electrical connection (REC), where the electrical connection would be maintained using a conductive liquid at the intersection. 

While it seems to go against objective #3, we decided to go with the rotating electrical connection idea. This is mostly because we didn't know if it'd work and wanted to try something new. On top of this, commercial slip rings are upwards of 20 dollars (price found by ellisgl) and we wanted to see how hard it would be to make a reliable REC. In our project, we are using a vinegar-salt solution as an electrical conductive liquid because it is functional and inexpensive.

Future Work Suggestion:

Use wireless transceivers so the project can be placed in one area and send data to the laptop in another area.

Collaborator:

Electrical circuit designer/builder extraordinaire: intensePancake
 
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Jan_Henrik2 months ago

Awesome

well done

this is definitely going to my future DIY projects list.

i will make it and post it when im done and probably going to do both the REC and and try it with wireless communication

burstolava (author)  palestinian-warrior4 months ago

Awesome! Good luck and please post back here when you're up and running...or if you have any questions!

youngdavid9334 months ago

Have you figured out a way to make it wireless yet?

burstolava (author)  youngdavid9334 months ago

We haven't been working on making this project wireless. We saw that as a potential next step for those who were interested and wanted to build upon the project. Two of the possible ways to go about this would be using a bluetooth shield or radio transceivers for the communication between the sensor and the terminal.

tomega34 months ago

Hi, Great instructable. I will try to get it running. The processing code is excellent.

I found a website that shows using a stepper motor and an adafruit slip ring connected via gears. I will try to build it.

see http://curantilrobot.wordpress.com/2013/08/04/rang...

If anyone can help with the cutting out of the mounting frame pieces I would really appreciate the help.


parameshwarnp6 months ago
can i use this sensor in this project ???
http://www.rhydolabz.com/index.php?main_page=product_info&products_id=307
burstolava (author)  parameshwarnp6 months ago
(removed by author or community request)
burstolava (author)  burstolava6 months ago

Sorry, I wanted to edit my post and I couldn't find out how to change it.

burstolava (author)  parameshwarnp6 months ago

The NewPing library doesn't document whether or not it supports that sensor specifically. A major concern with it is that it has a minimum input pulse width of 10 microseconds, while it's only 5 microseconds for our ping sensor. From looking at the NewPing source code, it seems like it'll work for sensors with an input pulse width less than 18 milliseconds, but because it's not specifically mentioned, there is a chance it may not work.


That being said, it's probably worth a shot to try out our code as written. It looks like it'll work, but we can't be completely sure. If you're set on using that sensor and it doesn't work, you could always rewrite that part of the code specifically for your sensor. You'd probably learn something from doing that.

parameshwarnp6 months ago
can i use L293D instead of SN754410 ???
burstolava (author)  parameshwarnp6 months ago
As long as it is a Quadruple Half-H Motor Driver, it will work for this project. However, you should compare the datasheets of the L293D and SN754410 to see if there are any differences in how the connections have to be set up. If there are, the circuit you have to build won't be exactly the one we built, but it should work.
parameshwarnp6 months ago
its showing error in the code:
'NewPing' does not name a type
plz help
burstolava (author)  parameshwarnp6 months ago
This is probably occurring because the compiler can't find the NewPing library. After downloading it, make sure to extract the contents into the general Arduino sketchbook directory. When we installed the Arduino environment, a "libraries" folder was created inside the sketchbook directory. This is where you would want to put the NewPing library.
thanks , it worked . but i'm getting another error :
'class Stepper' hs no member named 'getAngle'
what should i do ??
burstolava (author)  parameshwarnp6 months ago
This is probably happening because the compiler is trying to use the default Stepper library instead of our editted one. We altered the Stepper library to support some basic angle functions that we wanted to use in this project. As stated in Step 7, you should replace the libraries/Stepper directory with the Stepper folder from our repository. This libraries/Stepper directory should be in the Arduino program files (where the executable is for the actual Arduino program). As a side note, we did not alter any of the default functions in the library, so you do not have to worry about our version messing up your other projects that involve the Stepper library. If this does not work, please let me know.
its working , 0 errors . thankyou
amartin5310 months ago
is there a way to extend the range, say to 20 m?
burstolava (author)  amartin5310 months ago
Since the PING sensor's maximum range is 3m, you'd have to either find another ultrasonic distance sensor with that range or buy ultrasonic transducers with that range and build a circuit that uses them. Also, you'd have to change the Arduino code to interface with your new sensor. Finally, you may want to consider slowing down the rotation speed to get more accurate measurements. But yea, 20m is definitely more useful than 3m.
Raphango11 months ago
Great project man! Congratulations!
rluquett1 year ago
nice project! yoi should upload a video shoing it working though
I would love something like this for riding in a velo @ night so I can tell just how far behind me a car is before they even get there.
zomfibame1 year ago
I love the home made REC "slip ring substitution". Too cool.
Absolutely amazing instructable, I was wondering if this could be used on a small LCD screen display rather than a laptop. Would anyone know how to accomplish this?
burstolava (author)  notnowmyheadhurts1 year ago
We aren't that familiar with programming small LCD screens, but if you're planning to use something like a tft screen from arduino, you could use their tft library. You'd have to rewrite the visualization code that we wrote in processing. But the arduino tft library has many similar functions to what we used in processing. One plus is that you wouldn't need to use serial communication like we did. Sounds like a great addition, though. Good luck!
daliad1001 year ago
Nice project, You could try using an audio jack and socket as your connector as you aren't sending much power through it and the sensor kicks out either 5V or 0V so a bit of noise shouldn't matter.
Love it. Thanks for sharing this.
ironmen1 year ago
大哥,我想看中文!
ironmen1 year ago
大哥,我想看中文!
gtr_stitch1 year ago
Why not mount a motor, maybe a stepper, upside down to a stationary platform and have the whole thing rotate? You may need to use batteries, though...but the project looks intensely fascinating!
burstolava (author)  gtr_stitch1 year ago
Nice idea! You just need a way to secure the shaft to some base and make sure the motor can spin that extra weight at the speed you want. We made it to 40 rpm comfortably.
a.steidl1 year ago
Cool project, and well-made ible. Thanks for sharing.
you could have mounted everything on the top and used a serial bluetooth module for the data
burstolava (author)  The nerdling1 year ago
Yeah, that could definitely work, especially if you mount the motor upside down like gtr_stitch said.
ellisgl1 year ago
Why didn't buy a slip ring? Adafruit has them for < $20.
Er... Just read why, so nix the question and keep the statement. =)