Hey , if anybody here has made a obstacle avoiding quad .
.... If yes please give some advice if its better to use infra red or sonar , and what is d best arduino 2use with it , can I use d arduino uno ?

Better use sonar to avoid interferance with sunlight, you may have to install atleast 4 of them (on 4 sides).

So you need more IO pins , so go for Arduino mega. Or if you also want more processing  power, get any powerful arduino boards.

You can also try using camera and raspberry pi

Go for mega
And keep us updated on the progress
Best of luck

http://www.digibay.in/465-arduino-uno-r3-atmega328-made-in-italy, can I use this??

Arduino wont be enough because you also need pin for the 3 axis gyro with the motors for the quad, a mega is expensive but pays off later

it will not work ...
you are equating a ground robot with a quad ... a quad will not be able to
react fast enough ( it will not have ground traction ) to have any meaningful
obstacle avoidance .
It would require quite a lot processing power as you would require a PID loop for
stability in addition to obstacle avoidance.  if however you do manage to make one
pls post details as I would be interested in copying your design.

go for pixhawk

That's why I recommend ultrasonic distance sensors, big solid obstacles can be sensed from distance of few meters so there can be provision in program to alter the course of flight.

But you need more processing power and more IO ports.

@roshan.dixit  , Pixhawk is based on atmega 2560 (arduino mega) . It doesn't have obstacle avoidance.

i agree with saikat , but if he needs to make a autonomous quad which maneuvers in say a office area then i could work .
As for faster reaction time you should build a smaller quad , a 250 quad would be good
and immanuel you would have to write codes for 2 modes ,one should be the basic that you can even find online ,and an autonomous one that would scan for objects in both axis and move very slowly like with a speed of 0.3m/s ,and stop before a distance of min. 1 m.
and i must tell you it will take a long time .
can you tell me how much experience you have with arduino IDE , and have ever used the ultrasonic sensor before with a project or something like it?

ultrasonic sensors are usually used to sense distance, the same can be implemented here as proximity sensor, how ever sensitivity is low,
This sensors, can find hard objects in a range of tens of meters, so there is more time for a reaction loop to be performed (which can be just stopping in mid air, or take alternative courses as per the instruction ). 

Remember, If there is a will there is a way.

i got it what you said sooraj 
but a quad moves forward at minimum pitch at a speed of 1-3 m/s and at high speed it will be very difficult to control it , but a great code can maybe make it work.and there will be another problem there woud be just 4 sensors , so as the quad moves diagonally other objects would be a problem.(see the photo attached)
so a better solution would be going  at low speed and only moving linearly (photo attached) .
its a great project , but somewhat difficult.
best of luck immanuel

That's a lot work in paint, rohan .

Yes you are right.
the placing of these sensors and also the no. of sensors, plays a key role.
But if this is intended to work outside, GPS will do for most obstacle avoiding (not for avoiding small creatures and things though)  .
The other way is using raspberry pi with camera for image manipulation and interpretation.

i am also working to make obstacle avoidance(now only working collition detection) in my quad(multiwii mods and arduino mega) and ultrasonic sensors working better than infra(cant be used in heavy light situation, low accuracy, and cant detect black things),  but the ultrasonic sensors also failed in too many situations like small objects, rough concrete walls,

then used cameras, but cant detect distance using single cam, at least 2 cams needed for distance calculation in one direction, so this will increase weight, too complicated image processing and calculation will take time and quad will collide before detection if moving fast.

have the projects codes in progress if any one want to join just message me.

so now going to try microsoft kinect (maybe a backend server need to process) and ordered one.

I was planning 2 use 5 sonars , (one under d quad), maybe and arduino mega 2 process the analog , and then send it 2 an apm 2 board , I do really need some help in programming though, can anyone help ??( the basic stuff I can take from online , but for tunning it and stuff i need help ...)

http://www.flitetest.com/articles/quadcopter-obstacle-avoidance-system-using-arduino. ,something like this

Each sonar covers max of around 25 degree, so if you planing to use 5 sonars in each direction( front, back, left, right,) that must have blind spots.
Batter way to use at least 3 in front side and always move forward direction.

Any update on this project?

Quote from: sooraj.palakkad on November 06, 2014, 09:26:43 PM
Better use sonar to avoid interferance with sunlight, you may have to install atleast 4 of them (on 4 sides).

So you need more IO pins , so go for Arduino mega. Or if you also want more processing  power, get any powerful arduino boards.

You can also try using camera and raspberry pi

i would suggest using a single 3d cam and using mirrors for rear and side view.

Quote from: Tanmay.mathur on March 06, 2015, 05:47:19 PM

Quote from: sooraj.palakkad on November 06, 2014, 09:26:43 PM
Better use sonar to avoid interferance with sunlight, you may have to install atleast 4 of them (on 4 sides).

So you need more IO pins , so go for Arduino mega. Or if you also want more processing  power, get any powerful arduino boards.

You can also try using camera and raspberry pi

i would suggest using a single 3d cam and using mirrors for rear and side view.

Hey Tanmay, I would like to know more on using 3D cam concept of yours. Can you please elaborate your idea a little more

Don't go for 3d cam as it would require more processing speed a dedicated computer which will increase complexity go for sonars but the quads wouldn't be as agile as  a obstacle avoiding robot 

There is a faculty in IIT Kanpur working on something similar (although not a quad). I remember them using a Microsoft Kinect Sensor and NAVSTIK (http://navstik.org/home/).

Here is a link to the research page http://www.iitk.ac.in/aero/abhishek/?research,3

Scroll down to the relevant section!
EDIT: Looks like the webpage hasn't been updated. Initially I believe they started by using Arduino Uno and from what I remember seeing last year, they had moved over to NAVSTIK, I could be wrong though. You might want to email Dr. Abhishek, he is a wonderful person and I'm sure he will help you.

Having only 4 sensors will not be sufficient if you are placing them in each corner. Actually, not even 8 will suffice.
I would suggest to mount a very good sensor at top of the servo which will rotate continuously. That way you can not only save on sensors, but can also work with arduino uno to save on cost. I did such thing in my rover and it works well. This approach works only for slow quads though.

By the way, you can use cheap uno clone if you are in experiment phase. It will save you in event of crash

3d cam can measure the depth and by using the mirrors your quad will be able to see whats in the sides and in the rear section . Hence one cam does all visual work . Use laser pointers to determine the relative  3 dimensional position of the quad in the surrounding .

Quote from: rahimv on March 06, 2015, 10:08:13 PM
Having only 4 sensors will not be sufficient if you are placing them in each corner. Actually, not even 8 will suffice.
I would suggest to mount a very good sensor at top of the servo which will rotate continuously. That way you can not only save on sensors, but can also work with arduino uno to save on cost. I did such thing in my rover and it works well. This approach works only for slow quads though.

By the way, you can use cheap uno clone if you are in experiment phase. It will save you in event of crash

@rahimv what in case of a mechanical failure of the servo? the quad would become blind! Can you tell me how even 8 won't suffice? Six sonar sensors are sufficient for navigation! 8 for more precise navigation!
And you can get 10 sonar sensors at the cost of a good servo so how does a "good" servo sensor combination save money?

Link for Sensor: http://www.ebay.com/itm/10-x-Ultrasonic-Module-HC-SR04-Distance-Measuring-Transducer-Sensor-for-Arduino-/130705106799?pt=LH_DefaultDomain_0&hash=item1e6ea1a76f

Incase of using 6 or more sonars even if one sonar gets damaged the quad can still navigate!