safety guard for blind (highly important)

[khangzing]

i was doing the project which consist of ir sensor,pic controller and buzzer,but i also interested to know that,is that infrared sensor can detect metallic and nonmetallic object?(pond,drain etc) if not,which kind of sensor should i use which consist of at least 2-3m sensing range? i also wanted to know how they connect each other? anyone having the circuit diagram? please help me thanks...

if i didn't use buzzer,my idea was when obstacle is detected,a voice will play through ear phone/speaker to user which tell the user obstacle is detect. How to make the system recognize the incoming object?

 

[BradtheRad]

What you are describing is on the order of artificial intelligence.

It has turned out to be a huge chore to program a computer to recognize everyday objects, yet a toddler can do it easily.

You will need something like a camera to give a detailed picture, and a software algorithm which can detect shapes, colors, etc.
It will be even more effort to get it to discern flat objects, reflective objects, background vs foreground, metallic vs. non-metallic, etc.

 

[khangzing]

ok,how about when the object is detected,i want the device to count the distance and tell the user through headphone,how can i do that?can u give me the circuit diagram or references?or block diagram,circuit diagram etc....?

 

[BradtheRad]

There are a few strategies to do range-finding:
* audio (ultrasonic) echo reflection
* two viewfinders converging and triangulating
* IR pulsee reflection.

I don't know which type would be most feasible. I have not seen automatic range-finder projects which are suitable for the non-professional to make, and which would be sufficiently accurate to aid the blind.

To measure 2 or 3 meters, you might consider the last option. My camera determines distance by sending out a brief IR pulse. If it returns in a hundred millionth of a second round trip, then it sets its focal length for 5 feet.

To make a circuit operate that fast, will require careful design and construction. The IR beam will require power, which requires large battery capacity (since you want portability).

The audio reflection method operates on a slower speed, so it might be easier to construct. However it may not act right if there are many reflective surfaces sending back echoes.

 

[khangzing]

can you provide me the circuit diagram(you said careful design and construction) and how the IR reflect pulse works?and u said required large battery capacity,approximate how much it need?do you have e-mail or contact?

 

[BradtheRad]

I have not built this type of project, so I'm afraid I cannot be of much help.

Here are a few links.

http://slab.concordia.ca/2009/arduino/ir-range-finder/





http://www.societyofrobots.com/sensors_sharpirrange.shtml

http://www.electro-tech-online.com/...3169-hellp-me-build-laser-range-finder-2.html

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An acoustic echo range finder is not likely to have fine resolution. It might be useful to alert that a wall is a few feet away, or that steps are directly ahead, etc.

http://www.timnolan.com/index.php?page=ultrasonic-rangefinder-project

http://www.best-microcontroller-projects.com/pic-sonar.html

http://tutorial.cytron.com.my/2011/08/12/project-7-ultrasonic-range-finder-to-lcd-display/

 

[khangzing]

ok,ignore the range finder,lets say when obstacle is detected,a predefine voice will play back and notify the user obstacle are nearby, i using pic16f877a,ir mid range proximity sensor, apr 9301 voice chip, how to build the circuit?

 

[BradtheRad]

ok,ignore the range finder,lets say when obstacle is detected,a predefine voice will play back and notify the user obstacle are nearby, i using pic16f877a,ir mid range proximity sensor, apr 9301 voice chip, how to build the circuit?

Sorry, I have no experience with pics or microcontrollers.

Notice that if you make a proximity sensor which is sensitive enough to detect nearby obstacles, it is also liable to detect the person it is attached to.

There is still the idea of camera-based recognition of movement. That is a big challenge too. Researchers have worked for years to make computer programs that accept images streaming live from a camera, and examine them pixel by pixel, and detect shapes, movement, etc. If you are lucky you may meet up with someone in this field who is knowledgeable and generous.

Perhaps an expert here will reply and give you more information.
Or it might pay to look for websites that describe a project to do what you are asking.

 

[khangzing]

ok,for build a circuit,what are the things i need to pay more attention?or any website for reference?thanks bro for giving so much information =)

 

[BradtheRad]

Ah, well...
I think I know where you can find more information!
Google is your friend.

This is the sort of project that robot-builders might take on. Then if you find one website, sometimes it is in a web-ring with related websites.