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Author Topic: Most Efficient Multidirectional Sonar Method  (Read 671 times)

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Offline BigKLaxerTopic starter

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Most Efficient Multidirectional Sonar Method
« on: June 23, 2011, 09:04:04 AM »
So I'm currently in the process of designing a multidirectional sonar system for my Power Wheels Modded Robot (http://www.udrobot.blogspot.com/) and I'm as of right now unsure of the most efficient sonar design that will give me the most accurate information with good enough resolution.  I'm building the ultrasonic sensors myself and have 10 transducers so I can get anywhere from 5-10 modules out of them, so cost isn't really an issue.

So my two design ideas would be to
1. Mount an ultrasonic sensor on the front, back, and both sides of the robot, and have them share a 555 signal generator with one Atmega for the controller and timer for all of them or,
2. Have a singular module mounted to the top of the robot on a 360 degree servo with perhaps an ATtiny as both the signal generator and timer.

Option 1 would be a bit more difficult to implement and would involve more wires running everywhere and might involve more power consumption, but would result in faster feedback from the 4 important directions.

Option 2 would be a lot easier to implement, would be more contained and more energy efficient when being used lightly, and would provide a higher resolution for the area mapping I'd like to one day implement, but the servo would take a lot more energy (I think?) when highly active (When approaching a wall or travelling down a narrow hallway), it would take longer to get feedback if, for example, left and right both need to be tracked so the robot doesn't run into the sides of a hallway, and so the sonar would constantly have to pan back and forth.  I'm also worried that having the servo at the top of the robot would cause it to miss some lower targets (but perhaps this could be fixed with a pan/tilt servo bracket?) and that the extra degrees of resolution will be essentially useless due to reflections of the sonar off of targets that are not perpendicular to the sonar beam.

I was wondering if anyone who as worked with sonar and servos could possibly give me some advice on this decision and help me figure out which option would be better to implement, both immediately or in the long run.  Thanks a bunch!
Experimental Mobile Robotics Platform: http://www.udrobot.blogspot.com

Offline Soeren

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Re: Most Efficient Multidirectional Sonar Method
« Reply #1 on: June 23, 2011, 12:27:06 PM »
Hi,

So my two design ideas would be to
1. Mount an ultrasonic sensor on the front, back, and both sides of the robot, and have them share a 555 signal generator with one Atmega for the controller and timer for all of them or,
2. Have a singular module mounted to the top of the robot on a 360 degree servo with perhaps an ATtiny as both the signal generator and timer.
You could combine the ideas.
If you mount 4 (or more) transducers on a rotatable disk with all the electronics it needs, you would cut scan time with the same amount.
Don't fire more than one US at a time though, or you would likely get lots of interfering signals.

No need for a 555 if you're using a controller anyway.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline BigKLaxerTopic starter

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Re: Most Efficient Multidirectional Sonar Method
« Reply #2 on: June 24, 2011, 09:05:06 AM »
Good point.  I'll probably end up doing that with 2 ultrasonic sensors facing in opposite directions.  That way I essentially have the best of both worlds.  Then I could just add a few bump or IR sensors to detect the smaller objects that the US is too high to reach.  Thanks!
Experimental Mobile Robotics Platform: http://www.udrobot.blogspot.com

 


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