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What distance sensors are better and best?

I am working on a much faster & stronger version of Robot Wall Racers, using quite fast RC-cars

I want to use lasers as distance sensors, but I think they will be a little over budget, altough this is a paid for job :)

Yes, SRF05's clai, they can detect a broomstick on 3 meters.. but in reality they are not stable before say 1.5 meters.

1.5 meters when you are traveling at 25km/h is NOT a lot, when you even are set up with drifting tyres.

So I would like a little longer "view". And it can be pricey, say USD 50-70 for each sensor.

only problem;

I do not know of any better sensors than SRF05 at this level, do you? 

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I have had some success with a homebrew range finder that costs about $10(US) to produce.

It uses a cheap red laser pointer, photodarlington, filter, and spinning mirror. I usually include a dedicated PIC micro to turn the timing into serial range data for a master micro.

Range is good from 3" out to 50' depending on conditions. And accuaracy is traded for refresh rate depending on how fast the mirror spins - since it uses the triangulation method. Range resolution of <1cm updated @40KHz is what I often use. 

The problem I can see using this for your application is that a car could crash into a chair leg because the laser range finder might be pointed to one side or the other. In this case the more coarse resolution of sonar sensors may be a benefit - I have had good results from MAXbotics EZ1.



MechGeek2000's picture

Actually, all they do is light up some LEDS that you can see in the rearview mirror. They aren't attached to any type of control device.  

Have you tried the higher end sharp sensors? Some go out several meters. Have you thought of using more than one sensor?



Rudolph's picture

Maxbotix claims 6.45 meters on their sonar parts. I've never used one, and I don't have one to verify.

Maybe an automobile junkyard could have fun stuff. More and more late model cars are having distance sensors embedded in the bumpers. I guess the idea is so the car can brake for you when you're about to hit something. Then again, maybe pirating distance sensors out of a crashed car is proof that the sensors didn't work very well...

fritsl's picture

Thanks for the Maxbotix-tip! Was just using them, but another series. Will investigate!

Regarding the IRL-cars and their sensors; I think they are for assisting while parking :) And I also think that the logic is hidden and would take days to hack & use.. But nice thinking though, thanks!

TeleFox's picture

I'm not totally sure about the parking sensors that are built into new cars, but the upgrade kits you can buy are typically wide-angle ultrasonic sensors, for generic proximity detection. If you put a pair of those on a comparatively tiny RC car you'd end up detecting objects that were off to the sides and your bot would probably spend a lot of time avoiding objects it wasn't actually going to hit.
Unfotunately I can't offer any advice in the way of alternatives - all my experience is either with homebuilt IR/LASER/capacitive sensors or with high-cost industrial sensors =/