[Lab] range finding

[Adam Hill]

Hi Darcy,

I've had occasion to think about similar things over the last couple of
years. I wasn't sure what exactly you meant by '20 foot distance'.
Do you mean track them in 3 dimensions inside a 20 ft radius? If so, then
you probably want to go with machine vision (kinect (1st gen) is probably
easier to get up and running but there are some libraries for doing this
with a webcam (not as performant)).

If you mean measure a linear distance from the source to the person, or a
boolean indication of the presence of a person, up to 20ft away, then I
would say something similar to the hardware you're currently using. I would
note that in my experience these are not created equally. I like the MB1210
(
http://www.abra-electronics.com/products/MB1210-Ultrasonic-Range-Finder-%252d-XL%252dMaxSonar%252dEZ1.html).
It was the most reliable out to just less than 20 ft, and is specifically
calibrated for people detection.

Good luck!
-a

On Wednesday, February 5, 2014, Darcy Whyte <darcy at inventorartist.com>
wrote:

> I was just thinking. In the endgame I want to be tracking a person moving
> over a 20 foot distance.
>
> I'm starting to think I might need to try something else. Ideas?
>
>
>
> --
> Darcy Whyte
>
> Art+ inventorArtist.com <http://inventorartist.com/> | Aviation
> rubber-power.com
> Contact: darcy at inventorArtist.com | 613-563-3634 by appointment (no text)
>
>
>
> On Wed, Feb 5, 2014 at 2:02 PM, Darcy Whyte <darcy at inventorartist.com>wrote:
>
>> Hi, I have one of these (I think)
>> http://ramshackblog.blogspot.ca/2012/02/ultrasonic-range-finder-using-sdm-io.html
>>
>> It has four pins.
>>
>> I've got it working using the code at that page. It measures really well
>> up to about 30cm then after that it just prints out 999 cm?
>>
>> I noticed with a piece of paper I can get further (around 70cm).
>>
>> It's supposed to be good for 150cm.
>>
>> Any ideas what's going on here?
>>
>> I have two of them and I tried the other one (in case it was a bu
>> component). But same result...
>>
>>
>> --
>> Darcy Whyte
>>
>> Art+ inventorArtist.com <http://inventorartist.com/> | Aviation
>> rubber-power.com
>> Contact: darcy at inventorArtist.com | 613-563-3634 by appointment (no text)
>>
>>
>
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