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Sensor to track moving person? — Parallax Forums

Sensor to track moving person?

ionymousionymous Posts: 29
edited 2010-09-21 16:42 in Accessories
I'm brainstorming a project.
It's a cable cam to follow and film me as I cycle through the woods. The general concept has been implemented by others many times. A carriage with an attached camera rides on pulleys on a cable suspended between two trees. Ideally the camera keeps the subject centered in the video. Sometimes this is implemented with a motor and a remote control, to be controlled be a third party. Sometimes the cable is angled and the carriage moves by gravity.

I would like to implement an autonomous motorized version. This eliminates the need for a third party, and allows uphill movement.

A microcontroller will use some kind of sensors to determine if it needs to speed up or slow down a motor to keep me centered in view. I assume it won't be analyzing video because that would be too costly. Correct me if I'm wrong.

I will be using a GoPro HD camera, which has a very wide angle. It actually looks best only about 4' away. But I'd like the ability to get about 20' away and still track me. I will generally be doing more technical riding and hill climbing. So generally I'll be moving at about 5mph or less, but I may get up to 10mph occasionally.

At first I thought a wiimote IR camera and IR leds could be used. I would wear the IR leds, and the wii camera would track my IR blob. Unfortunately sunlight confuses the wiimote too much.

I then started looking at ultrasonic sensors. I could wear a transmitter that pulses an ultrasonic signal. The carriage could have two ultrasonic receivers mounted on opposite ends, like ears. Based on time of arrival, the microcontroller could determine which way it needs to move.

Any thoughts on this?
Will ultrasonic work?
What would be better?
Visible light would be seen in the video... so that's not preferred.
RF?
Something else?

Thanks for any suggestions.
Ion

Comments

  • vettezr1vettezr1 Posts: 77
    edited 2010-09-15 16:55
    Ion I will be watching this post, I have been trying for a long time to build something like this, a long time ago ,years. circuit cellar had a project that let you build a small system with a parabolic dish that would track a lit match around I could never find it (the article) I want to have a small dish or camera that would track a person as they moved around a room once they came into range,, I tried "PING" " IR" and even the PIR nothing has the resolutuion I want and would get confused after about 8 inches away from the main unit. I know there must be something and hope you find the answear and of course share it with me,,LOL You would think tis would be so easy using a MCU but not for me so far.
  • schillschill Posts: 741
    edited 2010-09-16 06:24
    vettezr1 wrote: »
    ...I have been trying for a long time to build something like this, a long time ago ,years. circuit cellar had a project that let you build a small system with a parabolic dish that would track a lit match around I could never find it (the article)...

    It comes from a Circuit Cellar article in Byte (collected in Ciarcia's Circuit Cellar III):

    http://books.google.com/books?id=zAsN0XCHbFsC&pg=PA42&lpg=PA42&dq=ciarcia+byte+parabolic&source=bl&ots=br9TduIhF6&sig=t4wLtDMCk2Ws9vt7tC15YkLSPRU&hl=en&ei=SRmSTKzDN8WBlAfrkrikCg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBIQ6AEwAA#v=onepage&q&f=false

    I probably have the book around somewhere. I used to have the original issues, but they got accidentally thrown out during a move.
  • ercoerco Posts: 20,256
    edited 2010-09-16 17:22
    You've seen the Skycam page? http://www.skycam.tv/folders.asp?action=display&record=3
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-09-16 20:27
    Erco, you had me worried for a minute. When I read it the first time I thought you mentioned "Skynet" tracking people.....

    Robert
  • ionymousionymous Posts: 29
    edited 2010-09-18 08:07
    Any ideas on sensors to use?
    IR won't work outside.
    Would ultrasonic be worth testing? Wearing an ultrasonic beacon, it will be bouncing around with me. Is that a concern? Vibrations on the trolley?
    With a beacon (instead of echo) can I get more distance?

    Any other ideas?
  • kwinnkwinn Posts: 8,697
    edited 2010-09-19 19:45
    While wearing an ultrasonic beacon and having multiple detectors on the trolley to determine direction and approximate range is possible (after all bats do echolocation), the hardware would be fairly complex. A led beacon and low resolution video camera would simplify the hardware at the cost of more cpu power and possibly more complex software.
  • RobotWorkshopRobotWorkshop Posts: 2,307
    edited 2010-09-21 08:05
    If you want an example of the ultrasonic following just pickup an old Robie Jr robot. There is an ultrasonic remote that you carry and when you use the "Follow Me" mode it will use a pair of ultrasonic detectors on the robot to follow you around. It worked alright.

    Robert
  • vettezr1vettezr1 Posts: 77
    edited 2010-09-21 16:42
    schill that is the one thank you man , That brings me back a few hundred years
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