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SV: [basicstamps] Lawn-Mover with BS2! Project page — Parallax Forums

SV: [basicstamps] Lawn-Mover with BS2! Project page

ArchiverArchiver Posts: 46,084
edited 2000-08-08 16:11 in General Discussion
Hi Kerry

Many thanx for your tips...have read about radio-fences before, but never hear
of real-life experience of them...

Sounds like the perfect solution for me BUT! Since i'm kind of a nerd, and also
has a large number of peaople following my RoboCut project AND a really would
like to know HOW such a fence works...

I hold a masters degree in electronics and Computer science so i think i should
be able to build a simple circuitry on my own, but of great help would be a good
starting point regarding the frequency, voltage etc on the commonly used Radio
fences.

Is the cable an ordinary cable, is there an coil OR some sort of antenna in the
dog-collar, What is the Voltage and frequency of the signal in the buried cable
etc...


Now your questions about my project!

Regarding the IR-navigation, there is another project on my site describing an
IR-navigtion/self-charging system for a small bot, the GROWBOT have a look at

http://www.lls.se/~mux/micro/take_home.html

However, the arrangement with the lens will not be used on the lawnmover.
Instead, the mover will rotate in small steps while looking for the IR signal,
when signal is detected it will continu to rotate until the signal is lost...Now
the mover knows the "detecting angle" and rotate half the angle in reverse
direction which ends up with surprisingly precision! Pretty smart or...

The IR-navigation for the mover is right now under development.

Obstacle avoidance with two IROD-modules works well, overall, my feeling is that
this is an easier task outdoors than indoors...and one more thing, i always
program my bots with some form of random/unexpected manouvers...this seems to be
the best way to get out of trouble...suddenly backing in Zick Zack patterns or
similar, and make sure you use a random trigger!



Ursprungligt meddelande
Fr

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2000-08-08 16:11
    hello Hans: Thank you for your response. I do not know to much about how the
    radio fence works. It is just a plain ordinary shielded wire buried in the
    ground. I used some old junk wire laying around for 1 section and it worked
    fine. the manual says around 22-16 gauge wire. radiofence.com
    They say on the site they use a 10.65KHz signal.
    I know the system needs a ground wire attached to a rod in the physical
    earth(ground)
    I dont know what the internals of the transmitter or receiver are. the
    transmitter uses a 9 volt power supply,but I suppose the output could be
    anything. I doubt it is high AC voltage or they would have started with an
    AC voltage I presume?
    There is also a wireless dog collar as well that uses a radio signal to
    activate the dog collar when the dog gets out of range.
    I dont blame you, it is much more fun and rewarding to build the system
    yourself.
    I have always heard of a buried wire that would squeal in a base station
    when a person walks near the wire. Supposedly was used in the early days of
    Tube style radio (or in your neck of the woods Valves), as a security
    alarm.I never found any more info however. I am guessing this dog fence
    works on a similar principle but with modern electronics.
    Possibly someone else on the list has more information

    Sincerely
    Kerry
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