Arduino Forum

Topics => Robotics => Topic started by: srowshan on Jun 05, 2014, 05:05 pm

Title: Using invisible dog fence as boundary for lawn mower robot
Post by: srowshan on Jun 05, 2014, 05:05 pm
Hi all, I've been working on a lawn mower robot. I have it running and mowing fine. But I need to somehow set a boundary for it. Given that I already have a Dogwatch wire fence for my dog, I'm trying to leverage it. I've seen multiple topics on this forum discussing this topic, but couldn't find what I am looking for. According to the documentation my Dogwatch transmitter sends a an FM 8 KHZ signal. It can be also set to send the signal in FM, or at 4 KHZ AM or FM.

I've been looking for a pre-built Arduino compatible AM or FM receiver that can pick up this signal. I've had no luck finding one, and I'm not familiar with radio circuits or very low frequency receivers. And I ideally need something prebuilt. Any help is appreciated.

Regards,
Mak
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: CrossRoads on Jun 05, 2014, 07:41 pm
That's pretty low frequency. Can you get a replacement collar and use that as the sensor, use the 'tickle" output and turn before you reach the 'full shock' distance?
Or, turn at the 2nd one I guess, depending on how close it is to sidewalks & stuff.
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: BulldogLowell on Jun 05, 2014, 07:45 pm

That's pretty low frequency. Can you get a replacement collar and use that as the sensor, use the 'tickle" output and turn before you reach the 'full shock' distance?
Or, turn at the 2nd one I guess, depending on how close it is to sidewalks & stuff.


Don't make your lawnmower too intelligent.  My dog figured out that it can run the batteries down by standing close to the boundary.  When the sound/vibration warnings stop, the darn dog walks across the fence.
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: CrossRoads on Jun 05, 2014, 07:50 pm
Mine would do similar - sneak forward, and if no shock he'd roam for the day - and then come home before we did so we wouldn't know he'd been gone unless someone ratted him out!
Title: Lawn mower robot and dog wire fence
Post by: srowshan on Jun 06, 2014, 01:36 am
Hi all, I've been working on a lawn mower robot. I have it running and mowing fine. But I need to somehow set a boundary for it. Given that I already have a Dogwatch wire fence for my dog, I'm trying to leverage it. I've seen multiple topics on this forum discussing this topic, but couldn't find what I am looking for. According to the documentation my Dogwatch transmitter sends an 8 KHZ FM signal through the wire fence. It can be also set to send an AM signal 4 KHZ or 8 KHZ.

I've been looking for a prebuilt Arduino compatible AM or FM receiver that can pick up this low frequency signal. I've had no luck finding one, and I'm not familiar with radio circuits or how to detect very low frequencies. And I ideally I need something prebuilt. Any help is appreciated.

Regards,
Mak
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: srowshan on Jun 06, 2014, 01:42 am

That's pretty low frequency. Can you get a replacement collar and use that as the sensor, use the 'tickle" output and turn before you reach the 'full shock' distance?
Or, turn at the 2nd one I guess, depending on how close it is to sidewalks & stuff.


Unfortunately the replacement collars are very expensive (over $150.) So I was hoping for a less expensive solution.
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: srowshan on Jun 06, 2014, 01:45 am


That's pretty low frequency. Can you get a replacement collar and use that as the sensor, use the 'tickle" output and turn before you reach the 'full shock' distance?
Or, turn at the 2nd one I guess, depending on how close it is to sidewalks & stuff.


Don't make your lawnmower too intelligent.  My dog figured out that it can run the batteries down by standing close to the boundary.  When the sound/vibration warnings stop, the darn dog walks across the fence.


Fortunately my dog is not that smart! The fence is working fine for her!
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: BulldogLowell on Jun 06, 2014, 01:47 am
there are lots of posts on this subject...

Here's one (http://forum.arduino.cc/index.php?topic=118885.msg894803#msg894803)

Title: Re: Lawn mower robot and dog wire fence
Post by: rogerClark on Jun 06, 2014, 01:47 am
Can you send us a link to the DogWatch system ?

You said that the fence sends out 4khz, which implies that there is some sort of receiver

Does the dog wear a collar which detects the 4hkz and bleeps etc on the dog when it gets close to the fence

Or does the dog wear something that causes the fence controller to know that the dog is near the fence

Or does the system not need any other hardware, ie is it sensing body mass etc possibly by capacitive coupling ??


If its a system where the dog wears a detector, the simplest solution is to buy another dog collar detector and take it apart and connect the arduino to where the LED or buzzer etc was connected

However I suspect its more complicated than this ;-(
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: srowshan on Jun 06, 2014, 01:51 am

there are lots of posts on this subject...

Here's one (http://forum.arduino.cc/index.php?topic=118885.msg894803#msg894803)




Yes, I've seen this one and some others. Most use a replacement collar/receiver. In my case that is very expensive. So I'm looking for an alternative solution.
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: CrossRoads on Jun 06, 2014, 03:06 am
$150? Wow. I bought a whole system for less that.
http://www.homedepot.com/p/PetSafe-Innotek-Wired-1-3-Acre-In-Ground-Dog-Fence-SD-2000/100660387
Scroll down - extra collar $50

http://www.homedepot.com/p/PetSafe-10-Acre-In-Ground-Pet-Containment-System-RF-3004W-11/100382345
http://www.homedepot.com/p/PetSafe-1-2-sq-ft-Wireless-Receiver-and-Collar-IF-275/100349982
Title: Re: Lawn mower robot and dog wire fence
Post by: lar3ry on Jun 06, 2014, 06:11 am
http://forum.arduino.cc/index.php?action=post;topic=245228.0;num_replies=1 (http://forum.arduino.cc/index.php?action=post;topic=245228.0;num_replies=1)
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: CrossRoads on Jun 06, 2014, 03:19 pm
Please Don't CrossPost. If you don't like the subforum the topic is in we can move it.
One topic, one conversation.
Thanks
Moderator
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: keeper63 on Jun 07, 2014, 07:50 pm
Have you tried using the receiver portion of a cheap "wire-tracer" tool - example:

http://www.harborfreight.com/cable-tracker-94181.html

Such a device might be able to pick up the signal that your virtual fence transmitter is outputting, and you could then use the presence of that signal (and/or the strength) to determine where your robot is in relation to the boundary wire.

Might be worth purchasing and trying it out - worst case is that you are left with a wireless signal tracing tool (which are pretty useful on their own for tracking problems with wiring you can't see easily).
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: Jantje on Jun 07, 2014, 10:08 pm

Have you tried using the receiver portion of a cheap "wire-tracer" tool - example:

Good thinking
May be a add-on for my mowrobot later.
Best regards
Jantje
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: keeper63 on Jun 08, 2014, 07:46 pm

Good thinking
May be a add-on for my mowrobot later.


I've been thinking about this (border/non-grass detection) for a while, ever since acquiring a Friendly Robotics RL-500 mower for $50.00 USD off a local guy on craigslist; I swear that one day I am going to get it running again...

My thing is that I am a very lazy person - and I don't want to dig and bury a powered "border fence" - so I have been contemplating a ton of alternatives.

One involves magnets and hall-effect sensors. Basically I would mold small rare-earth magnets into plastic golf-ball tees, and spike them along the edges and other no-go areas. Mount hall-effect sensors on the mower platform, and let it detect them. Passive, cheap, easy to replace.

Another option was to detect the presence of grass in some manner. I've thought about the idea of a humidity sensor, maybe coupled with a color sensor (or something) - to detect mowed vs. unmowed (vs non-grass) areas. Such could also improve a "random-walk" algorithm to be a bit more efficient.

A third option (by far the most ambitious) was to add some kind of custom LIDAR unit (for SLAM - so the robot knows where it is and where its been), plus a form of machine-learning via OpenCV to detect vegetation vs non-vegetation. I've seen some papers on how this is done (vegetation detection, that is) - replicating it would be very difficult, but in theory possible at a hobbyist level. Provided I spent the time. Again, laziness. Lol.

Likely, a combination of all of the above methods would be needed to make it work somewhat well. It likely would still need to be baby-sat as it worked (better than doing the work yourself, but still not fun here in Phoenix in the summer!). And, it still wouldn't trim the bushes or trees for you.

I currently pay a maintenance outfit to do my front and back yard every couple of weeks for $60.00; honestly, it's a bargain.
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: Jantje on Jun 08, 2014, 10:12 pm
you can staple the wires on the ground. If the grass is short enough when you place the wire it grows over it.
No need to dig :-)
Jantje
Title: Re: Using invisible dog fence as boundary for lawn mower robot
Post by: CrossRoads on Jun 10, 2014, 01:57 am
You have grass in Phoenix?  Isn't that the land of rock/stone yards so no watering 8)
You don't need to dig to bury the wire. Just insert a flat spade enough to make a trench and have your helper stuff it in as you go.