Lawnbott "door"?

[jzawacki]

Now that my kids are old enough, our (chain link) fenced in yard isn't needed to "keep them in".. 

Any thoughts on making a flap in the fence like a doggy door?  Right now, I'm thinking of just cutting a hole on each side of the fence and running the wire through the middle of it.. making sure the bot can get to and from the front yard through the doors.. and then later, going back and installing a flap.  Originally, I was thinking of one with a spring, but the last thing I want it to do is to trip the bump sensor.  But, even just a hinged flap is probably fine.

[RoyMercer]

Have you seen robolawn's RoboGate from Canada? http://www.robotlawnmower.ca/robogate.cfm  I am sure it cost much more than your idea though.

I suspect the material you use will need to be light enough as to not trigger the bump sensors. And something that will last in the weather. We bought some stuff from Grainger many years ago to make a cheap door to keep the hot and cold air out. You might see this stuff in a grocery store. Strips of rubbery plastic you walk through. I don't know how well it will hold up in the weather though. 

[toolbelt]

Here is an idea that may work.  I've never built one so give it some thought before cutting your fence.  The idea is to build a 'box' on both side of the fence so you end up with a tunnel that is long enough to stop most dogs from crawling through.  Maybe if you hung straps of material down from the top of the tunnel it would also help in deterring them from crawling through.

I show one tunnel for both outbound and inbound wires.  Just narrow the width of the tunnel for single wire.

[Namocsid]

Have you seen robolawn's RoboGate from Canada? http://www.robotlawnmower.ca/robogate.cfm  I am sure it cost much more than your idea though.

I suspect the material you use will need to be light enough as to not trigger the bump sensors. And something that will last in the weather. We bought some stuff from Grainger many years ago to make a cheap door to keep the hot and cold air out. You might see this stuff in a grocery store. Strips of rubbery plastic you walk through. I don't know how well it will hold up in the weather though. 

I was in contact with Moe about a RoboGate over a period of several months and was willing to purchase one.  He never did get them in stock and it was one excuse after another.  I eventually quit trying.  I'm sure it's a great product...if you can actually get one.

[jzawacki]

Well, last I heard about the robogate, it was going to be like $500 and they were planning to use "cheap" parts from China.

Either way, I did some testing this weekend just to see how wide the opening would need to be and it appears to be about 19".  Which is basically 1" on each side of the bot.  I ran it through the "hole" half a dozen times or so making it smaller each time till it seemed to be just right.

http://www.youtube.com/watch?v=Hc6NYnAOmrs

Right now, I'm actually thinking of cutting two doors.. One on each side of the yard.  This will make it so that I can remove the parameter wire along both sides of the fence and the bot will just run into the fence instead of the wire (as it currently is setup).  For the flap, I was originally thinking of just copying a doggy door with just a piece of wood or plastic hinged at the top, but maybe I can use the chain link section I am cutting out and just hinge it.  This will reduce the chances of wind blowing it around.

As for keeping animals out.. didn't really think of that..  I'll give that some more thought later, as I'm not sure it matters right now anyway, as we keep our driveway gate open all the time anyway, but if I get into it, maybe I'll look into some kind of automatic latch system that will follow the robogates design and unlatch when the bot is near.  Not needing a motor to actually open/close the door will keep the cost down and should provide the same amount of security.  At the same time, being that it doesn't need to open/close may allow the use of passive technology such as RFID to be on the bot so that it doesn't need batteries for a transmitter.  In theory, a solenoid could be used to unlatch the door, and if it's low enough power, maybe solar could charge a battery so external power isn't needed.  I'll post what I figure out, as my brother does RFID for IBM and has also worked on some solar projects.

[toolbelt]

If your opening is just wide enough for the bott to get through then the bott can't get through the gate unless it is either going to the next area or returning.  To test this try driving stakes 9 1/2 inches away from the wire, perpendicular to the wire and see if the bots makes it through.  During normal mowing it will hit the stakes (fence) or the wire causing it to turn back.  It could get caught on the wire at the front wheel openings but if you framed the opening with a 1 x 3 (pressure treated or Cedar) that should stop that.

[jzawacki]

Agreed, but why would you want it to go from a back yard to a front yard and it not be different zones? (Just asking for conversation)  I mean, I wouldn't want my bot out in the front mowing unless I told it to be there.  Of course, for me, this is all for my personal gain (not having to manually bring the mower to the front yard to mow).

But, for more of a general conversation, I like the idea of a single door as toolbelt made reference (I'm still planning on two doors, one on each side, so they will both be strait lines for the parameter wire), but in that example, wouldn't the 90 degree parameter wire bends be to much?  If it is along a fence, one side is going to have to do a 90 degree turn to get through the hole.  Again, this is for conversation, as I have a few 90 degree bends in my parameter wire and the bot doesn't seem to have any problems following it, but I don't know how it would react if it had to squeeze through a hole next to it.  I guess I could test it out.. because my next "big idea" would work 10x better with a single opening in the fence.

[toolbelt]

I didn't make my self clear.  I was trying to say that your idea of limiting the size of the hole to just 1 inch larger than the bott should work great.  It couldn't escape to another area is what I meant to say.
As far as doing a 90 degree turn all you would have to do  is move the wire out about the length of the bott (like trucks do when they make a 90 degree turn) then back through the opening.  If the bott is mowing in that area it would still run into the wire or fence and not be able to escape.

[jzawacki]

Toolbelt, based on your drawing, what would you think the spacing should be between the parameter wires so that the bot will follow it in both directions through the door?  In theory, the opening should only need to be 8" from the parameter wire on either side.  So, if the parameter wire needed to be 3" apart, the opening would be 22" wide.

[toolbelt]

I have had the bot escape past the top of a 'boot' which was only 4 inches wide so 3 inches between the wires should work.  It's following the wire so it's not going to be off that much.

One inch    from side of opening =1"...8"...W..3"..W...8"...1" =21 inches wide
Two inches from side of opening =2"...8"...W..3"..W...8"...2" =23 inches wide

I would go with the smaller opening as you can always enlarge it.

Thinking about it, if you don't need the 'box' you could frame the opening with 1x3 boards.  If the bot hit the edge it should slide off.  I've seen mine get stopped by a bush limb, hesitate for a couple seconds then continue on.

[jzawacki]

3" sounds good.. My only concern is the distance that it is blind to.  I know running them parallel through the pegs makes them invisible to the bot and wanted to make sure it wouldn't pass right by the door, following the other side.

As for "finishing" touches.. because it's a chain link fence, I'm currently just planning to run a metal rod around it through the links and hopefully running the ends into the ground to make it a little more sturdy.  Being the prototype stage, I may just bend the rod, pound it into the ground, and zip tie the fence to it.  I know I need to do something because chain link is pretty flimsy.

[toolbelt]

Something like this should work.  You can always adjust the gap between the wires.

[jzawacki]

Links "scraped" from off topic posts in other thread:

POWER PET TM  electronic pet doors:
http://www.petdoors.com/power-pet-automatic-pet-doors.html

PetSafe’s Electronic Dog Door:
http://www.discount-pet-superstore.com/dog_doors/electronic_dog_door.htm

Robo-gate:
http://www.robolawn.com/robogate.cfm?cfid=4311995&cftoken=61284078

Another Power Pet link:
http://www.hitecpet.com/powerpetdoors.html

----

What I like.. so far, the cost and potential ease of modification.  Most seem pretty simple as to how they operate.  Ones that use batteries easily make a better fit for our application.  Though, I don't know how long the batteries last, or how they would hold up in the weather.

What I don't like.. is how they all seem to have a motorized component.  Maybe motors are the best solution to the problem, but I'm hoping to come up with an idea that minimizes the needs for batteries (on the transmitter side) and doesn't use a motor.  Right now, I'm think something like a solenoid that would work like a deadbolt.  I'll just have to wait and see.. We had pretty bad storms go through, so playing with this has went to the bottom of the list under house repairs.

[RobotLady]

jzawacki, thanks for the consolidation of info!  Until the Wiki is ready, every little bit helps!

[jzawacki]

Welp, not to just bring up a dead thread, but I just cut the hole in my fence and have printed out toolbelts suggestion for the parameter wire to try it out..  so.. just an FYI.  I'll try to post pics as I go along.

Edit:

Ok, instead of pics, I did some video.  First two are me messing with the bends and spacing.  I probably did this 15 to 20 times before it worked right.  And guess what, it turned out to work just like toolbelt said it would.  

Test 1

Test 2

Test 3

Test 4

Next will be to clean up the hole and figure out how the flap is going to work.  Right now, I believe I can just create a frame for the chain link around the edge of the hole and then create a frame for the chain link that I cut out, slap a "hinge" on it (which will probably just be some wire for now) and see how it goes.  I am hoping it will be light enough that the bot doesn't even feel it, and that it won't catch the charging nuts on the top.  We'll see.