Author Topic: Request Robotic Lawn Mower (Read 27897 times)

airman00 · « **Reply #30 on:** September 07, 2008, 11:36:06 AM »

Quote from: ryan on September 07, 2008, 10:56:14 AM

Will a wire of 100 m be suitable for this circuit?

what gauge ( thickness) ?

ryan · « **Reply #31 on:** September 07, 2008, 10:07:24 PM »

Hmmm 18

ryan · « **Reply #32 on:** September 12, 2008, 12:19:29 AM »

I have obtained a transmitter and receiver schematic . I think it also includes a base station. Are the schematics alright? Also what inductor and capacitor values should I use for the receiver part? (to obtain a better resolution right click on image and select view image)

ryan · « **Reply #33 on:** September 18, 2008, 09:09:57 AM »

Any ideas for the above circuit please?

Admin · « **Reply #34 on:** September 18, 2008, 09:33:10 AM »

Your circuits require a more complex AC analog analysis, which is beyond the skills of even most electrical engineers.

Assuming you followed the datasheets correctly, just bread-board it up and see what happens. The other option would be using a simulator.

ryan · « **Reply #35 on:** September 18, 2008, 09:42:34 AM »

Which simulator can I use please?

Admin · « **Reply #36 on:** September 18, 2008, 09:52:51 AM »

You forgot to search

circuit simulator

ryan · « **Reply #37 on:** September 18, 2008, 10:02:35 AM »

Thanks Admin

tokr · « **Reply #38 on:** October 03, 2008, 03:09:21 PM »

I've been thinking about building a similar robot, though not for lawn mowing but for pushing a broom around a large gym. Because I know nothing about robotics I was trying to think of a simple way to do this.

Would it be possible to guide the robot all over the lawn/gym once and the next time it could just follow this pattern from memory? Would that be simpler or am I just naive?
How difficult would it be for a beginner to build a robot like this? what might it cost?

Spoil9 · « **Reply #39 on:** October 03, 2008, 06:11:11 PM »

Does anyone here read ROBOT magazine? This months issue had a short article about a guy who built and is trying to sell a RC lawn mower.

ryan · « **Reply #40 on:** October 07, 2008, 11:29:19 PM »

Err so far Have tested the motors and the driver board and it's working. Hmm how can I make a front bumper sensor using two microswitches??

Spoil9 do you have the article?

Admin · « **Reply #41 on:** October 07, 2008, 11:49:01 PM »

Quote

Hmm how can I make a front bumper sensor using two microswitches??

Not the best of my tutorials, but its all here on SoR

http://www.societyofrobots.com/sensors_tactbumpswitch.shtml

ryan · « **Reply #42 on:** October 08, 2008, 09:44:46 PM »

Thanks Admin. How do I do the mechanical part of the bumper?

Admin · « **Reply #43 on:** October 08, 2008, 09:55:31 PM »

What do you mean?

Just buy a microswitch, use the screw hole to attach to your robot chassis, then tape a chopstick or some stiff wire to the switch part.

ryan · « **Reply #44 on:** October 09, 2008, 12:29:36 AM »

Great Thanks Admin

I'm having trouble justifying the use of a dc motor for the mowing system? And how do I prove that I need a motor of a particular capacity?

Admin · « **Reply #45 on:** October 10, 2008, 05:31:06 AM »

Quote

how do I prove that I need a motor of a particular capacity?

http://www.societyofrobots.com/RMF_calculator.shtml

ryan · « **Reply #46 on:** October 10, 2008, 07:18:09 AM »

Can I use that calculator to calculate the dc motor I need to cut the grass?

Admin · « **Reply #47 on:** October 10, 2008, 07:53:44 AM »

Nope . . .

That involves some dynamics calculations.

Also, to calculate, you'd have to know the torque required to cut grass (I doubt a google search will answer that!)

Spoil9 · « **Reply #48 on:** October 10, 2008, 06:14:52 PM »

Ryan,
Sorry I can't find the article on line anywhere but it does not describe how he built anything other than saying he's using a 4 channel receiver that is wired into a MCU that controls 2 separate motor controllers and all that is under a steel box to protect it from the elements.
Like I said, nothing fancy, but thought I'd throw it out there.
What you're doing seems to be much better a design though so keep up the work. Sounds like you're making good progress.

ryan · « **Reply #49 on:** October 15, 2008, 12:29:42 AM »

To Admin:
Yep i did some search no results..lol

To Spoil9:
It's ok yep they'll not reveal everything in the magazine. Thanks for your encouragements

ryan · « **Reply #50 on:** October 15, 2008, 11:43:46 PM »

The power regulation schematic is it applicable to a 12 V sealed lead acid battery?

Admin can you please help me with a mechanical engineering reason why the wheels on the picture provides more traction?

Admin · « **Reply #51 on:** October 16, 2008, 09:19:23 PM »

Quote

The power regulation schematic is it applicable to a 12 V sealed lead acid battery?

Yeap, but don't regulate voltage to the motors, just microcontroller.

Quote

Admin can you please help me with a mechanical engineering reason why the wheels on the picture provides more traction?

Those spokes dig into the ground, almost meshing as if the ground was a linear gear.

ryan · « **Reply #52 on:** October 17, 2008, 10:31:59 AM »

Quote

Those spokes dig into the ground, almost meshing as if the ground was a linear gear.

Thanks a lot admin. Err is there a way to justify it in terms of mechanical formula etc??

Admin · « **Reply #53 on:** October 19, 2008, 05:17:16 AM »

Yeap there is . . . but too lazy to go into theory

Basically, the friction and force angle to the surface changes. If you draw a FBD, it'll become more obvious.

ryan · « **Reply #54 on:** October 24, 2008, 03:06:58 AM »

Can you help me a bit more please Admin? What do I have to prove? That the friction increases with this type of wheel than with a regular wheel?

Admin · « **Reply #55 on:** October 24, 2008, 03:20:55 AM »

Why do you need to calculate friction? I don't understand your last 3 questions . . .

If you want to calculate it, or anything mechanical, you *must* draw an FBD as the first step. I'm not going to do it for you

madchimp · « **Reply #56 on:** October 24, 2008, 03:35:42 AM »

What's an FBD?

Admin · « **Reply #57 on:** October 24, 2008, 04:09:20 AM »

madchimp, there is a link to a definition just a few posts up

(and always use Google/search first!)

ryan · « **Reply #58 on:** October 24, 2008, 10:00:55 PM »

I got this from wikipedia

Traction refers to the friction between a drive member and the surface it moves upon, where the friction is used to provide motion

That's why I was referring to friction

Ok I'll try the FBD though I'm not sure how to prove it

jamort · « **Reply #59 on:** November 20, 2008, 08:14:52 PM »

for the under ground fence you could get something like the shock collars they put on dogs so when the dog got over top the wire it would shock him..... also what the yard your cutting would have an influence on it ex. if the yard is square it would be real easy but if theres objects you have to make the robot get around those objects and still cut all the grass.... Also if its a weird shaped yard and you go with burrying fence having several places for it Differn block so it would cut one spot then you would place it in the next and so on so forth until your done....
Good luck!

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Author Topic: Request Robotic Lawn Mower (Read 27897 times)