Author Topic: Anyone know were i can find these? (Read 4389 times)

jakx12 · « **Reply #30 on:** May 27, 2009, 04:21:58 PM »

yes i was going to get them. I need one servo for the base so it can turn 180 degrees, ill attach a ir sensor on it to find on object but ill attach the sensor at ground level. It will basically find an empty space and keep that number recieved as a variable, lets call it avrg. The ir sensor mounted on the turret will be right underneath the robotic arm at all times. So say the sensor finds a large difference from the avrg variable to the readings of the ir sensor, this would be a object, and therefore the robotic arm will be pointed in the right direction. There will be an ir sensor mounted on the gripper. So the gripper will then touch the ground and move up until the ir sensor realises the object is not there any more. As the microcontroller will know the distance travled per pulse to the servo. And the servo would have moved a certain amount of pulses until the ir sesnses there is no object in the way, it ill add the distance to the thickness of the gripper this tells us how tall the object is. We will halve this length and then move the gripper to there (which is the middle of the object) and it will try and grasp the object. There will be a pressure sensor mounted on the inside of the gripper so it will be able to realise when its made contact with the object and so it will be able to pick up delicate things like balloons.
However if this method finds nothing on the table, chances are the ir sensor mounted to the base is too high compared to the hight of the object, for example it maybe a pencil. As the gripper will be able to turn 360 degrees it will not be like this: \/ but like |. If you get what i mean?! lol. Using the ir sensor mounted on the gripper it will do the same thing as the ir sensor on base, basically it will find the object by doing the avrg thing and will find its length, halve it so it grabs the middle of the object and picks it up.

I will also make it so the arm can be controlled by a computer if i want it to

Thats a basic outline of how it works.

jakx12

galannthegreat · « **Reply #31 on:** May 27, 2009, 07:04:49 PM »

That servo definatley overpowers a lot I know of, and for its price, wow, that's a good deal!

I can't wait when this thing is done, it sounds amazing!

SmAsH · « **Reply #32 on:** May 28, 2009, 12:21:49 AM »

wow that seems complicated...
we want drawings...

jakx12 · « **Reply #33 on:** May 28, 2009, 02:36:11 AM »

lol i just woke up ill put the simple drawings up (the ones i was telling smash about). But i need to order stuff and as im in the uk it will take time for parts to arrive, and i havnt ordered them yet. But i dont really have a deadline

jakx12

SmAsH · « **Reply #34 on:** May 28, 2009, 05:32:12 AM »

there are uk suppliers aren't there?
or are the parts you want only available outside uk?

jakx12 · « **Reply #35 on:** May 28, 2009, 05:56:29 AM »

there are uk suppliers but they tend to have nothing

. I found some really good servos on ebay uk so ill get them soon, i have the perspex plastic, i need two ir sensors and some stuff for the gripper and the base, all of which is from america.
Oh my scanner is not working so i cant get a picture up anytime soon

. If i have time ill do a quick sketch on my comp probably wont be cad.

SmAsH · « **Reply #36 on:** May 28, 2009, 06:10:42 AM »

ahh yes, the dreads of not living in the u.s...
what are you planning on making the arm and gripper out of?

jakx12 · « **Reply #37 on:** May 28, 2009, 08:59:18 AM »

well for the frame i found some perspex plastic in my attic which is pretty light and can be cut by a hacksaw so ill use that

kpmcgurk · « **Reply #38 on:** May 28, 2009, 02:40:23 PM »

It looks like you are going in a little over your head, is this your first robot? I know you have alot of sweet ideas, but you should just start out simple, and then add on all of the fancy sensors and jaz! If this isnt your first robot, and you know how to program and you have a fair amount of experience, ignore what i just said

SmAsH · « **Reply #39 on:** May 28, 2009, 03:28:39 PM »

it is a lot easier to assemble the arm with the servos in it and get it moving first without any sensors on there...
kpmcgurk, a lot of people want to build projects that are way over there head so i know where you are coming from but this project does not seem too complicated... now if he was using vision it would get tricky!

jakx12 · « **Reply #40 on:** May 28, 2009, 03:48:13 PM »

kpmcgurk im pretty experienced with robotics. I have built many autonomous systems and adaptive mapping robots. Sadly i havnt come round to doing a diagram for you guys as all my main ones are on paper. But sadly i just found out that iv lost all my codes and programmes etc so im pretty annoyed write now

but iv got the extra 20$ i needed and will be ordering stuff in a couple of days

After the arm im going to build a snow shoveling robot

. It will be remote controlled.

jakx12

kpmcgurk · « **Reply #41 on:** May 28, 2009, 07:18:19 PM »

HAHA, great, but here in wisconsin, rarely will we get so little snow that it can be shoveled with a robot

unless it has a lot of torque(i.e. no servos). that sounds like a fun project, if you make it really cool, it would be neat! program it to know your driveway, so you can just set it there, go make coffee and shower, and 20 min. later you will be shoveled!!

SmAsH · « **Reply #42 on:** May 29, 2009, 02:05:16 AM »

that would be a great way to use mapping!
i cant wait to see some pics, but no rush...
sorry to hear about the codes man $:-\$

jakx12 · « **Reply #43 on:** May 29, 2009, 03:22:20 AM »

lol in london we got NO snow but i know some people who live in switzerland and have 'suggestetd' it. And yh, i wouldnt be using servos lol.

SmAsH · « **Reply #44 on:** May 29, 2009, 03:56:37 AM »

not to be mean or anything but most people wouldn't want to sit there and control a snow shovel when they can go out and do it themself.
have a look into making an autonomous version that the user can set up a perimeter to stay in with ir or something..

jakx12 · « **Reply #45 on:** May 29, 2009, 05:17:30 AM »

i suppose, but i think it would be pretty fun to control a really powerful robot

. But im sure i could get it to do it by itself. Perhaps by entering in the dimensions of the drive way or something.

SmAsH · « **Reply #46 on:** May 29, 2009, 05:22:35 AM »

there are a few robotics lawn mowers that user this "invisible fence" stuff that you place around and it emits ir or something that the robot can detect...

jakx12 · « **Reply #47 on:** May 29, 2009, 05:25:14 AM »

thats not a bad idea, but im sure its not particularly cheap. As the robot would probably be only used for the people i know etc, whenever id lend it to them i could just put dimensions in. But i still like the idea of the ir fence

. Do you know where i could get some?

SmAsH · « **Reply #48 on:** May 29, 2009, 05:32:40 AM »

http://lmgtfy.com/?q=invisible+fence
it works on the same principle as these dog collars.
except you don't want to shock the mcu

jakx12 · « **Reply #49 on:** May 29, 2009, 05:34:29 AM »

thanks, nah i dont think ill want to do that

.

kpmcgurk · « **Reply #50 on:** May 30, 2009, 07:34:08 AM »

You guys are giving me some Great Ideas here!!! view an animation that our robotics team made for this problem!!!

http://3dhaze.com/first/2008/2008.htm

jakx12 · « **Reply #51 on:** May 30, 2009, 02:30:37 PM »

very cool robot, thats exactly what id like to do or just a 'shoveler'

.

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