Author Topic: Robot arm trouble (Read 3957 times)

Mcrich113 · « **on:** March 02, 2008, 08:02:36 PM »

Hey guys!
Listen, I'm fairly new to robotics and need help. Iwant to make a robot that is like an RC car and has a robot arm (got the idea from the robot arm tutorial

.Sounds chalenging right?And it is, I am trying to make the arm like a humans, 2 servos for shoulder joint(one to move it around and another to help it dive foward), one for the elbow joint, 2 more for the claw, and 4 for the wheels ,it seems as though i got it right, WRONG

. I have lots problems. First off, from what I have descipted,do i have enough servos $:-\$ , second, i want the robot to turn, how do I do that, also, what matreial do i use so the arm will move right(Tell me something better than cardboard but not as heavy as wood, finally , and most important, WHERE DO I GET GOOD ROBOT PARTS AND RC THINGS CHEAP

?.

thanks Mcrich113
P.S. oh and this place rocks

!

airman00 · « **Reply #1 on:** March 02, 2008, 08:13:17 PM »

welcome to the forum

first we will start with the R/C part
I'm thinking two modified servos and a caster wheel , giving the vehicle differential drive
then an r/c receiver going to the microcontroller which will translate the signal to movement

as for the arm

do you want something like

why do you need so much servos?

You realize that you can't possibly control all these servos yourself on a remote
also a lot of the servos you mentioned are overkill. You need one servo to bend the arm , one to tilt the gripper, and one to actuate the gripper. Thats it

Mcrich113 · « **Reply #2 on:** March 02, 2008, 08:31:04 PM »

hi guys
Thanks for the reply airman00! Now on to buisness, thanks for the sevos thing, i bet it will help, as for the microcontroler, slight problem, not that I argue with the idea, but i don't have the time ,money, and exprience to do it! I know its written in the 50 dollar robot tutorial, but I just cant writ the program(i would have to write that myslef right?) also, i cant get parts. also I was hoping someone could help me here, I want to know if there is a good robot club in torrance,cailfornia.
Thanks! Mcrich113

airman00 · « **Reply #3 on:** March 02, 2008, 08:34:08 PM »

well Mcrich113 , your situation is pretty bad

you want to build something like this

but you have no parts, no money, no experience , and not time

california has a lot of robot clubs. You'll need to search around

Do you have a budget at all?

Mcrich113 · « **Reply #4 on:** March 02, 2008, 08:46:26 PM »

Okay, look I have a budget of $25 (I have lots more but my bother won't let me use it),Problem? WHERE DO I GET PARTS?!?!?I live in los Angles in the west section of torance , cailfornia , i need to get parts from some place that is easy to get to, and if u really think i need a microcontroler than okay, just tell me what types of parts I need and I'll get it

P.S. Ill see if I can get more okay?

airman00 · « **Reply #5 on:** March 02, 2008, 08:56:42 PM »

since you have such a low budget , use ebay and surplus stores. Junkyards are good for parts as well

search the forum to see what stuff can be taken from household appliances

Mcrich113 · « **Reply #6 on:** March 02, 2008, 09:04:10 PM »

Hey guys
all right, first of, i think i can scrape together$40 dollars, also,My mom has tons of compter junk that just sits in my garage, I have two real old printers, two old computers, and plenty of speakers, i bet this helps right?Better than dumpster diving for sure!

oh and to all u people only reading this, HELP ME,

Admin · « **Reply #7 on:** March 03, 2008, 08:55:23 AM »

Mcrich113, you will need a bigger budget for what you want to do, $100+

How about something like this?
http://www.societyofrobots.com/robot_asme.shtml

Mcrich113 · « **Reply #8 on:** March 03, 2008, 07:13:24 PM »

Hey guys!
Thanks for tip admin! I'll get 100 now for sure! I am still having doubts though, I am going to use the caster wheel still, but I am going to add the bucket too, in my last reply I said about computer junk can anyone tell what I should look for there? also, I want to Know the best parts that are good and inexpesive, I also want to know what kind of Remote control I need,

Thanks Mcrich113

Trumpkin · « **Reply #9 on:** March 03, 2008, 08:35:44 PM »

get some HS-311 servos because they are so cheap. what torque do you need for the arm?

Mcrich113 · « **Reply #10 on:** March 04, 2008, 07:08:51 PM »

Hey guys!
I actually already planing on using those, But in my other post I said I had scanners, someone said they had stepper moters, what are those?
the troque I want is prety moderate ok?

Thanks Mcrich113

ed1380 · « **Reply #11 on:** March 04, 2008, 07:18:24 PM »

google.

they're most likely bipolar so it'll be a bit harder to control them

Mcrich113 · « **Reply #12 on:** March 04, 2008, 07:48:29 PM »

Hey guys!
Are you sure?Now I feel clueless

. I want them cheap, but if they are thathard to control, I am going to need another opion from someone else,still, thanks!

Thanks Mcrich113

paulstreats · « **Reply #13 on:** March 06, 2008, 10:36:05 AM »

The only way to find out what type of motors they are is to take them out and count how many wires are connected to them. If theres 4 then they are bipolars - and will need 1 full bridge driver for each motor

izua · « **Reply #14 on:** March 06, 2008, 12:40:00 PM »

Quote from: paulstreats on March 06, 2008, 10:36:05 AM

and will need 1 full bridge driver for each motor

i'd say two H bridges per motor. bash me if i'm wrong.

paulstreats · « **Reply #15 on:** March 06, 2008, 02:11:20 PM »

Full bridge drivers usually contain 2 h-bridges

Mcrich113 · « **Reply #16 on:** March 06, 2008, 08:55:17 PM »

I agree with Ed1380, I think they 're bipolar, how many people have seen different?

rahul · « **Reply #17 on:** March 08, 2008, 12:59:12 PM »

I guess you need a solid plan first. draw something on paper that suits your needs. It will let you decide, what and how much material you exactly want, where to place motors, where to place batteries, what grippers will you need and above all--the dimensions of the robot's arm that would effect the stability of the robot. Then begin building it, taking every task stepwise. will be easier to work and you wont be wasting time doing things that u really dont need to do.

Nice Forum. The guy(s) who made it did a very outstanding task !!

Trumpkin · « **Reply #18 on:** March 10, 2008, 08:38:28 AM »

Don't wast your time and money messing around with those stepper motors.

Quote

Nice Forum. The guy(s) who made it did a very outstanding task !!

It's not that hard to make a forum. There are plenty of providers for free forums.

rahul · « **Reply #19 on:** March 10, 2008, 09:23:09 AM »

Quote from: Trumpkin on March 10, 2008, 08:38:28 AM

It's not that hard to make a forum. There are plenty of providers for free forums.

it is not difficult to make a forum but it is not easy to make one with loads of info to support the "beginners" in robotics community !

Off topic? sry !

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Author Topic: Robot arm trouble (Read 3957 times)

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