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School project – mechanical hand
This article will have an overview of our school project (term 2/6). There are three heads on my group. Our goal with this project is to make a mechanical hand which can move it fingers like a real human hand, electronically controlled. Even point at, pick and crush things!
Before we decided what project we wanted to do, we had several ideas. A sensor based 4wd vehicle to mention one of them. After setting our goal on making a mechanical hand we did our research on google search/images. We only found a single hand (image below) which seemed something we could do in our time, among many other professional vendors.
It is required by us to setup a budget and plans for the rest of the project. All groups in my class needs to be finish by week 21 when the presentation is.
Me and my group are finish developing the hand and making it. We also got our plans for each week ready. Luckily, we reached our milestone for this week, were we wanted to figure out signal’s need for the RC-servos.
The hand is going to be drifted with five Futaba 148S servos, they cost about $19 each and provide 4.1KG of torque with 6.0v and a twist time of 0.19sec/60 degrees. So far, our budget is on $94, but it may increase by a few bucks due to some small components we might need.
We are still working on the sinew/rod’s before installing servos. We might just clean it for all welding points as well.
Update #1
We have now figured out the servo signals and created a physical servo controller. We are using the 555 timer, two actually, because we had an issue with only using one. It didn’t create a stable output before 30 seconds after start. The
surrounding components, capacitors and resistors are our variables, changing the signal length.
We also did make a counter using two J/K FlipFlops and a dmux to convert the signals.
The circuit’s for this hand is so complex, that we decided to program it all into a Altera card. Logic scheme will be available later when we have completed the project.
Image album.
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| School project – Mechanical hand |
Video of hand in action.
Finger control.
Bottle holder.
Tags: $19, 148S, 3.3v, 4.1kg, 6.0v, Futaba, hand, hisf, mechanical, metal, project, RC, school, servo, torque
August 25th, 2009 at 10:25 pm
[...] We`re about to choose project at school, maybe this is a step up from our mechanical hand? [...]
September 10th, 2009 at 12:12 am
Hello:
I would like to ask you some points about your project. I’m a student myself and I’ve a project very similar to yours. I would like to know if it’s possible to give me some information about the construction of your hand. I’ve been watching your videos and I can’t understand the joints in the fingers, specially the welding parts that helps to have movement to each finger.
I hope you can help me, because I want to build a hand like the one you did.
Greetings, Manuel.
September 10th, 2009 at 9:07 am
Hi there
Did you view all the pictures of the hand? If you take a look on the pictures here http://picasaweb.google.com/v.hammerseth/SchoolProjectMechanicalHand you can choose a picture and zoom in on it. You should be able to see how we did it, if not, I will explain it for you:)
September 15th, 2009 at 12:17 am
I didn’t know you could zoom the pictures
Thank you; I hope you could help me for any question I could have during the construction of the hand.
November 10th, 2010 at 9:41 am
Hey man,
I am also working on a project of an artificial hand powered by Nickel Titanium wires. Almost the same as yours by the actuation system is different.
I am now interested to connect this device to the neural-system of a human being.
Let me know if u can be part of this.
my email: longela@gmail.com
Simon L
Cape Peninsula University of technology
South Africa
November 10th, 2010 at 10:26 am
Simon Longela: I have sent you an email.
December 23rd, 2010 at 6:38 pm
Hiii I would like to kno the exact materials that you used
I intened to also a mechanical hand for a school project
but I dnow how to control it …
Thank you for your help..
December 28th, 2010 at 12:21 am
Hey,
I am a student also, and i am working on creating a human like robot, but i am stumped on the hand. I have created a hand similar to yours but mine doesnt open up after (ie. it creates a fist, and then there is nothing to pull it back to its original position). Did you face this problem? how would you suggest i fix it?
March 22nd, 2011 at 8:27 pm
Hello! Your special case’s manufacture lets me really attracts
I did not know that has is honored to you studies!
Because of yours manipulator’s movement! Let me really likes!
I very want to study to you! Did not know that you are willing to teach me!
I from the Taiwan 25 years old am the student at present
My mailbox:andy711025@hotmail.com
Admires you the student Roger
March 22nd, 2011 at 8:47 pm
@Haiidy
Hello
We used stainless steel, some wire for finger control and five servoes.
March 22nd, 2011 at 8:50 pm
@Raj Singh
Hey
You can use the same technique used on this hand. You might be able to view it on the pictures from my gallery. Use wire with tubes and give them fixed positions. If the wire can’t go anywhere the finger will have to follow and will therefore close itself.
March 22nd, 2011 at 8:52 pm
@Roger
Hello!
Thanks.. I think. Don’t quite follow your English. Do you have a specific question?
March 24th, 2011 at 4:58 pm
hi there i’m a student myself on a similar kind of project i have a doubt in your circuit board can you give me a clearr view oon that??? i would be greatful if you do so
March 24th, 2011 at 7:12 pm
Hello
Don’t mind this circuit board. To be honest it’s a hell to work with. I’d recommend you to use arduino
May 26th, 2011 at 11:28 am
Great artical, I unfortunately had some problems printing this artcle out, The print formating looks a little screwed over, something you might want to look into.
September 18th, 2011 at 1:22 am
hey, i am working on the same project but still not clear about your mechanical design . can you please send more details to me..
September 18th, 2011 at 9:56 am
Hello Azhar.
I don’t have much documentation on how the mechanical work is done, but I remember it well. Check out my answers in the relevant youtube videoes and the comments in this page and I think you should have enough. Ask again if it’s not sufficient.
- Vegard
October 2nd, 2011 at 6:59 pm
Hi Vegard,
Do you think it’s possible to use only one servo and connect 4 wires to each other and let the thumb be fixed (in an alternate position then yours perhaps). So that i can close the hand with only one servo. Budget is limited and also not every finger is supposed to move seperatly. In this case it will be easier to let the wrist rotate with a different servo.
PS: what kind of wires did you use or doesn’t the stiffness of the material influence the fluent movement of the fingers
TY!
October 8th, 2011 at 3:41 am
ESTA BIEN COOL TU PROYECT BROTH
October 9th, 2011 at 6:34 am
i’m making something that’s like iron man’s glove. ther servo motors moves with the movements of my hand.
October 15th, 2011 at 8:31 pm
Hello
Sorry for this late replay. I didn’t see the post before now.
It is possible if you have a strong enough servo.
November 28th, 2011 at 5:36 pm
Hi
I am from india, your project is awesome, but i don’t know how this fingers retract once it is compressed. Please let me know the same, as i could not find any such stuffs that are attached to any of the part.
warm regards,
Kumar
November 28th, 2011 at 8:13 pm
Hi Kumar
The fingers retracts by being pushed by the wires inside the fingers. It’s important that the wire is in a fixed position to make the fingers act as they do.
December 12th, 2011 at 7:20 pm
So the wires act like springs to move the hands back in the original position?
December 12th, 2011 at 7:47 pm
Kind of, but I would’nt call it springs. It’s just push’n'pull.
December 21st, 2011 at 7:26 am
I only ask because i have been looking into building a robotic hand clock. The hand will count to twelve using a certain method and there will be a screen to display the minutes. I have attempted to build a cardboard model before purchasing anything and have ran into alot of problems. First, i have no idea how you were able to sink the fingers so that the upper part bends, then the middle and finally the joint connected to the hand. So far my first and second joint bend at the correct times but then the upper wieght just pulls everything down into a mess. Secondly, i do not understand how you are able to get the fingers back after flexing. is the string more like a plastic wire? Thank you for your help
December 21st, 2011 at 12:52 pm
Matthew: Nice to read about your interest. The fingers are mostly mechanically synced. The wire has to travel same length on all fingers, almost. We used bicycle wire.
I think maybe cardboard may be to weak for the forces which are required to close the fingers. There are quite some tension.
December 22nd, 2011 at 1:57 am
You are completly right. I got the model to be able to close into a fist, but i could not devise a method for them to re-extend. I may have figured it out by using a bungie cord but the strain caused my model to collapse into a mess. I guess what I dont understand is the bicycle wire and your method of leting them contract as well as extend. Do the servos really have enough power to push the wieght of the figures back to straight? And there lies another question. To contract and extend a finger, does the servo have to be powered to do both motions? In other words, the servo is not relaxed when the finger extends?
Like i said before thank you for your help. I just started this project with no previous knowledge of circuits and would like to finish it before winter break ends in a month. I appreciate the information!
December 22nd, 2011 at 7:35 pm
Pushpulling the fingers are quite easy and the servoes are way stronger than this. One servo is dedicated to it’s finger and moves front and back.
January 7th, 2012 at 12:53 pm
hi, can you say me what’s the dimension of hand???
January 7th, 2012 at 1:05 pm
Hello
What dimensions did you want? The overall hand has the same size as a grown man’s hand.
January 9th, 2012 at 3:03 pm
dexa eu perguntar tenho que fazer meu TCC(Trabalho de Conclusão de Curso) quero fazer uma mão robótica vcs podem me ajudar sou do brasil por favor me ajude ?
January 9th, 2012 at 3:17 pm
You will have to state your question in English if you want a proper answer.
January 31st, 2012 at 7:19 pm
Did you use some chip to stop the servos when they have done one or two laps?
Sorry for my english.
January 31st, 2012 at 7:53 pm
No, I just wrote it in the code.
February 1st, 2012 at 10:01 pm
hi :
i m doing project on robotic arm and controlling it by my arm (mimicking) using arduino…
servo part is finished now i m looking forward to build an arm,, i wanna ask u what type of wire u have used inside robot’s fingers??
February 1st, 2012 at 10:11 pm
We used bicycle wire.
February 2nd, 2012 at 3:37 pm
thnx bro
February 5th, 2012 at 11:56 pm
Hi,
Nice project! I’m doing an animatronic project about an arm. I liked your project because seems very esay. I have a problem building the arm. Can you help me? what material have you used? Thank you
February 5th, 2012 at 11:59 pm
Hello Laura
This hand is made from stainless steel with rubber (sicaflex) coating. It’s quite heavy so I recommend you to use something lighter.