Extendo Hand

24,734

102

57

Published

Introduction: Extendo Hand



Sometimes wish I had an extendo hand to help me reach things that are just a little too far away. For instance, picking plums off of the trees around here in Santa Clara, they are usually just about 12 inches too far away for me.

This is totally ridiculous, I know, but here it is...





here's my boyfriend Greg picking plums with it:




Step 1: Stuff You Need

a wrist brace (you can find these at Safeway made by Ace bandages)
5 spring type door stoppers
some wood and some screws
5 large washers with holes big enough to fit your fingers through
some string
some eyelet screws to guide the string through
cable ties

Step 2: Attach the Fingers

attach the door stoppers to a small chunk of wood which will act sort of like the palm of the hand.

I tried a couple of different directions for the thumb, but straight up at 90 degrees seemed to be the best idea.



Step 3: Attach the Tendons

first tie the strings to the tip of the door stops underneath the rubber end caps.

then secure the string to the "knuckle" part of the door stopper with cable ties.

attach the eyelet screws to the wooden palm and guide the strings through them.

Step 4: Attach the Hand to the Arm Bone

attach the palm to a long stick of wood to be the arm with screws.

attach the wrist guard to the wood at the other end with screws also.

Step 5: Adjust the String Length

put your hand inside the wrist guard and tighten it down with the velcro straps. You may need to add some velcro to the backside of the wood for it to grab onto.

carefully connect the large washers to the tendon strings and align them so the inside holes just reach the tips of your fingers.

Step 6: Now Go and Grab Some Stuff!

We tried this out on the trees outside and it kind of works for reaching up really high to get plums.

The fingers aren't too strong though, they keep shifting to the sides a little. And it needs some padding under the knuckles and on the finger rings if you're going to use it a lot.



Instructables and RoboGames Robot Contest

Second Prize in the
Instructables and RoboGames Robot Contest

Share

    Recommendations

    • Oil Contest

      Oil Contest
    • Planter Challenge

      Planter Challenge
    • Casting Contest

      Casting Contest
    user

    We have a be nice policy.
    Please be positive and constructive.

    Tips

    Questions

    57 Comments

    I will post some pictures soon, I made one that didnt quite work but I have a great Idea to modify it a little bit from your design.

    cool, maybe share some pictures when you're done?

    I like these videos they are really fun, makes me want one too.

    user

    Awesome!, it grabs just like a real hand :D! wraps around the item.

    Now I can go dumpster-Diving in style! At least it won't cost me $29.95! Thanx! I'd sure as hell like to try it out! Hard Tymes

    I'll spoil the mood by saying 'stick to XP'

    Neato! I've been sort of planning on doing something like this myself (probably with a slightly larger model of my own hand), but with actual joints on each of the fingers + thumb. It'll be really complicated, but I'm thinking of using a system similar to the cables on bicycle brakes for flexing.

    8 replies

    Yes, my first thought was to use something called "aircraft cable" which is a very strong and thin stranded metal cable. I got some from OSH but then when I went to cut it, none of my wire cutters or other tools could make a pass through it. OSH was out of cable cutters, so I just went with string which worked out well enough.

    OSH? Isn't that Occupational Saftey Hazard? (Im not being stupid, it's a serious question)

    I think you're referring to OHS, Occupational Health and Safety, I don't think the hazards have an acronym, although yours is reasonable enough.

    The reason I said OSH is because that's what the helth and saftey thingy-ma-bob of the government is called where I'm from (I could be confused though)

    Oh, sorry, around here it stands for "Orchard Supply Hardware"

    you should look up adam's bionic hand from myth busters..... you might find that interesting....

    Would you happen to have a Youtube link, by chance? I can't find anything, but given that it's Mythbusters I'm guessing that it's just a *bit* more expensive than I could reasonably afford :P

    In your next version or possibly as a revision to this version, if you plan to do either, you could add a simple pulley to the base to make the grip stronger with less effort required by the user. Since it's such a long base many pulleys could be used, although after two it might be a little ridiculous since you'd need your other arm to pull the strings far enough to fully contract the fingers. Your design is great, and the only thing I would do differently following this instructable, would be adding a string for the thumb, and some more wood at the base to allow your thumb to control it separately from the hands, allowing you to do things like shake hands and operate buttons.

    user

    The twangy doorstops! I haven't seen those in ages...

    This is a really cool idea, if you wanted some next-level freakyness you could put a glove on the hand- it might make fruit-picking better (less bruising) and would look distinctly weird. Then sew extensions onto your sleeves and frighten small children with it :D

    hehehehe

    2 replies

    I was trying to think of some sort of rubbery thing to put on the fingers to give them more gripping power. Like maybe those rubber fingers that they have at the office supply store that people used to use who handle a lot of paper.

    or some rounded off hot melt glue.....