Let's Make Robots!

UPDATED Acrylic Arm

Robot arm things

Hey look, a new description!  \/

I started this robot over a year ago. I happened to have just recieved a box of parts from a copy machine and was astounded by all the goodies. What stood out to me the most were those 2 wonderful steppers down below. My first thought was "CNC machine ya!", but I decided I didn't need ones that big for a desktop CNC machine. A few days later I thought about having a robotic arm mounted on my desk. So I went and looked through my copy machine parts box and found that bracket\motor assembly. As I marveled at the beautifully large gear I realized this would make a great base. The large gear would give a slow enough speed and high torque. Then after looking up the datsheets for those two motors I realized they would be great shoulder and elbow motors.

The next day I made a very rough list of parts and went to Lowes. I bought some random bolts, nuts, washers & a sheet of acrylic. After I got home I made a couple paper templates and traced them on to the acrylic. I am not the kind of person who makes a plan for my robots. I just kind of ad-lib it. Anywhositnow, the next day I cut all the pieces, drilled them, and epoxyed them. Then the day after that when the epoxy dried I mounted the motors and left it...for...a year. Yes I know, who abandons a robot when it is so close to life. It actually was almost complete except for a wrist and gripper.

About a week ago I came across this website and decided to post my robots. That is when I noticed my robotic arm sitting sadly on the back of my desk. Thanks to this website, the arm now has a wrist and gripper! I had asked in the comments below for some gripper ideas and I came up with this: servo wrist, claws synchronized by gears, Flexinol (an SMA wire like Muscle wire) actuated gripper. Dowm at the bottom you can see the gripper design.

Now I am working on the controls. I have planned to control it by a custom made Visual Basic program, but I know very little about interfacing a program to a parallel port. YES I WANT TO USE THE PARALLEL PORT. I like the simplicity of a parallel port. So if you could suggest how to use the parallel port in Visual Basic, I would mucha appreciate it. Enjoy.

a view of the base

I couldn't have made the belt on the shoulder motor any tighter. I have tried to make the belt slip and was very pleased to find I couldn't.

a view down the upper arm to the elbow motor

The picture above shows the elbow joint and the belt that runs from it to the elbow motor at the shoulder. You can't really see it, but near the elbow is a tensioning wheel.

the base

above is the rotation motor. The gears on the shoulder and elbow motors just happened to fit the belts perfect.

the claw

 

This is the gripper I made. The two fingers are epoxyed to the gears and they will be actuated by Flexinol. The screw on the left is for a spring to return the gripper to the open position.

 

 

 

 

 

 

 

  

 

 

Claw_008.jpg

 

This is the servo on the wrist. You can tell I like epxy putty. The epoxy putty was placed on the gripper base and the screws inserted while it cured. This ensured a perfect thread when I attached the servo. The sevo is attached onto one side of the arm by a large serbvo wheel. The other side has a bolt epoxyed to the gripper base.

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Cool robot arm!

good job

heres a tip old bike brake assembelies work awsome as grippers

Modeling a gripper, this can be done many different ways.

  Some use the "generic wire plires with a draw idea".this makes a good pincer but Personaly, I prefer to model after what is called "paralell pliers" which is a jewelers tool it uses two flatt bars with a crossing fulcrum "imagine a sissor jack lowering a car" with the jack attached to both the car and ground as the gripper ends. these type pliers are used in jewelery because the "pressure is evenly spreadout" and don't scar the work.

 You can google "paralell pliers" for a picture, this will easily accept a pressure sensor and a proximity sensor to aid in finding and not crushing objects too. 

 you may even take a look at my primitive mandable on my bugbot1 listed on the robots intro forum though it is modeled after a paralell it uses a draw instead of a crossing fulcrum.

iamdenteddisk@yahoo.com

 

 

I thought about that, but I decided to use a regular old single fulcrum type on my first arm. Thanks for the input though, I didn't know there were pliers like that. I think I'll look into it. 

The world's best motto: When all else fails, use a bigger hammer.

woops, double post 

The world's best motto: When all else fails, use a bigger hammer.

I thought about that, but I decided to use a regular old single fulcrum type on my first arm. Thanks for the input though, I didn't know there were pliers like that. I think I'll look into it. 

The world's best motto: When all else fails, use a bigger hammer.

Hi,

Very cool! I am just learning about all this... but one idea I had was using salad tongs. The other night one of my little guys at dinner was serving his salad and pretending he was a robot with the tongs. They are light metal, that you could cut down and then add some pads to. Sorry if that is a dumb idea. Just thought it might be something inexpensive that you could go off of.

 Shawn 

Sounds good to me. 

The world's best motto: When all else fails, use a bigger hammer.

My "local" Ikea sells those tongs with silicon pads already in place. They are used to turn over the meat in the frying pan. For example...

32419_PE122379_S3.jpg
KONCIS 

Clear stuff adds to a project, good to see the parts working. I knew a guy here that cut his gripper out of a sheet of plastic, and cut the plastic at the pivot in such a way to form a rough gear. He used a CNC setup to cut the gripper with gear, and attached a servo to one side, as the other side turned with it.

Another gripper idea is to have spring loaded fingers, that are held out, then pull them towards each other with fishing line, threaded down the middle to a reeling in motor.