Plexi Bot: Wireless Robotic Arm

 by Mangokid
084 (768x1024).jpg
083 (768x1024).jpg
 Hello all. Recently I have been working on a lot of robotic design and simulation at work. I needed a method of taking my work home with me, and seeing as I can’t carry a large six axis arm home in my briefcase; a solution had to be found. The following set of instructions is my initial design for a small three axis robot that can be used for simulation, small tasks, or just looking cool. This project uses a regular microcontroller, some small stepper motors, and some transistors. This project does not require any advanced equipment or in depth knowledge in robotics, all you need are some basic tools and a bit of work ethic.

The robot featured in the above picture is our final product. It is capable of rotating on three separate axis; rotation about its base, rotation at the base of the first arm, and rotation at the base of the second arm link. There are two levels of this robot, the first has a very basic controller, the second has a wireless controller and some more advanced controls. We will begin with the first design and then once that is finished it can be easily upgraded to the wireless version. The six buttons on the breadboard are use to control which joint is moving and in what direction is it moving. The robot can also be controlled using something called R-code. This code is similar to G-code for CNC, you specify which joint you are moving, the direction, and at what speed it is to move. This code is entered on the computer through a windows application included in these instructions.

So if I have captured your interest (which i hope i have) then I suggest you make every attempt to follow this Instructable and build this robot. Not only will you be able to automate the boring tasks in life but you will also emerge with a greater understanding of micro-Controllers and robotics. 


 a 
 
 
Remove these adsRemove these ads by Signing Up

Step 1: What You Will Need

IMG00366-20110701-1747.jpg
IMG00382-20110701-1806.jpg
IMG00420-20110705-0825.jpg
IMG00411-20110704-1047.jpg
There are several items that you will need to build this robot. All of them can be obtained at either a hardware store or some electronics supplier online.

Materials

3 -Small Gear head Steppers – Robot Shop – 6.99$
2 Square feet of plexi glass – salvaged
Bread board and electrical components - Digikey – 15.00$
16F877A controller - DigiKey – 5.00$
USB RS232 adapter – Ebay – 2.99$ 
Some screws - Anywhere
Netbook – Priceless

Tools

Wire strippers and needle nose pliers (always a must)
P.I.C. Programmer (Cana Kit is excellent)
Scroll saw or something to cut plexi or hard board (even an exacto knife if you are carful)
Wood glue and epoxy
Printer or a pencil and ruler
Drill (Doesn’t have to be a drill press, could be an old hand drill)
 
The details of the circuit work will be outlined in the circuit assembly section. 
sanjevk says: Jul 25, 2012. 8:14 PM
can we use atmega8 mcu instead of pic?b'coz in my region pic mcu's are not readily available...!
ortechltd says: Jul 21, 2012. 10:25 AM
5v stepper motors are not available in my country. how can i use 12v motors??please inform me ASAP
lordl9999 says: Jun 3, 2012. 4:03 PM
would it be complicated (for a know's-nothing-about-robotics (/another instructable would be appreciated)) to apply a third stepper for opening and closing a "claw" at the end of the arm??
lordl9999 in reply to lordl9999Jun 3, 2012. 10:44 AM
*a 4th stpper motor
arick says: Apr 21, 2012. 8:02 PM
How can I make the initial position everytime the system is resetting ?
Or power off, then the hand return to the initial position ?
JordanN5253 says: Dec 19, 2011. 11:40 AM
Very nice looking bot, very interested in making one. There's just one thing I need to ask, you mention it can perform small tasks. What type of tasks can it do? Thanks.
lmateiu says: Nov 8, 2011. 8:20 PM
Hi!
It's nice,but did anyone tried with bluetooth?,because there is a very tyny USB/Bluetooth device for mobile phones and is not expesive...
kevinhorne says: Sep 10, 2011. 11:09 AM
I'm new to field of microelectronics and have been working my way in on various parallel projects. This is an exciting and remarkable project for the site, thank you for posting it.

There were a couple of things I couldn't figure out between your wiring diagram and the images. If you have a moment, I was wondering:

1. Where on the wiring diagram are these two circled items? They look like some sort of capacitor loop, but I can't really tell without it being on the diagram

2. You list out a 1K resistor in the parts list but it looks like there are (7) 3.01K resistors called out on the wiring diagram and they appear to be ?

3. Can you provide a picture of the wiring occurring at the top of the bus runs on the larger breadboard and the precise location of the power feeds - just want to make sure I have things correct before I destroy my chips!

Thanks!
robotarm.jpg
gabrielsan says: Jul 17, 2011. 1:53 PM
Good work. Steepers are much more reliable than hobby servos for this job.
Mangokid (author) in reply to gabrielsanAug 1, 2011. 9:15 AM
Ya they most certianley are. The best part about them is that they dont have the backlash that the hobby servos do. If you look at some similiar bots with servos you will notice that they are extremly jumpy and usually swing all over the place. Also these stepper are geared to 1:64 so each joint has 11'000 diffrent positions over its 180 degree range of motion. I dont think hobby servos are that accurate
tigerbomb8 says: Jul 6, 2011. 10:26 AM
how much can it lift
Mangokid (author) in reply to tigerbomb8Jul 7, 2011. 10:05 AM
it will lift about 100 grams. If you turn up the voltage to 6 or 7 you can lift more but only for a while due to the heat generated in the motor
Pro

Get More Out of Instructables

Already have an Account?

close

PDF Downloads
As a Pro member, you will gain access to download any Instructable in the PDF format. You also have the ability to customize your PDF download.

Upgrade to Pro today!