This is a Derivative of the original Yazzo PolyBot by WilliamAAdams. I found the original design to be something I wanted to build and test with immediately. So I found some things I wanted to do differently and wanted other people to experiment with this awesome robot.
UPDATE: The Female and Male Clevis Elbows I had uploaded here are the wrong size. I no longer have the proper size on my computer. Please follow these links to get them:
On the original Polybot the files were spread around Thingiverse and were very hard to find, I have consolidated them into one spot.
I have also changed the threaded rod connectors of the Tetrahedron support structure. These new ones should be much easier to print and will print without support. They should also be much sturdier.
I have also changed the servo brackets to make them much easier to mount the servos. You no longer have to take apart your servos and struggle with getting them back together in order to mount them. The servos also sit out further off the platform. With the original design, the servos sat too far in on the platform making it impossible to get a good range of motion for the servo arms.
One of the negatives of these new designs is the need for fasteners. The original PolyBot was designed to use as few fasteners as possible. This one can be edited to make the holes smaller on the printed parts for the threaded rod to fit snugly into without the use of nuts. I prefer to use nuts because it makes assembly so much easier. Nuts are pretty inexpensive too and you are probably going to be in the hardware store anyway for the threaded rod.
Currently, I am using standard Medium Hobby Servos to move the arms. For now they work really well and easily move the lightweight arms of this bot.
As for the micro-controller, I am using a Picaxe 28X/40X. But you can use whatever you like.
If you find this bot to be interesting, I seriously recommend printing and building it. It is pretty cheap to build and doesn't take much time. It is a lot of fun to mess around with. As for improvements, I already have a bunch of ideas in mind. And I know WilliamAAdams is working on improvements for the original Cranberry Yazzo Polybot, hopefully he will release something soon!
Here is a video of it moving... I should have gotten it to do something more interesting. But I have to go to work in the morning and I spent the night preparing the files and doing this write-up. Kind of lame, more and better video soon! I promise!
Another update... I couldn't leave it for the night with just that crappy first video. So I programmed some numbers that might make the bot look like it is moving semi-coherently.
So here is a better video of Delta Robot Movement:
Print out the following:
12 Clevis Elbows - Male - Follow the Download link in the description!
12 Clevis Elbows - Female - Follow the Download link in the description!
1 Tritool Effector
3 Keyed Swivel Mounts
3 Servo Horn Arms
3 Servo Brackets
3 Tetrahedron Base pieces
1 Tetrahedron Top Piece
3 Tetrahedron Middle Pieces
Note: This design was meant to use 8mm threaded rod. I used 5/16 inch rod because it is difficult for me to get metric threaded rod. The design is such that either 8mm or 5/16th inch rod will both work great.
Build the Tetrahedron (three sided pyramid), I used precut 2' long 5/16 threaded rod that I bought from Home Depot. I purchased 6 2' pieces and one 3 foot piece. You can use whatever size you want, the design is scalable. Of course the limitation would be the diameter of the rod, you probably won't want to make the segments TOO long, because it will be unstable. You will also need around 42 5/16" nuts. The Tetrahedron Connectors are designed so the rod goes through the connector and pokes out the other side a little further than the width of a nut. A nut is supposed to be placed on each side of the connector for each rod piece that intersects with a connector (look at the pictures if that isn't clear). Don't forget the middle connectors will need nuts of their own threaded on. The length of the edges of the triangle that makes up the middle platform (where the servos sit) is 9 inches. This is an equilateral triangle too, so that means the middle platform sits 9 inches down from the top of the tetrahedron. Just cut the 3' foot pieces so you get 3 x 9" pieces.
Next you can put a piece of plywood or something on the middle platform. I used foam core. This piece doesn't need to be super sturdy in the bots current state. I have been running it fine with foam core. The piece of foam core I used is secured to the threaded rod with zip ties.
Next you can build the actual moving part of the robot. I used 5/16" wooden dowels around 7 inches long. You will need 6 of them. Connect the female clevis elbows to the ends of both sides of each dowel. Then you can attach the male clevis elbows with some 3mm nuts and bolts to the female clevis elbows (Sorry I can't stick to one unit of measurement, hardware stores in the USA don't carry Metric threaded rod). Now you are going to need some short 5/16" dowels to link the male elbows to each other and the keyed swivel mount and servo horn linkage. You can now attach the tri-tool to the keyed swivel mount. Don't attach the servo horn arm to the servos yet.
Now just mount your servos to your servo brackets. With this new servo bracket design, you will need to bolt them in too. I used more 3mm nuts and bolts to do this. Trust me, its alot easier they taking the servo apart and trying to jam it through the old servo mount. A lot can go wrong when you do that. I then secured my servo mounts to the platform using zip ties through the closed off rectangle of the servo bracket. I only used one zip tie on each and they seem to hold fine for now.
You probably want to hook up your micro-controller before you attach your servo arms to the servos. That way you can make sure they are all at the right positions (or you could manually move the servo to the maximum or minimum of the range with your hands). Now once you have the angle right attach the servo arms.
And now you should have a Delta Robot Test Platform!