Author: Dan

Zippy, a DIY SMT PNP (IFKWIM)

Surface Mount Technology (SMT) are the tiny components found on modern PCBs. They’ve grown so small to build a board by hand you need a microscope and the steady hands of a surgeon… or you build yourself a CNC machine with a vacuum on the end that can pick-and-place (PNP) a board for you. I love automation so I think you know where my vote goes.

Richard says he runs 20-30 boards a week on it with 1206 parts. The work areas is ~2×4 feet on a 4×6 foot table, most of which is used for having many rolls of components available. The feeders are his own open hardware design designed in OpenSCAD. (mad respect, yo.) It’s a RAMPS/Mega combination running OpenPNP. I wonder if GcodeCNCDemo would help?

I was having people do manual pick and place before. The error level was fairly high. Even though Zippy needs an operator, and does occasionally drop a part, he *never* puts them on in the wrong spot or backwards.

My favorite part is the camera feedback for picking and nozzle calibration. I’ve never done any camera visualization stuff, so this to me is some dark magic right here.

Read more about the Zippy MK1.

New Product: Robot arm laser cut parts

You’ve got the bearings, you’ve got a 3D printer, all you need is the laser cut parts. Cool! We’re here to help.

The numbers on each part match up with the Bill of Materials in the how-to document.

Order a set of parts now or Find out more about our robot arms.

Makerbiz: Parametric storage bins

I see a lot of cardboard going to recycling because the boxes aren’t very good. I thought “could I reuse them on the spot?”
I’ve designed a parametric picking bin. I hope that my workshop and the local hackspace can use these to save space and stop inventory from wandering off – one of the big challenges of a place with a lot of people is making stuff go back to where it came from.

Try making a box now.

It stacks like a normal box. One end is always open so you can grab stuff from inside without the need to move or open the box. That way the box doesn’t walk away, the lid doesn’t get lost, and there’s no worry about the total box weight.

There’s a lip on the front that should be large enough to fit a label like a UPC code and the item name. It only goes on a shelf one way, so I don’t have to label both ends.

It needs no glue or tape. It can be made from an older box that’s been abused. Hello, IKEA furniture! It can be cut with scissors, scalpel, retractable knife (xacto), or stamped from a template.

Also check it out on Thingiverse.

Also be sure to check out the code for the box generator. It’s a super simple way to generate DXF files that I first used in the Hypocycloid generator. Make all the things parametric!

If this was helpful to you, let me know!

Roboceratops, the robot triceratops

Roboceratops is a 14 degree of freedom animatronic triceratops. It has a custom joystick and a carrying case that looks like it was made by Adam Savage.

Everything after this is Robert in his own words.

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Robot Arm IK Singularities Problem: Can you help?

My goal is to make a 6 degree of freedom robot arm for less, and make it available to everyone.

My first robot arm was 3 degrees of freedom. Given what I’d made before it was pretty straightforward.

My next is an attempt at 5 degrees of freedom.

I’ve got forward kinematics working in software. I tell the shoulder to move and then I can get a point describing the finger tip position and two vectors that describe the finger orientation.

I’m really really stuck on the inverse kinematics. With inverse kinematics I have the position and orientation of the finger tip and I want to find the angle of each joint. I can calculate the position of the finger tip, the wrist, the elbow, the shoulder, and the base. I can even reuse the code from the 3DOF arm to find the angle of the base, the shoulder, and the elbow. The trouble is the angle at each of those positions.

Singlularities

Try this: grab your right index finger with your left hand, then move your right elbow without moving or turning your finger. Each elbow position is a valid answer to the question “how do I move my arm to put the finger here?” A singularity is when there are many answers for the same question, and singularities are trouble for programmers.

Here’s the latest code so you can see for yourself. A picture is worth a thousand words. what’s an interactive simulation worth?

If you have Java you should be able to run this program. fingers crossed! Definitely with eclipse. WASD flies around, QE flies up/down, left click+mouse movement looks around. RF,TG,YH,UJ,IK,OL move the six joints. P switches between forward kinematics (default mode) and inverse kinematics.
You’ll see that in FK the thick model and the thin model always follow each other. In IK the thin model is correct and the thick model is way off. It’s pretty easy make the fat model suddenly flip over or turn unexpectedly – try U and J to make the wrist wave like paint fence:

The software tries to use the bend in the wrist to figure out the twist in the wrist, which doesn’t work the moment the wrist goes totally straight or flips over.

If your code-fu is greater than mine, please show me how it’s done. I’d love to talk to any robotics people out there who might be able to shed some light on this. I feel pretty silly reinventing the wheel. Please help, internet hive mind!