News – Page 28 – Marginally Clever Robots

Why no one makes hypocycloid gearboxes

2015-05-19 Dan

Gearboxes can turn a weak fast motor and you need

When you buy a Marginally Clever robot kit, you don’t just get an awesome robot. You push the boundaries of science and engineering by funding my research. It’s a bit like I’m trying to run a personal Skunkworks.

You’ve heard me talk often on this site about my desire to build robot arms for less and make them for everyone. I need a gearbox so I can build the arms with affordable 3d printer electronics and hardware. Gearboxes transform weak but fast motors into slow but strong motors. Not every gearbox is right for robots. A good candidate is a hypocycloid, cousin of the harmonic gearbox.

these video’s aren’t mine. They are here to illustrate the concept.

I spent $3000 on a prototype that doesn’t work. In spite of the incredible tolerances and the top quality machining, we couldn’t get the gearbox to run without binding or jamming. More on that at the link, as well as details on my progress with the robot arm.

On the bright side, I can share my progress and save each of you a small fortune. Plus I haven’t given up. At a recent Bring-a-hack dinner after the 2015 Bay Area Maker Faire I got a number of great tips and suggestions about how to try again. They ranged everywhere from “run a kickstarter to fund more development” to “add more lasers”.

Do you have any ideas why the gearbox doesn’t work? Have you tried to make a hypocycloid or a zero-backlash gearbox? Comment below.

For more up-to-the-minute news about stuff I’m making, follow me on instagram.

Building your own solenoid engine

2015-03-20 Dan

I’m leaving for a week in Mexico starting tomorrow morning, so I don’t have a lot of time to write a blog post today.
Instead, here’s a random Internet Find of the Week: How to build your own solenoid engine.

News Tutorials

Maker Tip: Labels on all your Custom Pieces

2015-02-27 Dan

I’m a big fan of Kaizen, the process of continual refinement. Opportunity is everywhere if you’re looking for it. Sometimes it’s obvious like “hey man, I think you should put a link to X on page Y of your tutorial!” …Ok! Sometimes it’s more subtle, like when a customer on the phone tries to describe a part for which they have no name.

On the good suggestion of Sarah Petkus of RobotArmy I’ve started putting part numbers right on all my laser cut pieces. Now I realize it was a hole in my inventory control system. I had a separate inventory number for every item in the store, but the laser cut parts were clumped together as “laser cut parts for kit X”. Now that I have separate part numbers I can… (more…)

News

Yale’s Open Hand Project

2015-02-25 Dan

If you know me, you know I’ve been obsessed with robot arms for a long time. People ask me “what will you put for a hand?” and I used to say “Who cares? It could be any tool you like.” Well, now I have a better answer.

Yale’s Open Hand Project aims to make an open source robot hand that anyone can download and build. It even comes with adapters for several popular robots already on the market.

I think my favorite part is their Hybrid Deposition Manufacturing (HDM) technique: The finger bones come out of the printer with built in pockets into which you pour a urethane solution. When the urethane hardens to a rubber consistency, the pockets break open and you’re left with a 2-material, super flexible shape. Genius!

News Tutorials

Little Big Planet Sackboy faces with the Arduino Starter Kit

2015-02-18 Dan

Today, we’re going to build faces using LEDs and a joystick. Previously, we’ve wired up LEDs and learned how to control individual lights, how to draw pictures, and how to use a joystick. Today, we’re gonna put them all together to make a set of emotions based on the direction we push the joystick. Again, we’ve got the debounce, so the emotion will stay on our screen until we push the stick in a new direction.

(more…)