Saturday, October 18, 2014

MIT Mini Maker Faire 2014

I made a quick trip back to Boston/Cambridge for the first ever MIT Mini Maker Faire. Recap and pictures below, but first here is some video from the event:

As expected from an MIT Maker Faire, there were lots of electric go-karts, Tesla coils, 3D printers, robots, and... scooter...things.
To this I contributed a set of long-time Maker Faire veteran projects (Pneu Scooter, 4pcb, Twitch) and a couple of new things (Talon v2 multirotor, Grasshopper3 Camera Rig). I always like to bring enough projects that if some don't work or can't be demonstrated, I have plenty of back-ups. Fixing stuff on the spot isn't really possible when you have a constant stream of visitors. But I've been to a number of Maker Faires and decided the maximum number of projects I can keep track of is five. Especially since this time I had to be completely mobile, as in airline mobile.

Arriving at the venue, MIT's North Court, luggage in the foreground, MIT Stata Center in the background.
The travel requirement meant that, unfortunately, tinyKart transport was out. (Although it is theoretically feasible to transport it for free via airline except for the battery and the seat...) But Pneu Scooter is eminently flyable and in fact has been all over the world in checked baggage already. It collapses to about 30" long and weighs 18lbs. The battery is well within TSA travel limits for rechargeable lithium ion batteries installed in a device. Oh, and Twitch fits right between the deck and the handlebar:

It was definitely designed that way...
Pneu Scooter and Twitch are really all I should ever bring to Maker Faires. They are low-maintenance and very reliable; both have survived years of abuse. In fact, Pneu Scooter is almost four year old now...still running the original motor and A123 battery pack, and still has a decent five-mile range. (I range-tested it before I left.) It's been through a number of motor controllers and wheels though. Because the tires are tiny, it's always been a pain in the ass accessing the Schrader valves with normal bike pumps. Turns out it just took five minutes of Amazon Googling (Is that a thing?) to solve that problem:

Right-angle Schrader check valve. Why Have I not had this forever?
Pneu Scooter survived the rainy Faire with no issues - it's been through much worse. I participated in the small EV race featuring 2- and 3-wheel vehicles. Unfortunately I didn't get any video of it, but Pneu Scooter came in third or something...I wasn't keeping track and nobody else was either. Mostly I was occupied by trying to avoid being on the outside of the drift trike:

Yes, those red wheels are casters...
But if I had to pick one project that I could pretty much singly count on for Maker Faire duty, it's Twitch.

Despite the plastic Vex wheels, Twitch has been pretty durable over the years. I had planned to spend a few days rebuilding it since I thought one of the motors was dead, but when I took it off the shelf to inspect, it was all working fine. In fact, the only holdup for getting it Faire-ready was that the Direct Input drivers I have been using since .NET 1.0 to read in Twitch's USB gamepad controller are no longer supported by Windows 7/8. Yes, Twitch outlasted a Microsoft product lifecycle... Anyway, after much panic, I found a great free library called SlimDX that offers an API very similar to the old Managed Direct X library, so I was back in action.

Basically, Twitch is an infinite source of entertainment. I spent a lot of the Faire just driving it around the crowd from afar and watching people wonder if it's autonomous... I would also drive it really slowly in one orientation, wait for a little kid to attempt to step on it (they always do), and then change it to the other orientation and dart off sideways. And then there is just the normal drifting and driving that is unlike any other robot most people have seen. I found an actual use for the linkage drive too - when it would get stuck with two wheels on pavement and two wheels on grass, it was very easy to just rotate the wheels 90º and get back on the walkway. Seattle drivers need this feature for when it snows...

Twitch is definitely my favorite robot. Every time I take it out, it gets more fun to drive. I have 75% of the parts I need to make a second, more formidable version... This Maker Faire was enough to convince me that it needs to be finished.

4pcb was a bit of a dud. I don't know if my standards for flying machines have just gotten higher or if it always flew as bad as it did during my pre-Faire flight test. It still suffers from a really, really bad structural resonance that kills the efficiency and messes with the gyros.

It was one of the first, or maybe the first PCB quadrotor with brushless motor drivers. But the Toshiba TB6588FG drivers are limited in what they can do, as is the Arduino Pro Mini that runs the flight control. Basically, it's time for a v2 that leverages some new technology and also improves the mechanical design - maybe going to 5" props as well. We'll see...

And unfortunately, because of the rain and crowds, I didn't get to do any aerial video with my new Talon copter. But it looks good and works quite nicely, for a ~$300 all-up build. (Not including the GoPro.) Here's some video I shot with my dad in North Carolina that I had queued up to show people at the Faire.

Talon v2, son of Kramnikopter.
Electric linkage drive scooter my Kickstarter plz.
The last thing I brought for the Faire was my Grasshopper 3 camera setup with the custom recording software I've been working on for the Microsoft Surface. With this and the Edgerton Center's new MōVI M5, I got to do a bit of high speed go-kart filming and other Maker Faire documentation. The videos above were all created with this setup.

I had a stand, but this seemed easier at the time...
As a mobile, stabilized, medium-speed camera (150fps @ 1080p), it really works quite nicely. I know the iPhone 6+ now has slow-mo and O.I.S., but it's way more fun to play with gimbals and raw 350MB/s HD over USB3. Of course it meant I had 200GB of raw video to go through by the end of the Faire. I did all of the video editing in Lightworks using a JPEG timeline. (Each frame is a JPEG in a folder...somehow it manages to handle this without rendering.)

And that's pretty much it. It was much like other Maker Faires I've been to: lots of people asking questions with varying degrees of incisiveness ("Is that a drone?"), crazy old guys who come out right before the Faire ends to talk to you about their invention, and little kids trying to ride or touch things that they shouldn't be trying to ride or touch while their parents encourage them. Although I did get one or two very insightful kids who came by on their own and asked the most relevant questions, which gives me hope for the future. It was great to return to Cambridge and see everyone's cool new projects as well.

My MIT Maker Faire 2014 fleet by the numbers:
Projects: 5
Total Weight: ~75lbs
Total Number of Wheels: 6 (not including omniwheel rollers)
Total Number of Props: 8
Total Number of Motors: 18 (not including servos), 1 of my own design
Total Number of Motor Controllers: 18 (duh...), 16 of my own design!
Total Number of Cameras: 2

And here are some more pictures from the Faire:

I'm not sure what this is.
Dane's segboard, Flying Nimbus, which I got to ride. It actually has recycle Segstick parts!
Good old MITERS, where you can't tell where the shelves end and the floor begins!
Ed Moviing. I finally figured out a good way to power wireless HD transmitters...can you see?
A small portion of the EVs, lining up for a picture or a race or something.
Of course there were Tesla coils.
Flying out of Boston after the Faire, got a great Sunday morning view.


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