Mr. Cinderella Fusion

A Pretty Princess

If you’ve seen Mr. Fusion around the space, or at one of the Power Racing Series events this year, you’ve probably wondered what it looked like before we, uh, had our way with it.

It took a bit of digging, but I found an old photo of Mr. Fusion (aka Cinderella) it its original state. Baby blue, pink, and basically a pretty, pretty princess.

Matt W. started the build on this thing, and Chris H took over from there. I ended up doing the body work because I didn’t care for the plain look of it. (We had already removed the Cinderella decal.)

The car was named “Mr. Fusion” due to the vertical motor mount in the back, as a reference to the “Back to the Future” films.

Anyway, this was my attempt to make it look just a little bit more like a DeLorean than a Pontiac. I’ll have a follow-up post detailing more on the body work, and hopefully someone who knows about what’s going on under the hood (and trunk!) can post about that.

PPPRS, We’re coming for you!

PPPRS

We’re just a few weeks out from Maker Faire Kansas City and the first official race of the season for the Power Racing Series.

And for those of you that don’t know, the Power Racing Series (typically abbreviated to “PPPRS”) is a challenge to create a working electric vehicle for less than $500 using open source tools and tech. But we use Power Wheels Cars… yeah, the ones designed for little kids. We rebuild them to hold a full-size adult driver (some of us are even, uh “extra large” as it were) and the add in beefy motors, rechargeable batteries, motor controllers, brakes, sometimes trailer hitches and parachutes, and race ‘em.

We complete against other hackerspaces, like our friends at Pumping Station: One, Sector67, and i3Detroit.

This season we hope to have three cars functional for the races. You may have seen some work on Red Lotus recently. While it was one of our main cars last year, it’s probably the slowest car we have right now, of course speed isn’t everything in the Power Racing Series, and who knows, we may have a few tricks up our collective sleeves by the time the race at Maker Faire Detroit rolls around. ;)

February Electric Car Club

Electric Car Club

Did you know that we’ve got a number of members who have built electric cars? Ben Nelson even runs 300mph.org and has published DVDs and Instructables showing you how to build your own. (Sharing of knowledge is a top priority for our members!)

If you’re interested in electric cars, come on down to Milwaukee Makerspace at 1pm on Sunday, February 10th, 2013 for the first Milwaukee Electric Car Club Meeting at our new location. Got a Tesla, or a Volt, or some DIY/converted vehicle? Bring it! Just want to learn what these electric vehicles are all about? That’s cool too!

The Milwaukee Electric Car Club: Because gasoline is so 20th century.

More Banned Nerdy Derby Cars!

I made the car “Sling Shot” to enter in the recent 2012 Milwaukee “Nerdy Derby.”  During a few initial test runs, my car proved to be more than 10 times faster than the super-clever winning car made by HaveBlue.  Unfortunately, my  car was banned from competition because it was considered a threat to the spectators’ safety!  The consensus was that it had “too much momentum, or energy,” and would hurt someone if it went off the track and hit them.  What does too much energy mean, you ask?  Well, kinetic energy is ½ X Mass X Velocity^2.  Really then, the car was banned because the velocity is too high: It is just too fast!  I’ve already minimized the mass by making the car out of pine, although I could have made it from Balsa Wood, or even entertaining alternate materials such as these.

Anyway, its no fun to think of how to slow Sling Shot down so that its slow enough to safely race, but still fast enough to win.  Instead, I made some new car prototypes that amp up the speed and danger.  If I’m going to be banned in the future, I may as well get banned with style!

Below is a photo of Sling Shot, which traveled the 40′ track length is 0.1 or 0.2 seconds, for an approximate average speed of 300 feet per second, or 200 mph!  Note that the block is anchored to the finish line, thereby stretching the surgical tubing which acts as a spring to propel the car.

I realized that the dominant energy loss mechanism is air resistance – largely because Sling Shot’s wheels don’t even touch the track.  You see, the car doesn’t follow the contour of the track, it just heads directly to the finish line, through mid-air.  I spent some time engineering a more aerodynamic shape to further boost Sling Shot’s speed, searching for a shape that would really slice through the air.  I even consulted a team of highly trained German aeronautical engineer friends, who all approved of my slingshot propelled Henckel Car.  With the improved aerodynamic design, it should easily be faster than the 200mph Sling Shot car shown above.

The other car I built this weekend is also based on Sling Shot, but incorporates some classy chandelier bulbs.  The numerous ‘safety’ lights alert the time keeper of the imminent arrival of the derby car – for safety.

Nerdy Derby Car From The Future

I made the car “Sling Shot” to enter in the 2012 Milwaukee “Nerdy Derby” at Barcamp7 this weekend.  A lot of people were talking about adding motors and fancy electronics, but my car is powered by a spring – a 10 foot length of surgical tubing that is stretched to another block of wood that must be clamped down.  I added wheels, but they aren’t necessary – they don’t actually even touch the track.

Check out what may end up being the only two runs the car has.  Fortunately, JRock captured some video of them.  I’d estimate that the car took 0.1 or 0.2 seconds to travel the 40 foot length of the race track, giving an average speed of 300 feet per second (200 mph!).  The great part about this “sling shot” design is that the car is accelerated by the surgical tubing spring throughout the first 30 feet of the track – until the surgical tubing is completely unstretched.  “Beautiful!”

 

Who wants a Junk Car?

Junk Car

Don’t feel bad for Junk Car… Junk Car does the best it can with the parts it’s been dealt. As we prepare for our Nerdy Derby, we’ve been working on our own cars, but we also want people to bring the cars they’ve made, and we know that some people will show up, and say “Damn! I wish I had a car!” so for those people we’re assembling a box o’ parts. We’ve got some bodies and wheels, and I’m sure the folks at Bucketworks can dig up some crafty materials for decorating the crap out of your crap car. (Remember, there are awards for style as well as speed!)

Spare Parts

And hey, don’t feel bad for Junk Car, it’s just a name. In the hobby robotics world people often use the term “Junk Bot” to describe any robot cobbled together out of spare parts they had lying around, so this is pretty much the same thing.

(And yes, those are laser-cut wheels, and 3D printed wheels you see in the photo.)

Milwaukee’s Nerdy Derby

The Nerdy Derby

One of the things happening at Maker Faire New York this year is the Nerdy Derby, which is described as such:

A no-rules miniature car building and racing competition inspired by the Cub Scouts’ Pinewood Derby. With a larger, more undulating track and no restrictions on the size of the cars or materials participants can use, the Nerdy Derby rewards creativity, cleverness and ingenuity.

We thought this looked like fun and decided to get in on the act and hold our own Nerdy Derby right here in Milwaukee. There’s been a bunch of talk around the space about car design, melting lead, putting the new lathes to work making wheels, and of course, laser cutting cars.

I’ve actually finished my first car, which has a body make entirely of laser cut Baltic Birch plywood, and is filled with sand for weight, which I call “Poundin’ Sand”.

Poundin' Sand

We’ve also got interest from people outside the space, in the greater maker community in Milwaukee. Here’s the amazing progress of Frankie Flood, who is building a replica of a “belly tanker” for his car.

Frankie's Belly Tanker

I can see this thing winning on style points alone! :) (And yes, there are multiple categories you can win, not just “fastest car.”)

There are other cars in progress, and lots of ideas being thrown around the Makerspace about what people are planning to build, so it’s just a matter of time before we start careening down the track. Speaking of the track, we’ve got a regulation Cub Scout track so far, which we may try to modify to match the “official” Nerdy Derby track before the big race.

And when is this “big race” you ask? Well, we’ll probably do a good test race at the space this month, and then if all goes well, we will have the big race at Bucketworks on Saturday night, October 6th, 2012 during BarCampMilwaukee.

And we want you to join us! All you have to do is build a car, and show up. I know we said “no-rules” but we do have two semi-rules: don’t damage the track,and don’t make anything so dangerous it could easily injure someone. Besides that though…. anything goes! Don’t have all the parts you need to build a car? We’ll do our best to provide some parts at the race so you can make one on the spot.

See you at the races!

Red Lotus Build [Time Lapse Video]

This is a time lapse video of “Red Lotus” the Power Wheels race car that Milwaukee Makerspace built for the 2012 Power Racing Series. Tom Gr. did almost all the work (with some help!) His original plan was to do the whole build in one weekend… It took a little longer, but not much.

We’re looking forward to the 2013 season and have already started planning. I’m going to say this right now: Sector67 and i3Detroit, we’re coming for you!

Rotary Encoder – built into motor for Electric Car

My electric Dodge neon uses an AC motor and an industrial motor controller.  I upgraded from m 1984 motor controller to one less than 25 years old (actually less than 5.)

The new controller does much more than the old one and has the ability to do some fancy tricks.  At the moment I am running it in “sense vector” mode.  The controller senses the position of the armature by monitoring the current in the field coils.  This works great…   as long as the motor is spinning.  From a stop it tends to get out of sync, but there is a cure!

The controller can use a quaderature encoder so the encoder can read the position of the armature at any speed.

To add an encoder to the motor I decided to try a chip amde by Austrial Microsystem AS5040.  This chip senses a magnet near the chip and calculates the position of the magnet and can generate multiple output:  PWM, binary via I2C, and quadurature!

I bought a few of the chips and built a surface mount board to hold the chip and a few LEDs to display the output.  The first two version had a few problems but the 3rd time was the charm.

 

 

Thanks to Royce for working out the process for surface mount PCBs.

 

The final version had to be small enough to fit in a depression in the end of the motor cap.  The sensor centered and the whole board insulated (clear enamel)  since this is a grease pocket

for the rear motor bearing.

 

 

 

 

The magnet is mounted to a bolt that is threaded into a tapped hole in the back end of the armature.  It took a while to the position right (it needs to be within a few millimeters of the sensor) hence the nuts and washers.

 

The cable is brought out of the motor through a small threaded hole (it was an alternate location for the grease fitting.)  The hole is filled with epoxy and the wires go to a DB9 connector.   I built a small test board that shows the quadurature signals (4 round LEDs) and the status outputs from the chip (the two rectangular LEDs)

 

 

 

 

 

The motor controller puts out 15V to power an encoder and wants A and B as well as inverted A and B signals.  The circuit includes some NPN transistors along with a voltage regulator and a few capacitors to tie it all together.  I put the schematic for both the sensor and test board on one schematic so I could make both boards at the same time.

I installed it in the car today, but still need to put a few more parts together to run it.

 

 

 

DOH!

It doesn’t work!

Ok, so the electronics work fine, it talks to the controller.

But it tops out at 256 pulses per revolution and the controller needs 1024.  It was a minor confusion between terminology.  The sensor detects 1024 positions, but to generate quaderature it uses 4 positions per pulse output.

Back to the drawing board.

 

I picked up a commercial shaft encoder on ebay for 50 that outputs 1024 PPR but it only works at 5V, so I’ll need a level shifter board and connector adapter.

Oh, yea, and I need to put the motor again, take out the old encoder, bring a shaft extension through the back grease pocket, add a grease seal and couple it to the encoder.