Project MagneTag

MagneTag is a project I started about four years ago, when I first joined Milwaukee Makerspace.  My goal was to create an electronic scoring system for physical tag games.  As a paintball enthusiast I really enjoy the action and tactical nature of the sport.  I was looking for a method that wasn’t messy or painful and 100% reliable .

In order to accomplish this goal, I employed the mystical power of magnets. It’s a scientific fact that magnets are awesome.  I knew that the invisible forces created by magnets could be used to create electrical signals, the technology has been around since Maxwell wrote down his famous equations of electromagnetism.  So I set  out to build a wearable system that could electronically detect magnets, be they in some projectile, or embedded in an a foam gladiator weapon, or whatever.

To an experienced engineer, this might not seem like a huge challenge, but when I embarked on this project I could barely operate an Arduino. I didn’t really understand what I was getting myself into.  Now, I have an above average understanding of the principles of electromagnetism because I have a two degrees in physics, but in trying to make my idea a reality, I now understand that theory does not get you very far on its own.   Making things is freakin’ hard, and you have fail many times before you begin to really understand how much you don’t know.  When it comes to making, there is no substitute for experience.  And I learned this the hard way, over and over again.  Persistence removes resistance.  In the end I succeeded and created something even better than I had imagined.

Milwaukee Makerspace is an awesome place. I’ve had so much help from some brilliant members, and the tools we have access to are invaluable.  I even met my business partner Jason at MMS.  Without this place, MagneTag would have just been a cool idea I had one time.  It never would have become a real thing.

This week marks a significant milestone in the history of our project: we are launching MagneTag on Kickstarter!  We are going to put our game out there into the world and see if people really like it.  Check out the launch video below, as well as a behind the scenes video, most of which takes place at Milwaukee Makerspace!

Also come check us out at Maker Faire Milwaukee! It’s gonna be a blast!

Kickstarter launches Friday Aug 7.

 

Chocolate Cooling System Almost Ready For Testing

Chocolate printer progress continues.  This week was devoted to the print cooling system.  The chocolate will come out the extruder nozzle in a semi-molten state.  It needs to solidify by the time the next layer of chocolate gets deposited on it, and I’d prefer it doesn’t drip or sag, so it needs to be chilled right after extrusion.  The current plan is to blow chilled air over the chocolate just after it leaves the extruder.   The chilled air will come from a foam insulated box containing a block of dry ice.  There will be a blower pushing air into the box and a hose delivering the chilled air/CO2 to the print.

A couple weeks ago I got a blower from American Science and Surplus and this week I got it running by using a model airplane ESC and servo tester to drive its brushless DC motor.  It appears to be capable of blowing much more air than I’ll need.  There are many unknowns yet to test.  How much chilled air/CO2 will it take to solidify the chocolate after it leaves the extruder?  How long will a block of dry ice last when used this way?  Will ice build-up inside the chiller box adversely affect its performance?

I designed and printed three parts for this system- a mount to attach the blower to a foam box up to 1.5″ thick, a hose coupler to allow delivery of the chilled air/CO2 to the print, and a hole saw to cut holes to fit the other two parts.   The printed parts fit as if they were designed for the job!

3D printed hole saw

3D printed hole saw

Hose connected to hose coupler

Hose connected to hose coupler

Hose coupler parts

Hose coupler parts

Blower mount for air chiller box

Blower mount for air chiller box

Noah Way!

Noah Way!

A few of us worked on a car for The Power Racing Series and somehow we got it done at 3:15am on Thursday night after about a week of intensive nights cutting wood, and trying to weld metal, and scrounging for batteries. We then took it to Maker Faire Detroit and raced it.

The car is modeled after Noah’s Ark, supposedly dimensionally accurate, scaled down, of course. It runs at 24 volts and uses one 250 watt hub motor meant for a bicycle. It was not fast. It drives like a boat, maybe because it is one.

We didn’t break down until the last few minutes of the Endurance Race when we popped a tire, so we just kept going on the rim. (Our qualifying lap was 40.40 seconds. Also our car is #40. Amazing!)

We built this in about a week, and made a lot of compromises to get it done on time. Originally we were going to use two 250 watt hub motors for the rear wheels, but… compromises.

The good news is you can spin around in a super-tight radius by turning the wheel 90 degrees and then going full throttle. The bad news is, you might puke afterwards.

Anyway, we’d love to see more people build cars for The Power Racing Series event that will be happening at Maker Faire Milwaukee. If you start now, you’ve got 60 days, and since we built this in about 6 days (and rested on the 7th) it should be totally doable.

Remember, you don’t have to be fast if you’re awesome. You do need to go, and stop, and not take it too seriously. If you can do those things, we’ll see you at the races!

1MHz DC-DC Converter Test

dcdc1mhzThis week I tried out a new DC-DC converter, the RT8293BHGSP, for my singing pumpkin controller. The issue I had with the old converter was that it was pretty expensive to get a 100uH coil that was rated for 4 or 5 amps. The most recent spin of the board only has about a 1.5 amp coil on it. This new converter runs at a little over 1Mhz as opposed to ~300kHz for the old converter. As such it can use a much lower value coil (10uH) that can be obtained in the 4 to 5 amp range for a reasonable price and with a reasonable package size.

This tester board seemed to work pretty well. It got plenty warm pushing around 2 amps, so it may need a heat sink. Still I’m pleased to have a solution that lets me get all the way up to the 3 amp limit of the converter.

 

First Ever Test of the 3.5 Liter Syringe Extruder

My last post showed how I made a plunger for a 3.5 liter syringe.  Today’s post is the results of the first ever test of that syringe assembly including the plunger.  The goal of the test was to determine if the syringe pusher would be able to push very thick, viscous paste (sort of like melted chocolate) out of the 1/4″ syringe nozzle.  It was also a test of the ability of the previously made silicone plunger to maintain a seal even against whatever pressure develops inside the syringe as it is pushing.

I mixed about 1 liter of extra thick pancake batter to a consistency that I thought would be much thicker than molten chocolate (pancake batter is much cheaper than chocolate) and shoveled it into the syringe, then bolted on the pusher and hooked it up to a power supply:

Looking back, I probably should have loaded the syringe from the other end.

Syringe loaded with super thick pancake batter.

Syringe loaded with super thick pancake batter.

 

 

 

 

 

 

 

 

 

 

 

Here’s the actual test.  It gets especially interesting about 1 minute in:

The syringe continued drooling after power was removed due to air that was trapped inside the syringe.  As the plunger pushed, the air was compressed.  When the motor stopped the compressed air continued to push out the batter.  I will have to be careful to eliminate air bubbles in the material when it comes time to use this in a printer.

It only took a couple minutes to clean out the syringe after the test was done.

The pusher did its job much better than expected, and the plunger held up just fine, too.  I feel confident that this device will be able to extrude chocolate.   Now the real work begins…

Making a Plunger for a Chocolate Syringe

My latest project is a 3D printer that will produce chocolate objects.  Like many other chocolate printers, it will include a syringe to dispense the chocolate.  Unlike those other printers, the syringe in my printer will have 3.5 liter capacity to enable printing large objects.

The syringe is made from PVC pipe using mostly standard fittings.  One piece that wasn’t standard was the plunger that fits inside the syringe tube and pushes on the chocolate contained therein.  I had to design and fabricate the plunger.  PVC pipe isn’t perfectly smooth or perfectly round inside, so I needed something compliant enough to ride out the pipe’s bumps and constrictions while maintaining a seal.  The seal needed to be tough, yet safe for use with food because it will be in contact with the chocolate inside the syringe.  I found some food-grade silicone casting material and ordered it.

While waiting for the silicone to arrive, I designed a 3D printable core for the plunger and a mold and jig.  The core fits on the end of a linear actuator that will provide the push.  The jig centered the core a few mm above the bottom of the mold.  The mold was tapered and the widest part -the bottom- was a few mm larger diameter than the pipe, and several mm larger diameter than the core.  The silicone envelops the core and is locked in place by holes that connect top and bottom side of the core.  The plunger squeeze-fits into the pipe to maintain the seal against the uneven inner surface of the pipe.

Mold, jig, and core for syringe plunger

Mold, jig, and core for syringe plunger

Mold, jig, and core for syringe showing core inserted into jig.

Mold, jig, and core for syringe showing core inserted into jig.

 

 

 

 

 

 

 

 

 

Mold, jig, and core assembled for silicone over-molding.

Mold, jig, and core assembled for silicone over-molding.

I measured and mixed the silicone, coated the core with it and then set the core and jig in/on the mold and let it cure for 24 hours.  Then I removed the jig and broke the now silicone covered core out of the mold.  Result: a perfect, tight fit inside the syringe tube.

Core in mold with silicone.

Core in mold with silicone.

 

 

 

 

 

 

 

 

 

 

Finished plunger removed from the mold.

Finished plunger removed from the mold.  The mold had to be broken off by design.

 

 

 

 

 

 

 

 

 

 

 

Plunger mounted on linear actuator.

Plunger mounted on linear actuator.

 

 

 

 

 

 

 

 

 

 

 

 

The assembled syringe.

The assembled syringe.

All Officers to the Bridge!

Starship Bridge

In preparation for our Artemis Simulator that’s going to be at Maker Faire Milwaukee, we’ve partnered with Betty Brinn Children’s Museum to build a realistic starship bridge. Here’s what we’ve got so far.

Starfleet never produced an episode of How It’s Made, so we’re going to have to do a little guessing along the way when building our bridge. Obviously we still need to install the EPS conduits, Tribble-proof everything, and get the self destruct system up and running. But we’ve got nearly 80 days to get it all done.

Don’t forget to bring your phaser to Maker Faire Milwaukee to check out the final build!

Experiments in optics and image processing

After successfully mating a web cam with my microscopes (http://www.thingiverse.com/thing:216821) and telescope (https://www.youmagine.com/designs/web-cam-adapter-for-meade-telescope-eyepiece), I decided to design and print adapters to mount my Droid Turbo phone on the same scopes (https://www.youmagine.com/designs/microscope-adapter-for-droid-turbo-phone and https://www.youmagine.com/designs/droid-turbo-phone-to-telescope-adapter) so I could shoot higher resolution stills (21 Mp) and 1080p (and even 4k) video.   The telescope adapter fits over a Meade 32mm focal length Super Plössl eyepiece and provides about 47X magnification with the telescope.  I printed a similar adapter for my surgical microscope.

IMG_0995_crop

 

 

 

 

 

 

 

 

 

 

 

 

The telescope adapter firmly grips the phone and the eyepiece.

 

IMG_0993_crop

 

 

 

 

 

 

 

 

 

 

 

 

Initial tests were a little disappointing.  The combination of the phone’s camera and the telescope’s optics has significant pincushion distortion.  The image has only been mirrored L-R and scaled down (original is 21 Mp).  Note the lack of contrast (looking through 1/2 mile of humid air) and the curves in the power line and pole, and even the grass line:

pinch test original

 

 

 

 

 

 

 

 

 

A quick search found that the Gimp has built in transform tools to correct (or create) lens distortion.

 

gimp

 

 

 

 

 

 

 

 

It only took a couple minutes of messing around to get acceptable results.  Here’s the same image with the pincushion distortion corrected (whole image), contrast stretched and white balance corrected (rectangular area).  The pole, power line, and even the grass line now look straight.

pinch test corrected

 

 

 

 

 

 

 

 

 

And here’s the final image with all corrections and cropping applied:

final

 

 

 

 

 

 

 

 

 

 

Next step: photograph known square grids through the microscope and telescope and then create and save some preset corrections to apply with Gimp.

I wonder if something like this exists for video.  Hmmmmm…

 

 

 

 

 

Flaming Lotus is…

Flaming Lotus

Our Power Racing Series team is back for 2015! But, well.. we’re a little smaller. Right now it’s just Ed C. and me (Pete!)

But as you can see from the photo above, we have a body mostly primed. It’s actually been painted a bit more since this photo from two days ago. It’ll be ready to go for Maker Faire Kansas City in (less than) two weeks!

I can hear you saying “Yeah, a body is a great, but where’s the frame, the motors, wheels, controller, brakes, and all that jazz!?”

I present you with this CAD drawing. Everyone knows designing a thing is 95% of building a thing. So we’ve completed 95% of the work… now we have (less than) two weeks left to put it all together. Easy!

CAD Lotus

See you in Kansas City!