Chocolate Printer Cooling System Test

This week I attempted the first test of the chocolate printer cooling system.  The cooling system is intended to solidify the chocolate just after it leaves the extruder nozzle so that by the time the next layer is started it will have a solid layer to sit on.  The cooling system consists of a centrifugal blower with a brushless DC motor blowing room air into a styrofoam cooler containing a block of dry ice.  The air passes over the dry ice and gets chilled as the dry ice sublimates directly into very cold CO2 gas.  The chilled air and CO2 mixture exit the box through a port with a hose that will ultimately blow the cold air on the chocolate.  At least, that’s how it is supposed to work.  It blows air at -12C as measured via a thermocouple, but unfortunately, the air exit port ices up in about 2 minutes and blocks the air flow.

There are many possible solutions.  I can add a heater to the exit port to prevent formation of ice, or dry the air going into the box using a dessicant cannister or maybe just use water ice instead of dry ice if the higher temperature will still cool the chocolate adequately.   Maybe using an old miniature freezer with an air hose coiled inside would do the job.  It would be really interesting if I could use the waste heat from a freezer to keep the chocolate liquified and flowing.  Back to the drawing board!


Recently Arduino came out with the Arduino Zero. This is a neat 48MHz ARM Cortex M0 processor on a PCB with the same pin outs as an Arduino UNO. Existing 3rd party UNO libraries are a little hit and miss because some access the underlying hardware registers of the UNO. The Zero hardware registers are completely different from UNO. Still, the basic 1st party Arduino libraries work fine and I’m sure those 3rd party libraries that were twiddling the UNO hardware registers directly will start to support the Zero over time.

Anway, my curiosity was peaked by the ARM processor for the Zero the Atmel ATSAMD21G18. It turns out that the processor has alternative packages with higher pin counts. Same silicon, just more pins. So I gave the ATSAMD21J18 a try. In order to be able to use extra pins with digitalWrite, I had to add a small amount of code to a file called variant.cpp, but once done, I had a Zero with a nice chunk of extra I/O capability.

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Refreshing the Singing Pumpkin Display

I’m getting my original singing pumpkin display ready for BVNA’s Pumpkin Pavilion and Halloween. The original display was pure prototype electronics consisting a bunch of stuff from Adafruit: an UNO, a Wave Shield, a PWM/Servo driver, and servos. There was a footprint challenged custom PCB for a TDA7297 and some junk bin DC-DC convertors.


It didn’t look pretty, but it did the job for years. However, the new fully integrated prototype controller looks a lot snazzier.


There are still more design changes to come for this board, but it was really nice to see it perform as intended in my full display.

WISN 12 – Doors Open Milwaukee 2015

Screen Shot 2015-09-20 at 9.30.54 AM

Thank you again to Van McNeil and WISN 12 for their interest in Doors Open Milwaukee 2015!  Historic Milwaukee has done a phenomenal job promoting and organizing this event for the last five years.  If you haven’t had a chance to visit any of the 175+ buildings available this weekend, there’s still time Sunday from 10 AM to 5 PM.  Be sure to check the full list of participants at the official Doors Open website:

Ben will be “Looping the Lake” electrically!

Ben Nelson

Ben Nelson may be just a little bit obsessed with electric vehicles. Over the years he’s built an electric car and electric motorcycle, and he’s even got an electric riding lawnmower. He wanted to show the power of electric vehicles, so he decided to have his own “DIY Road Rally” and ride his Vetrix all the way around Lake Michigan.


All way way around the lake!? That’s 1,000 miles with no gasoline. He’ll be charging up a lot, but he knows where, when, and how to charge up.


People often say that electric vehicles are only good for short trips around the city, but Ben aims to prove them wrong. He’s also planning a full-length documentary film about his adventure…


Ben will also be appearing at Maker Faire Milwaukee in a few weeks, and he’ll be sharing what he learned on his trip. If you want to keep up-to-date while he’s out there, check out his blog or follow the journey on Facebook.

Loop the Lake

Here’s a short video of Ben driving away from Milwaukee Makerspace, on his way around Lake Michigan. Good Luck, and see you soon, Ben!

Singing Pumpkin Commercial


The Singing Pumpkin controller continues along. This new spin of the board corrects the previous flub-up of the reversed amplifier pin-out as well as adds USB and RS-485 to the mix. There are some minor errors on the board, but nothing that has prevented 90% of the board function from being validated. I need to check the recv direction on the USB, the Arduino-style reset pulse, and the RS-485 transceiver. With that I’ll be able to work on generalized firmware and PC software.

6th Annual Doors Open MKE!

This is your invitation to get out and explore Milwaukee!  We’re just one of +150 buildings that will be open to the public on Saturday, September 19th and Sunday, September 20th between 10 a.m.-5 p.m.  It’s free to attend and members will be present to answer questions and give tours.

If you visit, please enter at the north side of our building which is on Otjen Street.  While you’re in the area, be sure to check out the rest of our neighborhood.  There’s plenty of restaurants and shops within walking distance from the ‘Space.

See all the events and buildings this year on the Doors Open website:

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!