MagneTag

The Idea

I love magnets. What kind of dark magic powers their mysterious forces?  It is questions like this that led me to study physics at university.  My Buckyball set is my favorite desk toy, it is my go-to fidget device.  Several years ago I was playing with them when an idea struck me hard., an idea I could not get rid of.   You could use magnets as an electronic scoring system for tag. I do enjoy a nice game of tag.  Back in the day my friends and I would run around the back woods of South Carolina shooting each other with paintballs.  It was super fun, but the sport is not all that accessible.  You need a some disposable income and a high pain threshold (especially in winter when the balls froze).  On top of that you could count on an argument about someone being “out” or not.  Magnets could be encased in soft foam darts or balls (sound familiar?) that you could could collect and reuse in an indoor setting; detecting them electronically has been possible since Maxwell wrote down his famous equations of electromagnetism.

There are several ways to detect a magnet electronically.  You could use a reed switch or a hall effect sensor, but nothing is simpler than a coil of wire.  Electromagnetic induction is a very useful phenomenon, and it is found in technology all around you.

Studying physics was certainly inspiring, but my education failed me when I tried to build a prototype.  It turns out, making things is hard.  While I was trying to understand basic electronics, a new company called Arduino, introduced a product onto the market; I got one.  Additionally, a new magazine called MAKE had just been published, which was where I learned about the concept of a makerspace.   At that time in Milwaukee, a group of 10 or so had leased as small space in a turn of the century industrial complex that looked like a set from a Batman movie, where the bad guys are.  Over the years I have been working on this project at Milwaukee Makerspace, I have seen it grow into an amazingly successful institution in our community.

It didn’t take me long to start blinking LEDs on my Arduino, that platform is really easy to learn.  Learning about amplifiers and comparators took a bit longer, but after several failed attempts I was able to prove the concept. This video from below is from 2012.  That’s when I met Jason, who is holding the camera here.  He joined team MagneTag not long after.

I was pretty stoked about the proof of concept, and was excited to build a wearable system.  I learned how to etch my own circuit boards, 3d print enclosures, and wind my own coils on the sewing machine.

 

I spent a lot of time on this project.  More than I care the count to be honest.  But the process was actually very fun and challenging; there is great value in the journey.  I made many mistakes, but each one made the system better and better.

 

Once I started playing MagneTag for real, it was more fun than I had even initially imagined!  I also learned what it was really great for: foam noodle fighting!  Jason and I went all around Milwaukee testing our system with anyone that would give it a try.

We did not need to add a soundtrack to this. The dude brought his own in a fanny pack.

Posted by MagneTag on Saturday, June 21, 2014

Concept to Production

The game was so much fun we were totally driven to get it out into the world where everyone else could enjoy it like we do.  It was about this time that crowdfunding had become all the rage and we saw it as an opportunity to get our system into production.  Looking back it’s clear what we didn’t know could fill… a very large container…

 

Good Idea? Maybe. But not great execution.

The first mistake we made was a classic one: feature creep.  Of course it had to have Bluetooth. Bluetooth all the things!  We didn’t really have a plan for it, and the system was already pretty great without it. We thought who would want this thing without an app? It took us the better part of a year to make an app for the system and get the hardware going. When it was “done” it wasn’t all that awesome.  Bluetooth is slow; there was a painfully slow lag between the sensor and the smartphone.  The idea does have potential, but we were not executing it well. The only good thing about this excursion into software is that we were able to have my buddy Chris join the team, so now there were three. When you are doing something very challenging it really helps to have people with you on the journey.

 

 

 

 

 

 

The second mistake we made was building a product before understanding the market. I just wanted to build the coolest thing because that’s what I wanted to make.  I considered myself the target customer and nothing less than the best would do.  This prompted another near-total redesign of the system. I flippantly told myself that the added costs would be worth it and didn’t give it too much thought.  What we ended up with was very awesome, but it has to be for what we needed to charge for it.

 

The third mistake I made was also classic:  The Field of Dreams Fallacy.  If you build it they will come…No they won’t.  We launched our awesome new product on Kickstarter and failed spectacularly.   I looked at the site analytics, nobody came to the page. As an engineer I used to make snide remarks about the marketing department.  I no longer do this because it turns out that what they do is extremely important.  Even if you’ve made something awesome it takes a whole other set of skills to get people to see it.  I still haven’t figured this one out, but I haven’t given up.

Link to our second Kickstarter campaign

I made a thing!

This project began much like many of my projects at Milwaukee Makerspace have: an off-the-cuff discussion; in this case, with Lance Lamont about a possible project for Maker Faire Milwaukee. After a few rounds of discussion, we came up with the idea of an electromagnetic crane. I decided I’d attempt to build one similar to this style, and that I’d start off with the magnet. I purchased several small electromagnets from Tom‘s favorite website, Banggood. Thus, the MicroMagnetArray was born:

em_array

And failed miserably. Running at 18v (50% more than its rated voltage!), it was only drawing ~200mA, and could only lift 2-4 of the 7/16ths nuts I’d borrowed for use as ballast.

So my inner maker came boiling to the surface and yelled at me, “why not wind my own!?”… Continue reading

Time Delay Relay

Time Delay Relay

I’m working on a project that requires two power strips to be turned on in a sequence. The first power strip powers 6 HDMI displays, and the second one powers 6 computers. The displays have to be on before the computers so they sync properly and get the correct resolution. Since I can’t rely on a person to do this properly, automation is the answer.

My first thought was to use something like a PowerSwitch Tail with a microcontroller to trigger it. (There’s also a cheaper kit version available.) The issue with this solution is that I’d need a microcontroller, and a power supply for the microcontroller, which are more parts, and more points of failure, and take up more space. I also considered using a cheap relay module, but ultimately I was overly complicating the whole thing. Also, I want this to be reliable, and sticking a 5v power supply, a microcontroller, and a relay in a box for three years seemed a little risky.

What I really needed was a “Time Delay Relay” which is a device that can get power, wait X number of seconds, and then power on another thing. There’s a whole bunch of them you can just buy! Time Delay Relays are not cheap though… This one is under $40, but you’ll probably also want the socket, which puts you closer to $50.

Luckily, Milwaukee Makerspace is filled with all sorts of old industrial “junk” and we have a bunch of these sitting on a shelf! Brant (you know, the guy who made an Auto-Off Timed Outlets from an old microwave control panel) helped me find one and get it wired up last week. It works great!

I used a $3 extension cord to provide an easy way to plug it into the first power strip and plug the second power strip into it. There’s a dial that lets you set the delay up to 10 seconds, which is more than enough for my needs.

Time Delay Relay

If I’ve learned anything from this project it’s that even though you think you might have a good solution to a problem, it’s still worth asking others (at the space or on the mailing list) because you may get a better solution, and may even get the parts you need.

Auto-Off Timed Outlets

If you’re like me, you’ve left a soldering iron plugged in once or twice.  Hopefully you’re also lucky like me and it’s never started a fire.   Occasionally I’ll grab something off our Hack Rack and take it apart.  A) It’s fun and B) it helps cut down on the ever-growing pile of appliances in the East Room.  Recently I focused my efforts on a microwave oven.  During my salvage operation I managed to extract one plastic fan, two thermal cutout switches, a transformer, the magnetron, a huge capacitor, and the controls.  I soon realized that what I had in front of me was a digital timer wired to a normally open relay.  I couldn’t immediately think of something to do with it, but it seemed too good to toss or disassemble further.  About a week later I decided to wire it to a pair of 120-volt receptacles.  Voila.  Any appliance with a standard plug can be set to run from 00:01 to 99:99 before powering off.  Just press “TIME COOK” then enter the time in minutes and seconds, then start.  The relay closes the circuit and the outlets are energized.  When the timer runs out, a piezo buzzes and the outlets shut off.  The relay on the microwave’s circuit board is 120-250 volt at 16 amps, so I’m fairly comfortable it will handle one or two 40-watt soldering irons.

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