3 years ago I started participating in the Grow Beyond Earth contest.  It’s a collaboration between NASA and the Fairchild Botanical Gardens in Florida.  The goal is to create a device that will grow food on the International Space Station.  That sounded like fun to me!  Year one focused on designing the growing area to take advantage of the 0G environment and fit in a 50cm cube.   I was fortunate enough to be a finalist and walked away with some prize money.  I was not able to participate in the 2nd year but I am back in for year 3. 

This year the focus is on creating a robotic harvesting and planting.  If you want to read all about it you can do so at the Make:Projects link below.  This has been a fun project and I learned so much.

https://makeprojects.com/project/0g-garden—year-3-professional-entry

Ever get excited after seeing an YouTube video?  It happens to me all the time.  When I was Thomas Sanladerer‘s video on using an MSLA printer to make PCB’s I knew I had to try it.  In fact I have worked it into February’s Model Monday project.  This month we will be designing an Addressable LED strip control box electronics and all.  You might not know that Fusion 360 can do electronics design but after a few classes you’ll be up to speed and ready to design.

I have been looking for an excuse to learn more about the electronics design work space in Fusion 360 and I had a member request it as a project.  It’s great to be able to have electronics parts and cad design all in the same software.  This is going to be a fun one with lots of new things to learn for all of us.  Join us Mondays @7pm live or watch the recordings on YouTube at your convenience.

CP Terrarium

My first project was an attempt to learn some programming, some 3D printing, some sensor design, and combine them with a longtime hobby of growing carnivorous plants.

A Raspberry Pi 3B+ is the main control device.

1) It controls turning the lights on and off to match sunrise and sunset anywhere. Mine is set up to match the photo-period of their natural habitat.

2) It monitors the temperature and humidity and displays them on a remote dashboard that can manually override the automatic control.

3) Water level is controlled with a homebrew designed/built sensor. The sensor’s plastic element was drawn on Fusion-360. It was 3D printed at Milwaukee Makerspace. Water level status is also displayed on the dashboard and can be remotely run.

4) Coding is done with Node-Red, a graphical programming tool.

Node-Red Code

The actual terrarium is an uncovered 10 gallon tank. It has two species of Drosera  ( Sundews, a sticky leafed plant) and a Cephalotus. (Albany Pitcher Plant) Lighting is provide by a small LED fixture. Humidity and Temperature monitored with a DHT22 sensor. Water level measured with a CMOS Schmitt Trigger voltage division sensor. Remote viewing and control is done with VNC.

Real world progress is coming along. Code has been finished (until I get a better idea and redo it again) and checked. Temp/Humidity sensor is in place. Right now it’s only monitoring and displaying. Adding a heater and cooling fan is in the future plans. 3D printed sensor has been fabbed. Assembly, electronic circuit building, and testing will be the next phase I approach. Following that will be the addition of a water pump or solenoid to automatically replenish the water level when it drops.

TLDR version: Raspberry Pi monitors or controls a CP Terrarium’s lights, temperature, humidity, and water.

Node-Red Dashboard

3D printed sensor

We recently added a multi-stage filter to our laser cutter exhaust system which gave us an opportunity to buy things from American Science & Surplus and build a handy electronic gizmo.

More info about the project can be found on our wiki:
Laser Cutter Exhaust Filter Pressure Drop Monitor
Laser Cutter Venting System v6.0

Harvey got a new power supply for the CNC Mogul from Automation Technology Inc and asked me if I could help him document the replacement process. It was pretty simple and went very smooth. We’re lucky to have Harvey around as a member, and I’m glad he takes care of the CNC Mogul.

Check out the video below to see Harvey replacing the dead power supply with the new 36 volt 9.7 amp model he got from Automation Technology Inc.

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.

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

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!?”…

I present to you, failure #2: The small, drill-wound electromagnet:

This magnet was made from 28ga wire, and also ran at about 18V. It didn’t pull much more current than the previous one, and was also only able to lift ~3-4 of the 7/16ths nuts. I remembered Tom had a GIANT SPOOL of copper in his area, so I asked if he minded if I used a bunch of it. It turned out to be 17ga! After searching the ‘space for the right core (initially, a bolt, as shown in the previous photo), I found a nice piece of 1/2″ bar stock, and a piece of PVC tubing that the bar fit into perfectly. Once again, the drill came out, and I wound a much larger electromagnet:

This guy means business! It metered out at about 2.3 ohms. I fired it up with the bench-top power supply in the electronics lab, which immediately went into current-limit mode. At 6V DC, it was drawing 2.75A! I brought it over to the pile of nuts and it picked up about 15 of them! SUCCESS! According to Ohm’s law, if I run it at 12V, it’s going to draw close to 5A of power.. But the resulting field should be even stronger!

The original plan was to wind the copper around the PVC, but I would it too tightly and wasn’t able to remove the PVC afterwards. Oops! There was some debate as to whether a U-shaped core would be best, so that’s what I worked towards. After some testing, I found that the U-shaped core didn’t help at all, so I had Dan help me turn the u-shape into an eye. This will make it easy to suspend from a string.

Here’s a comparison of the three magnets to give you an idea for size..

Stay tuned for more photos of the electromagnet crane build!

(Also, for the Monty Python fans.. working on this project made me feel a little like the King of Swamp Castle must’ve felt..)

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.

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.