Internet of Things Hackday Trip Report

Last week I attended the Internet-of-Things Hackfest at Minnetronix is the Twin Cities.

Dan McCreary working with a student on the Moving Rainbow Arduino Kit

Here is a quick summary of some of the things I learned last week:

1. Students LOVED the new Moving Rainbow kits I built.  Although some designs worked better than others.
2. The spark.io device is wonderful but still lacks some features that would make it easy for students to use in classrooms.
3. Getting IoT remote devices  to work requires specialized skills (like C parsers) that many of us don't have.
4. When students get their own ideas for projects they get laser focus
5. Hackdays are a lot of fun!  They are great ways to meet people and learn from others.

I had two roles at the hackfest.  I helped setup and run the "Kids Room" for the hackfest and I did a (very) little work in the Lumière lighting team.

For the Lumière team I mostly helped a few people to learn how to solder wires the LED strips and use heat shrink to secure the wires.  The other two guys on my team (Daniel Feldman and Alan) had much better programming skills and experience with other platforms like the Raspberry Pi.

I did spend many hours working on building an XForms, REST, XQuery application for the spark.io.  And although I did get it working (video), it still needs a lot of polish to allow the commands to be flexible.  I also did get a few new patterns working:

1. Larson Scanner (Cylon)
2. Random colors
3. Candle flicker (simulate the light flickering pattern of real candles)
4. Up-down patterns
5. Swipe (redraw colors one pixel at a time)

Many of these still need to be parameterized with arguments such as color and speed.  However doing a general interface still needs work.

To get the Internet-of-Things (IoT) moving rainbow kits to work we need to send a specific "change color pattern" command to each device.  Since the spark.io interface only accepts a simple string, we need to parse the strings into a pattern of colors and motion.  However none of use knew how to use the strtok_r() function so we struggled a bit.  Daniel did a great job under pressure getting one command parser working on the spark.io, however we will need to refine it a bit more over time.

The ideal long-term solution is to develop a small "Addressable LED Strip Markup Language" as a domain-specific command language and write a parser for it in C that would run on the Spark.io.  This is a non-trivial problem for people that don't write C every day.  However I hope to spend some time thinking about the pattern name, color name, delay period syntax and perhaps coming up with a small BNF grammar.

Moving Rainbow Findings

Now I want to review some of the findings around a low-cost Arduino kits for students.

One of the dongle-style Moving Rainbow designs connected to an FTDI programmer

My primary interest is to understand what can we do to get students involved in STEM and to keep them on the strong math and science tracks in high-school and college.  Each time I engage with students I look for things that get them excited and want them to return for more.

My vision is to help design low costs kits that students could take home and show their friends.  These kits should be inexpensive enough that schools, libraries, and park buildings could have them for checkout, just like any library book.  Imagine a bookshelf at the library that contained 100 different electronic kits, each with specific learning goals in mind.

My experience has shown me that with some mentoring and some good electronics kits that many students can use internet resources to do a lot of work on their own.  However some students need a bit more encouragement then others.

This was one of the first times I had my newest collection of my "Moving Rainbow" kits on display.  When the students came into the room I encouraged them to pick up each kit and play with them.  Each of them has slightly different designs, packaging and switches.  When they flick the power switch on the 12-segment RGB LED lights came on and some of the kits had nobs and sensors that change the LED patterns displayed.  I tried to pay special attention to each of the students and they came into the room.  I noted what kits they picked up and what features they were interested in.

One of the things I learned is that there was little interest in the small-versions of the kits.  These were the ones that did not have room for the 12 pixels within the box.  These had a "dongle" design where the LED strip was sticking outside the boxes.  These designs pretty much failed, and looking back I can see why.  My reason to try them was that the smaller boxes were less expensive.  The larger boxes cost $5 or $6.  However, one of the students wanted to purchase the "dongle" designs.

The other thing to remember is that the logistics of getting the Arduino drivers working on both Windows and Apple systems is very time consuming.  Much of the first hour was getting the Arduino drivers working and the FTDI drivers (required for the mini-pros)  installed.

Several of the students did a "color wheel" lab where they had to mix the red, green and blue values together to make purple, yellow and orange colors appear on the LED strip.  The look on their faces when the strip turned either the right or wrong colors was priceless.  These were fantastic teaching moments!  On my TODO list is a "cheat sheet" for the color functions with pictures of color wheels.  This guide would start with functions to set a pixel to a specific RGB value and draw colors within for loops.

The moving color labs was a bit harder.  I need to continue to find good simple examples of lights moving up and down and get them pre-installed in the Arduino Examples area.  This is a great way to teach for loops and if/then/else logic.  As my sister and brother have told me, teacher prep makes a huge difference in students understand and lowering frustration levels.

One incident was that the students really loved the idea of creating a small wearable designs.  I had my "Altoids" example necklace as a demo to show them.  A few of them wanted to make Halloween costumes out of them.  And they were VERY motivated once they realized they could create their own costumes out of them.  At our final presentation to the entire group, two of them came to the front of the group to show their creations.  One of the students specifically thanked me in front of the entire group.  I wish all the students were this polite!

One idea is to have a "Arduino wearables" hackday around the same time next year.  This would require a lot of planning and some volunteer work by people with sewing machines.

What this taught me was that once students get their own idea of a creation it is like a fire-bolt of energy gets lit in them.  Their distractions disappear and they become laser focused on their task.  They seek whatever resources they can get to reach their goals.  Helping each student find their project is what these hackfests is all about!

I also met a few other people that might help us lower the costs of the packaging and find lower costs of the Moving Rainbow kits.  I still have more work to do to learn about placing larger quality orders for components and packaging on volume discount sites such as alibaba.com.

I want to reach out and thank everyone that made the meetup possible.  The sponsors and the people at Minnetronix should get a special thanks!

New Arduino Moving Rainbow Lab for Kids for Under $10

After participating as a mentor in the local Twin Cities CoderDojo  in Minneapolis at the University of Minnesota I found that there are two things that kids love: motion and color.  My prior experience with kids is that they love to take projects home with them to show their friends.  So here is the question - could we design an Arduino kit that kids could come to Maker events and actually take a working project home that has both color and motion?

At our local CoderDojo we wisely use the SparkFun Inventor's Kit.  If you have not seen this I encourage you to take a look.  Lots of nice components and a great guide (PDF). Many people undervalue the amount of work going into the guides for these kits.  Good writing is hard to find, are rarely included in many lower-cost projects.  However, since the cost of full Inventors Kit is still around $100 (without shipping) it is beyond the budget of most Maker events to let kids take these home.  So here is my answer: lets find a way to use the low-cost Arduino Compatible Pro Mini combined with a short strip of addressable LEDs in a kit that we could sell for around $10.

Here is a picture of my initial design:

Arduino Moving Rainbow Kit

I think this kit is perfect for kids since we have the wonderful colors of these amazing individually addressable LEDs as well as the ability to create "motion" by programs such as running lights.  The total cost of this should be around $10, depending on the options we use.

Now lets go through the components to verify that we can do this in the $10 price range.

Here is a place on eBay that sells the Pro Mini Arduino Compatible for around $2.00. Although I suspect that we could get them in quantity for less.  Note that these do not have a USB port on them.  More about that later.

Here is an addressable LED strip with 60 LEDs that we can find on eBay for around $17.00. You can cut these up into 6 strips of 10 LEDs each which gives you a price per kit of around $2.80. What is wonderful about these LED strips is that they only take two power pins and a single data pin to hook up!  I use the standard WS2811B which you can program with many libraries.  I have some sample code on github that uses the Adafruit NeoPixel libraries, however I have found other libraries work well also.  Keeping wiring simple is important for kids that don't yet have the fine motor skills (and patience) to wire up complex projects.

Now the last two components are the mini soderless breadboad (around $.70 in quantity), a switch and a power source.  In the kit in the photo above I am using a 3.7volt Lithium Poly battery taken from an old RC helicopter that no longer works. We could also use an external 3 AA or AAA battery holder for around $1.

I also added a power switch and a clear plastic polystyrene box I purchased at the Container Store, although a small plastic leftover box will also work well.

Arduino Pro Mini Rainbow Kit Parts List

1. Arduino Compatible Pro Mini $2.00
2. 10 element LED strip $2.70
3. Solderless mini breadboard $0.80
4. Battery holder $0.70
5. Plastic Polystyrene Box $2.50
6. Wire $.50
7. On-off switch $1.00

Total: $11.40 (with 3 AA batteries)  I have a detailed parts list here

I also suspect that if we purchase these in quantities of 20 or more the prices would come down a bit and we could get in under $10.

The biggest challenge is that each station must be equipped with a laptop with a FTDI basic breakout programmer with the Arduino software pre-loaded. The Arduino Uno (which runs about $25) does not need the FTDI programmer, but would be 10x more expensive for each Rainbow kit.  Getting these setup and configured is not easy.

I should also acknowledge that when we purchase items off of eBay or other sources, we are not using the official mini supplied by the fine people at Arduino.  However at over $20 these devices would not fit into our under $10 budget.  I still think that for other projects we should encourage people to use original Arduino hardware since the costs go to promote further open Arduino projects and quality educational materials.

Let me know your thoughts on this.  Getting high-quality clear plastic boxes that kids could take home, throw in their back and show their friends is still something I am working on.  I found one source here that I might try but any suggestions you have would be great.  I know other projects use simple baggies for their parts but these seem hard to use and show to others.

There are also other options is to provide a "night light" mode that you could plug into a wall outlet and not have to use batteries.  I have seen 5v USB "wall warts" for under $1.

Although I know that this is a very small project to get kids started in Arduino, I think it might be the platform that other projects could be added.  Creating a clock (12 LEDs required), putting sensors on to display temperature or adding accelerometers and magnetometers might be the next step for these kids.  The key is that they could take them home and show their friends and that keeps them interested and motivate to continue their work.

I also want to thank Gerd Knops for helping me get started on using the LED strips.  He is a brilliant engineer, a great friend and wonderful mentor to me.  I hope that what I learn from Gerd I can use to get more kids interested in science, technology, engineering and math.  We don't really have much time left to do this.