hu-LED hoop

The basic idea for this project is to program a score tracking feature into a hula hoop and use LEDs to communicate to the user how many revolutions they have completed so they don’t have to stop and check their score.

The Building Process



  • Soldering Iron
  • Hot glue gun
  • Wire stripper
  • Pliers
  • Wire snips


Measured the length of the tube and decided to use 40 LEDs alternating in groups of three and one.

The next step was to spend most of a day soldering all the LEDs back together in a long strand and testing them periodically to make sure all the lights work. After soldering the wires onto the pads, I coated all the of the contact points with hot glue to make the string more durable and help prevent shorting out the system.

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A common challenge with physical computing projects is figuring out how to power them. I had a 5V power bank so I took it apart and found out that it happened to fit perfectly into the tube. I liked that this power bank has a on/off button built in, which allows it to function as a power switch for the whole project.

Cutting some notches out of the end of the tube set the components more securely.

In order to get the micro-controller to fit in the tube, I decided not to solder header pins onto it, and instead soldered the three wires from the sensor and the three wires to the LED strip directly to the board.

Because the tube is translucent, the sensor wasn’t triggering the score function in bright sunlight, so I took a piece of heat shrink tubing and cut a small piece to limit the field of light hitting the sensor. This worked quite well. The company I got the tubing from included a short piece of smaller diameter tube that fits snugly inside the hoop to give a hula hoop some structural stability, so I used this piece to house my sensor.

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Then, I folded up the short USB/micro cord I had inside behind the sensor breakout board so that when the hoop is completed, the USB plugs into the battery pack. This layout also makes it easy to open it up and reprogram the pro micro.

The final step was to create an enclosure using the moldable plastic to create a sort of cage to keep the two ends of the tube together. Additionally, I made some counter weights to help balance out the weight of the battery and the electronics so the hoop rotates more evenly.

The Programming:

Writing the code for this project, I came up against way more obstacles than I would have expected. The concept is pretty simple: if the light sensor level reads below 5, then the “score’ increases by one. I originally wanted there to be nine “levels” that would trigger different light animations so the user would know when they hit a certain number of rotations.

Unfortunately, the program got glitchy after counting to 30, and the pro micro didn’t seem to be able to handle 9 different animations from the ALA library, so I had to limit the counting to a score of 20 and automatically reset to 0 at that point, and limit the number animations to three. If the score is less than 5, then glowing blue, between 5-10 a glowing red, and between 10-20 bright flashing red and yellow.

Link to gist

What I Learned

Embedding electronics into an odd shaped enclosure is an interesting experience.  I ended up having to tie a metal screw to the end of a piece of string and then pull it through the tube using a magnet so I could then use the string to pull the string of lights into the tube.

Also, it turns out that using a light sensor is perhaps not the best choice because it only works if the is a significant amount of ambient light, and the best environments for a light up hula hoop are lower light situations.

Here is a short video of it working, but it is a little hard to see the LEDs in the daylight:

Finally, I really like working with the ALA Library, but found that it has some limitations if your using a board with limited memory.


I would like to experiment with some different sensors, accelerometer, pressure sensor, and maybe just a button to see if any of these work better for lower light conditions where LEDs show up better.


It would also be fun to get a radio chip and play with using the hula hoop as a controller interface for a separate installation.

For example, perhaps the faster a user spins the hula hoop, the faster a toy hula girl dances, using some motors to make the doll move in matched speed.

Analog I/O and Enclosure

Part 1:

Build an interactive circuit that uses at least two different variable resistors (inputs) and some kind of output (sound, light, movement).

For part one one this exercise, I played around with several different sensors and the first circuit I built used a slider, a flex sensor, and a photo resistor each mapped to control the brightness of three different colored LEDs.


After having good success with this experiment using multiple sensors to control multiple lights, I wanted to try using multiple sensors to control a single RGB LED. The photo sensor wasn’t “playing well with others” so I replaced it with a potentiometer.


This gave me an idea for Part 2 of this exercise to make a color blending sort of toy, using three potentiometers, so rebuilt the circuit with three regular LEDs, red green blue, and one RGB LED. Each potentiometer controls one color. The Red pot is mapped to the single red LED as well as to the red pin on the RGB LED, so when it is turned it controls both.


Part 2:

Build a custom enclosure for your project – the enclosure can be soft or hard but it must fully hide your electronics.
Parts: variable resistors, photo resistor, micro-controller, breadboard, fabrication materials

I decided to make a color mixing toy, so it seemed appropriate to make the enclosure in the shape of an artist painting pallet.

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After using the laser cuter to trace out the shape on cardboard, I needed to use an exato-knife to get it out of the sheet.

The cardboard I found in the recycle bin was double thickness so I cut through the layers in a ring around the holes to mount the translucent material that will allow the LEDs to shine through.

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Two layers of clear plastic sheet with two layers of white tissue paper sandwiched in between gave me the appearance I was looking for. Trace and cut out pieces that fit into the recesses.

Created an inner structure with shallow cardboard tubes that give space for the Red board, power pack, and house the potentiameters and LEDs.

I found that one LED wasn’t bright enough to light up the little pods, so just wired two together using small proto boards to consolidate the wires.

then added the potentiometers threading the wires in through opposing sides to give it some support and to make sure the LED wires don’t touch it.

Cut a hole in each white plastic piece and then mounted them into the pallet with the pot/LED pods, securing with hot glue.

I wanted some unique knobs for this that looked like blobs of paint, so I made some using some modeling foam and craft paint.

Adding all the wiring in was a bit messy, so I combined all the power and ground wires on proto board, and made sure to label each wire as I went so that hooking up the microcontroller would be easier.

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Here is a rough attempt at a schematic of the wire hook up:

Final step for components was power. I have a 5v power pack from a previous project that happened to fit, so added that. Also added a rim so that when the bottom piece is attached, none of the internal components show.


I’m quite happy with this as prototype. The lighting quality isn’t quite as good as I hoped, but different types of LEDs could solve this if I had a longer time frame to research and experiment.


In daylight, the lights are more difficult to visualize, so I put it on the floor under the table so it would show up brighter.

Here is the code:

twirLED Final Post


The basic idea for this project is a skirt that reacts to motion and lights up when you spin around on the dance floor. For social dancing like blues, swing, and salsa, the “show off” moment is when a dancer spins, so I wanted a skirt that only lights up at that time.

The function is accomplished by running a simple program that reads the position in the z-axis of a 3-axis sensor and triggers a light strand to blink if the reading is above a certain value.

Overall, I was pretty happy with the way my first prototype turned out, however, I became immediately aware of a construction problem during the first live trial.

The sensor and, pro micro and LED strips performed great, and as expected, but my solder joints on the LED strips around the hem of the skirt began breaking almost immediately.  I did some research into other LED and wire products and found an alternative way to construct my second prototype, which is proving to be much more durable.  Here is a link to the Instructable I wrote if you are interested in all the nitty gritty details of this project and a couple demo videos of the second prototype below.

The only issue I have yet to resolve is that the 5V power bank, of which I have tried several, turn off if there is not enough power being drawn off of them, but all you have to do is turn it back on, and everything works fine, so I don’t know if it is even worth addressing.  Of the ones I tried out, I think I prefer the Sparkfun version because it has a switch that works to turn it on and off and it has a small digital display that tells you what percentage of charge the battery has left.

Finally got all the info together and organized to post an Instructable for this project if you are interested in recreating your own version.  I also entered it into one of Instructables contests, so please like and vote if you enjoy it!  Thanks.

Click here to check out Instructable! 


Cat Walk


Four legged, middle-aged, dark haired, male.


Being too short to have a good perspective of a room, he is always in search of a perch, and because the canine housemate steals his food if his bowl is near the floor, he has to jump up and down from the top of a shelf that is too high for comfort.

Design Idea:

Upholster the the top of a shelf at a comfortable height for the little man to hang out and walk around on that will also serve as some storage space for the two-legged inhabitants, allow him to get to his feeding spot more easily, and give him a climbing option in the house.

Supplies Used:

Used almost entirely leftover bits and pieces from previous projects and things I already had sitting arround:

  • 2 Ikea Trones storage bins
  • Pine boards: 1″x 8″ and 2″x 2″
  • An old cardboard mailing tube
  • Upholstery fabric
  • Staple gun and staples
  • Decorative upholstery tacks (this is the one thing I had to buy)
  • Miscellaneous assortment of screws and brackets

Lessons Learned

Spray adhesive doesn’t really stick to memory foam.

Memory foam isn’t great for upholstery foam because it is more difficult to make it even and smooth when covering it with fabric under tension.

Regardless, kitteh approves!


Click Here to see Instructable!



I was fortunate to have the wonderful opportunity to work with the MindScribe team to help develop soft user interfaces for their work.  I did this project as independent study for a semester working on tactile fabrication.  Some goals for the user interface were low cost and using local animals for educational setting.

stripes“MindScribe is on a mission to help young children tell their stories. We use puppets and talking stuffed animals to ask kids questions about their 2D & 3D creations. By creating and sharing their stories, children grow their skills and their connections with the world. And through their stories, caregivers learn how to better support incredible, individual growth”

This project was entered into the openIDEO Early Childhood Innovation Challenge and will be presented at HRI 2018 in Chicago and IUI ACM 2018 in Tokyo, Japan.


The Process


  • stuffed animal from a secondhand store ($2)
  • Fabri-Tac (fabric glue)
  • Seam ripper
  • Scissors
  • Zipper or velcro
  • Needle and thread
  • Clothes Pins

Step one: find a suitable subject..

I checked the local Goodwill first to see what I might be able to find.IMAG0441


I was able to get these guys for $2 apiece, and chose to start with a few different body shapes and sizes to see what might work best.   IMAG0450

Step 2: Wash and Prep

Make sure to wash the toy, especially if it is pre-owned.

Step 3: Making the pocket:

There are several ways to do this.  I sewed some of them and created some just using fabric glue.  The glue option is quicker and more approachable for anyone who doesn’t have a sewing machine on hand.  This is simple construction and doesn’t have to look pretty since it is going to be inside the stuffed animal.  The purpose is to make it easy to get the phone in and out and to keep the stuffing from escaping.




This guy is pretty small, and only smaller phones would fit inside so didn’t work for everyone, but with a small phone, he stands up really well because he can sit in the tripod position.






This guy presented a bit of a challenge because he can’t stand up on his own, so I added a skeleton by bending a wire coat hanger to fit in his feet and tail to create a triangle base and then up in a big loop in his head.




Grumpy GopherIMAG0550.jpg

The look on this one’s face is just too cute.  I took a different approach to adding a pocket to this one.  Instead of a zipper, I decided to see if Velcro would work as a closure option.  Additionally, because this one has a larger body than the others, I made the pocket opening horizontal instead of vertical.












This bear is another example of the tripod position where the animal sits with it’s front feet between their back feet which adds some stability so the furry friend doesn’t fall over when a phone is inside it.







Thermochromic Textile

First step is to make something integrating a yarn dyed with thermachromic pigment.  I decided an ear warmer would be a good platform as the heat wire element might enhance the ear warming function as it heats up to change the yarn color.

I like the way the yarn blends in.  Makes for a more dramatic reveal! Now to test it.


Thanks to Laura and Unstable Design Lab for providing the dyed yarn and Wayne for the assist with testing the needed wattage.  I’m still unsure of how to actually functionally power this project, but I think it is an interesting idea.

Sew Something…

Step one:

Find two fabrics that you like and cut out all the pieces.

Here are some instructions on that:

-measure your waist and divide that number by 6.28
-fold the fabric in quarters and use the number to draw the radius from the double folded corner.
-decide how long you want your skirt and measure it out from the first radius making sure to leave a seam allowance.
After cutting the circles and waistbands, I sewed the bottom hem of the two large circles together with the right sides facing, and then turned it inside out and sewed the hem.  this allows the hem to be neat and beautiful on both sides.


Here is the finished hem



Because this  skirt uses two woven fabrics that don’t have much stretch, I put a zipper in, so next step is cut the skirt where i wanted the zipper to go.


Next comes the waist band.  using the same method with the main skirt, sew bands together with right sides facing along one of the long edges then flip and resew.  this is the top edge of the waist band
There are several methods for attaching a waistband.  I pinned the grey side first, right sides together and sewed them then, turned the skirt over and turned the edge under and pinned the print side


Waistband attached!


Now for the zipper!

this is a somewhat difficult part
I used a reversible double sided zipper.  The one I liked was actually for a sleeping bag, so I had to cut it way down!
Fold fabric under and pin the zipper in place
Be careful of the pins and turn the skirt inside out and repeat