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.

Serial w/ P5JS

I had a lot of trouble with this.

kept getting weird error messages


but I was able to get some cool effects playing with the pots as controllers and putting the background in different parts of the code to wipe the canvas clean.

the eye

I tried to change the output to something other than the LED brightness being set to where on the screen was clicked, but was not able to get anything else to actually work, so I left that code in place and it works fine.

So my final is not nearly as interesting as I had hoped, but it’s sorta fun to play with.

click anywhere in the canvas to reset the background to a random color.

one end of the random color lines is set by the mouseX and mouseY position and the other end is controlled on the X axis by one of the pots and on the Y axis by the other.

this allows you to draw interesting shapes.




Project Pitch

HuLED Hoop

Growing up, some of the toys I played with were hula hoops and the “skip It,” which you put it around your foot and spun it around and it kept track of how many revolutions so you could try and beat your best score. The problem was that you had to stop before you could check your score.

I think it would be fun combine the 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.

I did some research and found some hula hoops that light up and some that track your score, but didn’t find any that combine the two.

Additionally, it might be fun to integrate some copper tape into the design on the inside and outside of the hoop as a switch to trigger a light feature for users who like doing tricks spinning the hoop around their body with their hands.


existing products:


  • sensor (photo resistor, or a button, and or a motion sensor)
  • microcontroller, I’m thinking a pro micro because it would actually fit inside or a micro:bit that could send the score out and could possibly sync with other hoops.  I have a couple of each of these to play with
  • LED strip
  • rechargeable battery


  • Plastic tube with an internal diameter large enough to house components
  • connectors to make the pipe hold it’s shape.
  • decorative tape

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:

Digital I/O

Part 1:

“Solder a circuits from Monday to a prototyping board (2 leds in series or parallel).”

For part one, I remade my in series circuit by soldering all the components to a small perf board.  The result was a cute little breakout board with three tiny green LEDs, one 100 Ω resistor and a tiny button.  Simple but useful

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Part 2:

“Build a circuit with 2 or more digital inputs. Use LEDs (regular or RGB) or neopixels as outputs. Program your microcontroller so that each input has a unique output.”

Parts: micro-controller, breadboard, neopixel strip, button, switch, LED, resistors.  

My idea was to have a circuit that has an “on/off” toggle switch and a button that, when pressed, lights up a green LED and changes the light animation from  slow blinking blues and purples (Chill mode) to brighter flashing reds and yellows (Burn mode) on a neopixel strip.

schematic showing hook up of micro-controller, two switches, one LED, and a short RGB LED neopixel strip.

I had a bit of trouble getting the buttons to work at first, but then our instructor pointed out I was missing part of the code.  After working out that hang up, I was able to get my light components up and running.  I like working with the ALA (Arduino Light Animation) Library.  This library has some nice “twinkly” options that I’ve really enjoyed using in other projects, and it is easy to add to the Arduino IDE.

Test of the button and toggle with green LED


Here is the code:

Final video

Hello Object

What I hope to learn in Object:

-more about calculating what resistors and power sources are appropriate for setting up a circuit.

-more experience programming sensors and actuators with more complex functions

What I already know:

I am pretty familiar with basic electronics and programming Arduino from past classes in ATLAS, and I have been building, sewing, and creating things for as long as I can remember, so I would say that fabrication is my strong suit.

Project ideas:

Some things I would like to build

  • Hula hoop that counts revolutions, and/or speed, lights up in different patterns to based on inputs, and shuts off after a set time of inactivity.
  • LED clock with a unique time display
  • twirLED for him, using micro:bits to communicate back and forth.

Lab 1

Build 2 bread-boarded circuits – one with 2+ LEDs in parallel, one with 2+ leds in series. Be sure to use appropriate resistor values for the LEDs in your bread-boarded circuits.
Parts: jumper wires, breadboard, LEDs, resistors, power supplies, barrel jack connector, voltage regulator.
What to post: photos of each working circuit, schematic drawings, and a written explanation of what you made.


mail me a link to your post.

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!