Wearable Platform

Once the mechanical components were working well, the next step is making it wearable.  The original idea was to make it as a sleeve for the lower arm, so a pattern needed to be developed.

One common method used by people who make their own costumes, cosplayers, uses a thin plastic and tape.

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First step is wrap and secure plastic around the area a pattern is wanted.  The plastic can be saran wrap, a grocery sack, trash bag, or anything similar.

Covering the plastic in between the taped boarders, making sure to keep the tape as smooth as possible, is the next task.

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Carefully remove with scissors, trim off the excess plastic around the edges, and cut the piece in half.

Using one of the halves, trace the shape out on a piece of scrap card board.  Then draw a second line half inch away, all the way around the shape for a seam allowance.

This pattern is then used to cut out the needed layers of fabric that will house all the components for the second prototype.

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The Power Struggle

As with all wearable technology projects I’ve worked on, power is one of the big challenges.  There are all sorts of really cool things you can make, but as soon as your system requires 12V to run, it becomes unwieldy and not really wearable unless it’s a backpack to start with.Screenshot_20180731-100826_1_1.jpg

 

here is a fairly compact 12V battery pack, I found on Amazon, but it still weighs almost a pound.  Doable for some applications, but wouldn’t work to wear on the forearm and at $34 each, makes it difficult to have a couple extra on hand

 
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In the past, I have been very pleased with Sparkfun’s 5V rechargeable power bank for both function and affordability.  It is compact and light weight, comes with a cord to power your project and recharge the battery.  Additionally, the power button on the battery can double as an on/off switch for the entire project.

 

The big problem with the initial prototype is that the solenoid valves needed 12V to open and close.  With a bit of digging and research, I was able to find some 5V solenoids as well as a mini air pump, and ordered some for the next iteration of this project.

For my initial prototype and testing, I was using an Arduino Uno and a Sparkfun RedBoard for the micro controller, however, I’m going to switch to a much smaller ProMicro board now that the code has been tested.

First Prototype

IMAG1513.jpgUsing my concept sketch, I created a digital version  of the design in Illustrator.

With the laser cutter and assistance from and lab mate, we cut out a piece of non-adhering paper to sandwich between the heat sealable nylon.

To get the pouches in the prototype to bend, I referenced the work done by the MIT Media Lab. “aeroMorph – Heat-sealing Inflatable Shape-change Materials for Interaction Design

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After fusing the nylon with a heat press, but leaving one side open, the small valves were installed, and then the last side sealed.

 

 

Test with a hand pump:

This wasn’t quit the dramatic shape change I was hoping for, but not too bad for a first try.

The next step was to hook it up to a system with tubes, an air pump and small solenoid valves.

Test Code

Even with all the components wired to a bread board, all the components, except for power, for this project fit into a small flat box.  Still a bit big to wear on your arm, but a few adjustments and I think it will work.

Functional Code with Buttons

 

The prototype worked pretty well.  The level tracking function worked, and partially inflated the correct pouches.

Problems:

  1. Power!  The current system needs different power sources to run the valves, pump, and microcontroller.  Additionally, a 12V battery pack will certainly interfere with the “wearability” of the device.
  2. Shape changing is too subtle.  Need to make the pouches bigger, or change the angle of the fused shape in middle of pouches, or separate the pouches and make them individual, or rewrite code so there is more air pressure flowing into each pouch, or some combination of these options.
  3. Material.  After running the test code for a while, some of the pouches started to leak and wouldn’t inflate all the way.  I’d also like to look into getting plastic fixtures for attaching the pump to the pouches to lower weight and cost.

 

 

Wearable Soft Haptic Controller

Working in the “ThingLab” over the summer on a couple different projects involving haptic control interfaces and pneumatics inspired the development of this one.

According to Google, the definition of haptic is: “relating to the sense of touch, in particular relating to the perception and manipulation of objects using the senses of touch and proprioception.”  In controlling the many systems we interact with daily, there are situations where visual faculties are occupied, obscured, or permanently impaired so discovery and control are delegated to our hands.

As a first attempt, I thought a simple controller defining levels with up and down selector pads would be useful and have broad application(volume, fan speed, etc…).  The outer forearm seemed like a good place to attach it to a human body as there will be minimal interference during activity and can be worn over clothing if needed.  A Vambrace in terms of armor.

 

Here is a first concept sketch of what I’m thinking.  Some air-tight pouches hooked up to tubing that connects to a tiny pump and some sensors embedded under the (+) and (-) to act as control buttons.

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first concept sketch

 

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

Supplies:

Tools:

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

Schematic:

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.

Improvements

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.

hula

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

error

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.

http://alpha.editor.p5js.org/full/ryN6Fp-1m

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.

 

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misc

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.

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existing products:

http://vhoop.net/

https://www.amazon.com/Hasbro-B0618-Twister-Moves-Hoop/dp/B00NHLA15I

https://www.amazon.com/Twister-Rave-Skip-It-Game/dp/B00ABEP654

Components:

  • 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

Enclosure

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