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Making Glove One

posted Jun 2, 2012, 3:33 PM by Bryan Cera   [ updated Jun 6, 2012, 6:07 AM ]

FINALLY!  The build detail for Glove One has arrived.  If you prefer the Instructables format, check that version out here.

For this tutorial, I'd like to take you through my process of creating Glove One, a functional cell phone that you wear on your hand! I've made a few tutorials in the past, but this one I see as the first time I've been able to give something back to the online communities of makers I've been learning from.

Any of the processes involved in this tutorial can easily be applied to any project in the realm of hacked electronics, DIY hardware, or digital fabrication. That said, I hope you enjoy: Making Glove One.


There are two different ways one could attack this project.  You could start from scratch, like I did, or you could work from the cad files I've made freely available here.  I created a parametric design for the finger segments, so they are pretty easy to modify to fit different hands - see 'Step 4: Drawing the virtual model' for more info on that. 

If you choose to start from scratch, I'd image the entire build would take about two months (not including delivery times for components or outsourced parts).  That's of course assuming you already have a bit of experience with a CAD program and know your way around a soldering iron.

If you start from my cad drawings, you could bang our your own Glove One in less than a month.

That said, I will start this tutorial by laying out all of the materials and tools I used for the build, and provide links where I can.


Materials used for the project:

- masking tape
- electrical tape
- shrink tubing
- surface-mount tactile switches (KSR251G
- custom 3D print from Ponoko (see 'Step 5: Digital Fabrication')
- sheet metal components cut by Ponoko (if you don't cut your own)
- micro nuts and bolts (microfasteners.com)
- extension springs    (from Small Parts on Amazon)
- a used or new cell phone (I used Burg Watch Phone "Midnight Black")
- zap-a-gap epoxy    (on Amazon)
- plastic-bond spray paint (I used 'Fusion for Plastic' by Krylon)
- plasti-dip (from Plasti-Dip on Amazon)
- 3in x 3in x .06in PETG Sheet Plastic (I used scraps, but can find on Amazon or Midland Plastics)
- 3in x 3in x .06in Acrylic Sheet Plastic (I used an old scrap, but can find on Amazon or Midland Plastics)
- .5in x .5in copper foil OR copper foil tape (on Amazon)


Required tools for the project:

- digital camera OR scanner
- soldering iron
- tweezers
- small screwdriver
- exacto knife
- 600, 600, and 1200 grit wet-or-dry sandpaper
- heat gun


Other useful (but not required) materials/tools for the project:


- card stock or manilla folders
- several short wooden dowels
- reusable poster adhesive
- de-soldering wick
- all-purpose cleaning agent
- metal files and/or sanding sticks
- dremel tool
- vinyl plotter (I bought a Vinyl Express for only $250 and it has come in handy for tons of projects!)
- 8in x 10in x .02in sheet aluminum (if you plan to cut your own metal components - from Small Parts on Amazon)
- CnC mill (if you plan to cut your own metal components - I used a friend's Taig Desktop CnC Mill)


STEP 1: Roughing out a plan.


Once I decided on what exactly the project would be, I had to make a rough plan of action.  First, I needed to decide whether to attempt to build a cell phone circuit from scratch, or to hack an existing cell phone to integrate into the glove.

Because I knew this was already going to be a pretty complex build, and I wanted this instructable to be accessible to as many people as possible, I decided to go the hack-a-phone route.  However, if anyone were interested, the High-Low Tech group at the MIT media lab has created an awesome open-source cell phone that could fit into this project nicely.

But hacking an existing phone would employ one of my favorite low-tech tricks for modifying electronics: button extensions.  This technique is VERY simple and can be used to quickly make really weird and fun interactions with all kinds of electronic devices.  Essentially, you just crack open the device, remove existing switches or button membranes, solder wires to the copper-clad leads, and solder your own buttons/switches to the other ends of the wires. Here's a quick illustration: 


I'd imagine a similar technique is used for projects like this NES controller coffee table:


As a demonstration of how simple yet effective this can be, I made a quick little NES controller hack of my own:



Anyway, this method of hacking an existing device would be the cornerstone of the Glove One project.  I'd use this method for "extending" buttons from the phone's circuit board to my fingers, as well as for the microphone and speaker of the phone.


I also decided that I wanted to make a mechanical, armor-like glove rather than a fabric one.  Robots FTW!


STEP 2: Creating a paper prototype.


It isn't completely necessary, but I thought it would be helpful to create a mannequin for mocking up a paper prototype of the glove.  The quickest, cheapest, and easiest way I've found for making a quick plaster mold is this stuff called "flex wax".  Melt it in a slow cooker, dip your hand a few times, and poof!  Instant hand mold.



Cast in Plaster of Paris:



For the first mock-up, I used a tailoring technique called "draping," where I essentially wrapped the mannequin in card-stock to get the basic shape of the glove.  Then, I cut out sections to create discrete parts for each finger segment.  I cut these apart and flattened them out to create a pattern. 





Rather than making a different pattern for each finger, I used a photocopier to rescale the same pattern, then selected different sizes for each finger.  The paper prototype didn't need to be perfect or look amazing, as it is really just the first step in creating the virtual model of the phone, which I'll get back to a bit later in this instructable.







STEP 3: Selecting materials and components.

The next step is selecting materials and components for the phone glove. I experimented with a few different fabrication techniques for the actual structure of the glove, including cutting sheet metal by hand, and using a CnC mill to cut patterns out of a sheet of copper.  While I love working with metal, these tests looked a bit too much like medieval armor, rather than cyborg/robot armor. 



After doing a bit of research I discovered that the Mk. IV and Mk. V armor gloves from Iron Man 2 were actually 3D Printed. 


This helped me decide that 3D-printing technology would be my best bet for achieving the futuristic look I was after, and would also simplify the process of integrating the circuit and components into the design.  I'll get into that more in the 'Step 5: Digital fabrication'.

As for components, I first needed to find a cell phone to hack.  I asked everyone I knew to donate their old phones for the project (most people have at least two or three lying around) so I could begin taking them apart to find the perfect fit.  The shape and functionality of the phone glove will depend directly on the phone you choose, so this is a crucial step!


I went through close to 100 phones, and wasn't quite happy with any of them. Then I stumbled onto a phone online called the Burg Watch Phone, which was just perfect for the project.  It was small, had tactile buttons, and had the perfect functionality for what I wanted this prototype to do.


I decided to re-use the plastic button-caps from this phone (saving me the hassle of fabricating my own.)  I'd also use the battery, speaker, and microphone.  This means anyone who wants to try this build only needs to worry about getting their hands on this one phone, rather than chasing down components from a bunch of different models.



Other components including surface-mount button switches, tiny extension springs, and micro-bolts were ordered from amazon, digikey, and microfasteners.com.




STEP 4: Drawing the virtual model.

To create a design to be 3D-printed, I needed to use some kind of 3D-Modeling software.  I had dabbled a bit with software like Maya and Modo in the past, which is primarily used for creating 3D graphics and animations.  To build a virtual model for this project, I'd need to learn a CAD modeling environment.  This is the kind of software engineers use to design machines, electronics, and other functional devices.  There's a wide variety of software packages to pick from, including programs like AutoCad, Pro-Engineer, Rhino, or Solidworks.  I ended up using Solidworks, as it was available at the computer lab at school.  These programs are often pretty expensive, but if you don't have access to any there is also free-to-use 3D Modeling/CAD software like Blender, Google Sketchup, or AutoDesk 123D.

The next step in creating the virtual model, now that I had selected the CAD software, is drawing each of the parts.  I began by "digitizing" the paper prototype of the glove.  Using a digital caliper, which is a handy little device for quickly and accurately measuring dimensions and angles, I input the geometry of my paper model into digital part files on the computer.  CAD software allows you to use actual units of measurement to define the parameters of the model - I used inches for this model.


I started by drawing the geometry of the top and bottom of the paper finger, then did a lofted extrusion between the two drawings. 


After modeling the basic shapes, I used a feature called "shell" to hollow them, extruded cuts to shape them, and "fillets" to round corners and smooth surfaces.

Really starting to look like futuristic armor now!

I did the exact same thing for the phone circuit, hardware, and electrical components, using the caliper to measure and recreate the objects on the computer.  Having virtual models of these would make integrating them into the design much easier.  I also created a couple of parts that would be cut out of sheet metal on a CNC mill. 



After these extra components were modeled, I pulled measurements and geometry from them to add "housings" onto the structure of the glove.



Like I did with the first paper prototype, I decided to create only one glove finger, and alter copies of it for the rest of the fingers.  Because the external components all need to fit the same way, I couldn't simply scale or resize the model like I did with the paper pattern.  Instead, I had to design a "parametric" model of the finger. Essentially this means the model has a few root dimensions that determine its size and shape, but any part that houses components or hardware stays the same.  Here's a video to demonstrate how these parametric components work:

To make sure the model would fit my hand, I added a simple reference image of my hand to the CAD model.  I traced my hand onto a piece of paper, and drew next to it a one-inch line so I could properly scale the image.  Then, I adjusted the root dimensions of the parametric models until each part of the glove fit…. like a glove!



A benefit of designing the fingers this way is that the glove could be easily modified to fit hands of different sizes.  I tried to simply the model so that anyone can easily edit it by putting in their own dimensions for the width and length of each finger segment.


Along with the STL files of the glove I printed for myself, I've uploaded solidworks files to be modified and scaled, so that one parametric model fits all!  Here's a video that explains how you would go about doing this:



As a demonstration of this functionality, I made a virtual version of the glove for my girlfriend.  We traced her hand, and took a picture of the tracing with a cheap point-and-shoot digital camera. 


Without having to re-draw a model from scratch, I was able to quickly create for her a custom-fit Glove One virtual model, the same way I adjusted the glove to fit my own hand.  Here are the two different models (hers and mine) side by side for comparison:


So if you have some basic understanding of how to use Solidworks, you could quickly customize your own Glove One CAD model.  Keep in mind that the parametric fingers aren't perfect.  Occasionally when you change the root dimensions, a feature or two will bug out and have to be adjusted.  But the basic geometry is there, and I'd encourage anyone to give a go at creating their own, personalized Glove One model!

    
STEP 5: Digital fabrication.

Now that I had made virtual models of all my Glove One components, it was time to begin fabrication!  There were a couple different technologies involved in fabricating each part.

The 3D-printed components include two "plates" for the back of the hand -these house the cell phone circuit and battery - and the finger segments - these house the buttons for dialing the phone as well as the phone's microphone and speaker.  Because I do not have access to a high-resolution 3D printer, I outsourced these components.  There are several different companies that offer custom one-off 3D prints.  I went with Ponoko, and opted for their "Superfine Durable Plastic" option.  These were printed on an Objet Connex 3D-printer, using a proprietary ABS plastic-like material that is cured using UV lasers.  Ponoko was great to work with, and even offered me advice on improving my designs to work better with their printing processes.


Opening a package from Ponoko has got to be one of the best feelings.  Here's what my Glove One print looked like fresh out of the box:


For some other components, like the metal plates that fit over the finger buttons, I used a desktop CNC mill to machine shapes out of sheet metal.  A good friend and mentor Frankie Flood - check out his amazing work here - let me use some of his equipment to fabricate these components.  If you don't have access to a CNC mill, Ponoko also offers services for cutting custom designs out of stainless steel sheet metal.



I also used a laser-cutter to create the back cover which holds the circuit and wires in the upper hand plate:


For 3D prints, you need to save your CAD models as STL files (stereolithography format).  This is a simplified geometric model that 3D-printing software can cut into many little slices to be printed.

The 2D components can be saved in several formats depending on the technology your using to cut them out, like DXF or DWG cad files, or even adobe illustrator files.

The last component to fabricate was the backlit "hand logo" for the back of the hand plate.  There were already LEDs on the phone's circuit, so I wanted to utilize them to make an illuminated Glove One logo, much like the apple logo on a macbook computer. 


For this, I machined an extra hand logo out of a thicker piece of aluminum, and using a scrap of PETG plastic (leftover from another project) I created a little heat-formed embossment to place under the sheet-metal logo.  It was as simple as taping the plastic over the aluminum die, softening it up with a heat gun, and using a piece of craft foam to push the softened PETG into the die.  Instant fancy button-thingie!









The rest of the components are either ordered online, or come from the cell phone I hacked apart.  Now that I have all the parts of the glove (the 3D prints from Ponoko, the flat metal parts cut from sheet metal, the laser-cut cover for the hand-plate, and all the extra bits of electronics and hardware) it is time to make everything look pretty before final assembly.


STEP 6: Painting and finishing.

I wanted the glove to have a shiny plastic look about it (like a modern cell phone would).  Right out of the printer, the plastic parts of the glove started out a lime green color, and looked a bit rougher than I liked.  So I decided to sand and paint each part.

I used a kind of spray-paint by Krylon that is formulated specifically for bonding to plastic.


To paint, I created a little jig, using wooden dowels and re-usable poster adhesive to hold each piece in place while I painted them.



I also created little vinyl masks to protect the housings for the electronics.  I was afraid these would get clogged with paint otherwise.  I used my cheapo vinyl plotter to create these masks, but you could just as well cut them by hand out of masking tape.


One they were masked and mounted, I began by painting all of the pieces in a color (bright blue) that I could differentiate from the final color (black).


Here you can see that a lot of sanding will be required to make the finish shiny and smooth:



After this first base coat, I began wet sanding.  I used 600, 800, and 1200-grit sandpaper for the different steps of sanding.  For wet sanding, I like to use a non-toxic general cleaning agent (method all-purpose cleaner.)




Be prepared to repeat this process (paint, sand, paint, sand, paint!) several times to get a nice finish.


Also, get used to your hands looking like this:


After 4 or 5 cycles of sanding and painting, I ended up with a finish like this:




Good enough for me.  Now it's time for wiring!



STEP 7: Wiring the glove.

I began wiring the glove by selecting the type of wire.  I tested a lot of different kinds of wire, and ended up settling on headphone wire.  Yes, like the wire in your favorite pair of ear-buds.  This wire is ideal for a few reasons:  It is flexible, low profile, durable, and each strand of wire is individually insulated.  It is a bit harder to solder because of the insulating coating, but is worth it in the end to have wires that aren't super bulky and that won't break on you. 



Luckily, the cell phone I used for this build came along with an external headset that contained more than enough wire for the entire glove.


I began by cutting lengths of wire and tinning the ends of each.  This makes soldering them to components much easier. Like I said, soldering this wire can be tricky because of the insulative membrane, so here's a video of how I deal with it:


After tinning the wires, I soldered two wires to each switch.



I did the same for the microphone and speaker.


Then, I placed the buttons, mic, and speaker in the housings of the glove.




I used plasti-dip to secure the wires to the insides of the fingers.  I temporarily held the wires down with pieces of electrical tape, and used a paint brush to apply the plasti-dip over them.  The plast-dip keeps the wires neat and tidy, and protects and insulates them at the same time. 




I also used this stuff to secure the speaker in place inside the distal thumb segment:


As I secured the wires with plasti-dip, I began snapping the finger segments together.  Here is a video that demonstrates the glove's snap-together construction:



After all the wires were soldered to the components and held in place with plasti-dip, I used a multi-meter to make sure all of the buttons were working correctly.  Better to know now rather than later if I have to re-wire a finger.


All the buttons checked out, so I soldered the other ends of the wires to the phone's circuit board.  So I wouldn't get mixed up, I first labeled each copper contact with it's corresponding number.


I started by putting little solder blobs on each contact, then sunk the tinned wire ends into the blobs:





I soldered another wire to the antennae contact, and soldered that to a small piece of copper foil.  This bit will serve as the phone's antennae.



I used some heat-shrink tube to tidy up the wires.  Here's how the inside of the phone looked when the wiring was finished.


And with the laser-cut cover in place:


The last bit of wiring was hooking the battery back up to the cell-phone circuit.  I used the same headphone wire for this, making sure to solder the POSITIVE and NEGATIVE wires to the correct leads.  These are already labeled with a (+) and (-) on the board, so it wasn't hard to get it right.

STEP 8: Final Assembly.

Now the only thing left to do was attach the last few components, and mount the fingers to the base of the glove via the extension springs and micro-bolts.  First, I placed the button-caps into the housings, on top of the tactile switches.  I used a fast-setting epoxy called "Zap-a-gap" to secure the sheet metal covers on top of the housings. 




Before glueing the metal covers in place, I scratched them up a bit with an exacto blade, to help the epoxy adhere to the metal.



Here's a video demonstrating the button assemblies of each finger segment:



To attach the fingers to the hand plates via the tiny extensions springs, I used some dental floss to pull the tiny springs through the mounting holes on the 3D-printed pieces:




Finally, I used a tweezers to hold the micro-nuts in place while I screwed the micro-bolts into them through the loops of the extension springs:



Now that everything is snapped, soldered, bolted, and epoxied in place, it's time to take this thing on a test drive!







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