The Triptych - a Portable Arduino Workshop

by NEIN in Workshop > Organizing

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The Triptych - a Portable Arduino Workshop

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trip·tych [trip-tik]

noun

  1. Fine Arts. a set of three panels or compartments side by side, bearing pictures, carvings, or the like.
  2. a hinged, three-leaved tablet, written on, in ancient times, with a stylus.

In this project, we'll be building the Triptych, a portable Arduino workshop. It's a self-contained, portable (Trip, get it?) solder station, Arduino workstation (through the Arduino IDE running on the Raspberry Pi), and configurable parts storage. As the name suggests, it's made in three parts, with the left and right sides folding open to reveal the workstation inside. Check out this short video.

There are a few different aspects this Instructable will cover.

  1. Setting up the Raspberry Pi (aka RPi) as a self-contained computer. This includes an HDMI monitor, Bluetooth keyboard, wireless mouse, speakers, and a WiFi dongle.
  2. Setting up the Arduino IDE to run on the RPi. Specifically, how to install the provided ISO image to work with RPi. I've also included some detail about and links if you want to try installing the IDE yourself.
  3. Designing and building the case itself - I'll provide the DXF files, but also discuss what tool chain to use to design your own box.
  4. Mounting the RPi and all other required electronics.
  5. Designing and building the stackable shelves
  6. Stocking it with all the goodies required for a basic kit

In most cases, I've tried to provide a shortcut if you just want to build one, as well as some detail if you want to know more about how I built it.

Once again, I used the RedSail 80watt lasercutter from my local hackspace, VHS to cut the parts. If you want to build one quickly, I would recommend buying exactly the same parts that I've used, as the RPi image is built for this setup. Of course, if you want to experiment, go for it!

Footnote: Why you should join a hackspace
It used to frustrate me to no end when I would see an awesome Instructable that required some specialized tool like a laser cutter, water jet cutter, 3D printer etc. Having neither the space nor the money for these fancy tools, I would try to to replicate patterns on a scroll saw, or by some other means. Given my lack of actually woodworking skill, that quickly became an exercise in frustration. That's when I started looking around for folks that might actually have these tools and be willing to share and teach. I was turned on to my local hackspace and never looked back. If you're the type of person that enjoys Instructables, I promise you'll find great resources in tools and brains at your local hackspace. If there's no hackspace near you, start one! Trust me, the cool tools will follow.

Parts

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The following parts were used in this build:


Electronics

  • Raspberry Pi (aka RPi) - A or B should be fine ($45.50). Get the new version with the mounting holes if possible.
  • 8gb sd card ($14.97) - I'm using a class 6 card now, but I may upgrade it if speed seems to be the bottleneck
  • Low-profile MicroSD Pi Adapter ($7.00) - Not strictly required, but gives you a few more options about where you can mount the RPi.
  • 10.1" 1200x800 IPS Display from Adafruit ($154.95)
  • Stereo speaker set from Adafruit ($7.50 US) You could use regular portable speakers if you want, but make sure they fit.
  • 12v DC 1000mA power supply for the monitor ($8.95)
  • Wireless mouse ($14.99 on sale)
  • Bluetooth dongle ($15.99)
  • Folding Bluetooth keyboard ($44.99) - something small that will fit in the case.
  • WiFi dongle ($14.99) - make sure you get on that's certified to work with Raspberry Pi
  • Powered USB hub ($34.99) - anything with a small form factor will work
  • Power bar with USB charger ($18.99) - The USB charger must provide at least 1 amp. I love this power bar. The plugs are far enough away so it can take large adapters. It only has four outlets, so it's not overly long, and it has 1 amp USB power supplied too.
  • Laptop with SD Card read/write capabilities - this Instructable will use a Windows 8.1 laptop


Box structure

  • 1/4" baltic birch plywood - 5'x5' ($25.00) For the outer case and the monitor mount
  • 1/8" baltic birch plywood - 2 1/2' x 2 1/2' ($9.00) For the drawer and the monitor mount
  • Piano hinge - 1 1/16" X 36" ($11.50)I got the antique brass finish
  • Wood screws 3/8" #6 brass screws ($5.50 for 100)- Small but mighty. I did some tests with this as I was a bit concerned about strength, but because there are so many of them, they hold fine.
  • 2" Surface door bolt ($13.40) - to keep the box closed!
  • Roll of velcro ($8.96) - cable management
  • Stickback velcro ($4.47) - to secure the smaller electronics (speaker, USB hub) to the case
  • Rubber adhesive feet


Internal storage

  • 3mm acrylic sheet - ($11.20 each for 24" x 48" sheets) (depending on the types of boxes you want - the larger boxes use more acrylic, since there is more waste). I found all my acrylic at a craft store that sells off cuts. It cost me about $20.
  • Methylene Chloride aka Acrylic Adhesive - ($9.99) 4 oz
  • Applicator ($6.25) - this is really required for welding acrylic
  • 1mm Elastic Chord x 4 metres ($1.99)


Carrying harness

  • 4 metres of 1" webbing ($1.00 / metre)
  • Quick Slip® Keepers ($0.50) x 4
  • Cam Buckles ($0.90) x 2
  • 4 Way Crossover ($0.76) x 4
  • Slides ($0.25) x 4

    Parts storage
    • Glitter mixing tubes - ($8.99 for 2 packs of 6) I got mine at Michaels, but I can't find them on their website.

    Tools

    For the outer box, monitor mount, drawer, and internal storage, I cut the parts using an 80 watt laser cutter. If you have a bit of experience with woodworking, you can probably modify this design and replicate it by hand.

    • Screwdrivers
    • Palm sander with 220 grit sandpaper
    • Hacksaw to cut the piano hinge
    • Metal file to smooth out the hinge edges
    • Wood glue
    • Drill to mount the electronics
    • Dremel for various work on the project (trimming bolts, drilling holes, etc).
  • Setting Up the Raspberry Pi

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    This part is pretty straight forward. We need to load the disk image on to the SD card. This will act as the operating system for the RPi. You can not just copy a file to an SD card and use it in an RPi. Rather, you must load an .iso image to the 8gb SD card using software called Win32DiskImager.

    Downloads!

    Download and install Win32DiskImager from SourceForge.net. You may need to run the installer as Admin.

    Download this Triptych1.0.rar iso (1.2gb) that I've already built. I don't typically like using for-pay software for compression, but the file was too large to be compressed by Windows.

    It is based on Raspbian Wheezy, and uses the standard username: pi Password: raspberry. It is configured to use the 10.1" screen from Adafruit. It has the Arduino IDE installed and ready to go. Also the bluetooth tools (for the keyboard) are installed and ready to be configured to connect to your specific keyboard. No installation was required to get the USB wifi dongle or the mouse running.

    It will boot directly into the Raspbian desktop and there will be a shortcut to the Arduino IDE on the desktop.

    Using Win32DiskImager

    The Win32DiskImager software is pretty straight forward. Follow the below steps:

    • Insert the 8gb SD card into your laptop
    • Unizip and browse to the Triptych_1.0.iso file
    • Specify the drive letter of the SD card
    • Click the Write button

    References

    If you would like to build up the RPi yourself, here are some links to help. Make sure you have the wifi set up first. Most of these tutorials require internet connectivity.

    • To set up the wifi, connect the dongle to the RPi and power up. Then launch the wifi tools on the desktop.
    • To install the Arduino IDE on Raspberry Pi yourself, more info is available on Tenet blog.
    • To change the RPi behaviour on startup, see this thread on Stack Exchange.
    • If you would like to use a different monitor, you'll have to edit the config.txt file on the RPi. Check out the R-Pi ConfigurationFile guide at eLinux
    • For installing the Bluetooth tools, see ThinkPenguin. Rather then using su to log in a root, you can always use sudu before each command. For example, another way to install the bluetooth utilities is:
    sudo apt-get update
    sudo apt-get install -y bluetooth bluez-utils blueman

    Testing the Electronics

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    Before we get too far into building the cabinet, let's make sure all our electronics are working properly.

    • Insert the SD Card
    • Connect the USB hub to the RPi
    • Plug the WiFi, mouse and Bluetooth dongles to the USB Hub
    • Connect the monitor to the RPi via the HDMI port. Make sure the monitor is connected to the driver board.
    • Connect the USB hub and the monitor to the power bar
    • Turn on the mouse and keyboard
    • Connect the RPi USB power to the USB port on the power bar
    • Plug the power bar in and turn it on
    • Connect the power to the RPi to a powered USB port

    Set up the bluetooth keyboard

    With everything connected, the first step will be to connect the bluetooth keyboard. The mouse should work right out of the box, and that should be all we need to get the keyboard working.

    1. Turn on the keyboard. The LED should light up on it. Press the connect button on the keyboard
    2. Click the start button
    3. Select Preferences > Bluetooth Manager
    4. Click on Settings > Search
    5. The keyboard should now appear in the list. Add it to your trusted devices.

    Connect to your WiFi network

    This part is straight forward. There is a link on the desktop to the WiFi Manager.

    1. Open the Wifi Manager
    2. Click Scan to find your network
    3. Once it appears in the list, double click it to enter the password

    Test the Arduino IDE

    Now that we have all the peripherals working, we can start the Arduino IDE and see if it recognizes an Arduino.

    With everything working, we just have the simple task of building a case to hold it all!

    Designing and Cutting the Case

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    Case design
    The case is made of a back box (which will hold the monitor, RPi, USB hub and some other electronics), and two front doors connected with piano hinges. There is a simple drawer (no slides) in the bottom of the back box that will hold the keyboard, mouse, and some of the larger tools that are too large to store in the doors. Each door is held on with piano hinges that allow them to swing all the way open. Stacking boxes will fit inside the doors, and will hold tools and various components. The boxes are held in place with elastic chord that runs in the slots from the top to the bottom.

    I've designed several different storage boxes for you to pick from ,depending on what you want to store. Since each door is 400mm tall, all boxes are (slightly less then) multiples of 50mm. For example, there's a 50mm simple box for small components, a 100mm box to store my resistors in the glitter tubes. A 150mm box and a 200mm box for taller tools. Use each of these components in any configuration you like, as long as they add up to 400mm. Elastics hold the boxes in place.

    The case itself is made from 1/4" ply. The drawer in the bottom made from 1/8" ply. The storage boxes can be made from either 3mm acrylic or 1/8" ply. I used acrylic in this Instructable so I can easily see into each box without having to remove it. The lids are held on with elastics.

    The Triptich is carried by a harness that quickly attaches on the underside and around the doors and it's carried messenger bag style. I thought this would be a nice detail while removing any single points of failure that you might get from a single handle.

    I've uploaded a sketchup 2013 file, as well as a 3D PDF (that, for some reason, has wonky textures) if you want to take a look.

    CAD files
    You'll see there are two dxf files above.

    Some points to note:

    1. All my dxf files are 1:1 scale in millimetres. That's how I roll.
    2. The thickness of my plywood was 6.37mm for the 1/4" and 3.15mm for the 1/8"
    3. Unless you have a huge laser cutter, the entire dxf file will not be able to fit on the bed at once.

    Caseplans8.dxf - this should be cut out of the 1/4" plywood. This is the basis for the case. Don't discard any left over ply, as we'll need to cut the monitor frame out later.

    Drawer.dxf - this should be cut from 1/8" plywood. It's the drawer that fits below the shelf in the back. Again, more 1/8" ply is required for the monitor frame.

    What's that? You don't like the size/width/aura of the case? Ok, here's how to make your own.


    Design and build your own!

    Inkscape
    Now that we've confirmed the electronics portions is working, let's start on the case. The case was designed in Inkscape (free!!). I found an extension for it that creates box layouts that can be cut on the laser cutter. The extension is called Tabbed Box Maker, and it's available on a rather non-descript website called Maker (not to be confused with Make).

    Installing Tabbed Box Maker

    Download the BoxMaker.zip from the above link. If you're using Windows, extract the files boxmaker.inx and boxmaker.py to /share/extensions. For me, this was:

    C:\Program Files (x86)\Inkscape\share\extensions

    And though I didn't try this, the Readme.txt says for installation on linux, copy the files to:

    usr/.../Inkscape/share/extensions (NOTE: you need to make boxmaker.py executable)

    Modifying the output

    So now we have the outline of our boxes. One important fact is that the Tabbed Box Maker makes... well, boxes. The process here is to create three boxes (back, left door, and right door). Since we don't want the boxes to be fully enclosed (how would you get in!???!!), you can delete the extra side in Inkscape.

    Also we want flat edges (and NOT tabs) where the back box meets the doors, and where the doors meet each other, you'll have to remove the extra tabs in Inkscape. In this case, remove them to the bottom of the tab. This is because we specified that our box dimensions were inside in Tabbed Box Maker.

    With regards to adding slots in the middle of the box (as we have with our shelf for example), make a copy of the piece that will be inserted - the shelf in this case. Snap the tabbed edge of the shelf in place and use that as a guide to line up the slots.

    A brief discussion on kerf

    In order to get a good solid fit with these types of boxes, it's important to know the kerf of your laser cutter. Kerf is the width of material that is removed by the tool - think the thickness of the line. It's important to know the kerf when building these tabbed boxes. If the pieces are a bit loose, the structure will not be solid. The Tabbed Box Maker takes this into account when laying out the boxes. James at RedToRope has a good explanation, and ways to measure it. Or the quick (less accurate) way is to use this table over at CLC for a rough guide to get you going.

    Tests, tests, and more tests

    Once you have your design and kerf figured out, and you've generated your DXF files, do a test on the actual material you will use. Cut a thin strip of tabs and grooves and see how they fit together. This is particularly important when you will be using two different materials like acrylic and wood.

    Also if you have a professional version of SketchUp (or a demo of the Pro version), you can import DXFs, use the Weld utility to join all the lines and make faces, then extrude each fact to it's actual depth (6.3mm for the box). Then using rotate and move, you can test fit your box together. Hint: If you make components out of each piece, it will be much easier to work with.

    Other considerations

    We need a way to hold the boxes in place when the case is closed. For this, I've decided to use some elastic chord I had left over from another project. You'll notice the top and bottom of the sides have lines cut into them. This is where the elastic will go that will hold the boxes in place. Feel free to modify this or look for another solution.

    Building the Monitor

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    The concept

    We have a limited amount of space to mount all our electronics. Also, the mounts on our monitor are a little flimsy. For these reasons, I decided to design and cut some ply that would support the monitor, while providing a cavity underneath where the monitor electronics can be mounted. This way, the monitor is supported without relying completely on the little metal tabs, and we can get the monitor driver board out of the way.

    The design

    There are seven plates that stack on top of each other to give us a bit of depth under the monitor for the video driver. There are two dxf files.

    Quarter_monitor_mounting_plates.dxf - This file should be cut from 1/4" baltic birch. It includes the

    • Back plate - this is what the the monitor driver and the Options board is mounted to. It's also the part that gets attached to the back of the box.
    • Two regular spacer - these spacers give us the depth we need.
    • One spacer with a cutout for the Options board wire and speaker wire

    Eighth_monitor_mounting_plates.dxf - These thinner spacers are cut from 1/8" baltic birch. There are two plates that go above and below the monitor, and one larger finishing plate that acts as a bezel.

    To assemble

    1. Mount the video driver to the plate 1 with the M3 screws. Don't screw the board down too tight or you risk damage.
    2. Insert the M4 screws through the back of the baseplate into the four mounting hole. They will likely be a little tight, but you should be able to screw them in. Insert them until they are just above flush with the baseplate.
    3. Add plate 2. Hold it tight to plate one and continue to screw in the screws until it's again, just above flush.
    4. Add plate 3. Same deal
    5. Add plate 4. Once plate 4 has been added, but sure to run your Options board cable down through the channel before inserting the first 1/8" spacer.
    6. With the cable in place, add the first 1/8" spacer over top and attach it.
    7. Now the monitor goes in place. It will fit inside the 1/8" spacer and the mounting tabs on the monitor will line up with the screws. Slowly screw the screws into tabs until they protrude just a bit.
    8. Add the second 1/8" spacer on top. Again, it will fit around the monitor. Continue the screws (I missed photographing this step)
    9. Finally, add the bezel. Now apply the nylock locking nuts. If the screws are a bit long as they were in my case, trim them with a dremel.

    And that's how you build a monitor out of wood! Whew!

    Assembling the Case

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    Now we put it all together

    Test fit

    So we've cut the parts for our box. The next step is to make sure there are no issues with our design. If we've calculated the kerf correctly, the pieces should be very snug. Start to fit the pieces of the box, doors, and drawer together. Don't force them all the way in if they don't want to go. We just want to make sure all the tabs line up, the clearance for the shelf is correct, etc. Disassemble when you've confirmed everything fits together, and the drawer will also fit.

    Sanding the parts

    Sometimes the laser can cause burn marks on the plywood. Also, if you've been handling the pieces, you'll notice that the black burnt residue from the edge seems to get everywhere. Before we glue up the cases, we'll run the palm sander over them to get rid of the grime.

    Glue the case

    Once all the parts have been sanded, you can wipe them down and apply the glue. Apply glue with your finger to both pieces. Think of how they will fit together, and only glue the two sides that will make contact. Apply glue to the contact side of the tab and to the slot Try to keep it neat, as the stain won't stick at all to glue. When the glue is on, tap the tabs in place by setting a piece of scrap wood on the work piece and gently hit it with the hammer.

    Clamp the case

    Now clamp the pieces in place with bar clamps. Attach the clamps at the tabs, otherwise it can warp the material. Don't bother clamping the drawer, as 1/8" ply is a little too flexible. If the parts aren't lining up perfectly, try wrapping it in newspaper and taping it tightly. After it's clamped, take a good look to make sure there are no gaps between the joints.

    Finishing

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    More sanding!

    Now that everything has been glued up, we'll run the sander over them one more time to make sure the tabs don't poke out too far.

    Stain

    Believe me when I say I'm no expert, but I've stained a few things in my life. I really like the MinWax Polyshades product. It's a stain with a built-in urethane finish so it can be done in a single step. Make sure you stir it well to get the sediment off the bottom mixed in with the rest. Evenly apply a generous coat, wait a minute or two depending on how dark you want it, then wipe it off with a rag. If you want it darker still, apply a second coat after the first has dried.

    In my case, I stained the drawer, the lattice, and the outside 'Matte Black'. I left the inside natural with a coat of varithane.

    Give it lots of time to dry.

    Finishing Touches on the Case

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    Now that the case is done, we can add the last little bits.

    Hinge

    Let's make sure everything fits together still. Cut the hinge at 14" with the hacksaw. Use the 3/8" screws to attach it. The brass screws are a bit bright for the antique brass finish of the hinge, so touch them up with a bit of the black stain if you want. The brass screws I used have a slot head in them. It will a lot easier to get these in if you drill very small pilot holes first. Depending on the thickness of your plywood, you may have to sand down the ends of the screws if they poke through a bit. I used my dremel to touch them up.

    Harness

    It doesn't really count as mobile if you can't carry it! We need to add a strap. I decided to use 1" webbing. I wanted to design it in a way that there was no undue stress on the case. I decided to build a simple (no sewing required) harness. I used a cam-type closure, but buckles would also work quite well.

    Measure out the webbing so it goes completely around the case with about 5" extra. Cut two pieces this length. Attach the buckles and the cams. Then slide the open end through two of the 4 way crossovers (I just learned what these are called!). The cross overs should be positioned so that when the webbing is wrapped around the Triptych, they are on the ends, straddling the doors and the back. It's clearer to see what I mean in the pictures above. Once the horizontal straps are in place, thread another piece of webbing through both the upper and lower slot lash tabs, underneath the Triptych and up the other side. To connect the two pieces at the top run one strap through a slide, then run the other end through the same slide in the other direction.

    Run any extra webbing through the keepers

    The straps don't have to be cinched super tight to work. The case will stay closed with the latch.

    I think this looks ok, but it would look really sweet if it was done out of leather. Of course then the cam buckle would have to be replaced with something else. Maybe a belt buckle type thing?

    Latch

    Now we need to make sure that we don't lose our gear while we're carrying it. For this, I used a dull brass sliding latch. It's screwed in with 3/8" #4 brass screws. Again, drill some pilot holes to make this easier.

    Feet

    We should add a little something to protect the bottom. I picked up two sets of 8 non-slip stick on feet. Mount four of the feet on the back, and four on each door. You can find these at almost any hardware store.

    Mounting the Electronics

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    Now that the case is completed, we can mount the electronics. I did not include pre-drilled holes in this case design because you might want to use different components, and the hole patterns wouldn't match up. The less holes in a case, the better. For many of the components, I use velcro straps to secure them. This allows them to be easily moved, or replaced completely.

    Test fit everything together

    Start with the monitor. It's the largest piece and can not be obstructed. Once that's in place, set up the power bar. It's the most awkward and will require the most thought. I think there are only two real options, either along the bottom shelf, or along one of the sides. I decided to mount mine to the bottom shelf. From here, you will still have to consider:

    • Where the RPi will go
    • How to deal with the cable from the power bar (where it will exit the case, how it will be stored when the case is closed, etc)
    • Placement of the USB hub
    • Cable management

    Mounting the gear

    Monitor

    Once you have an idea where each component will go, you can drill the holes in the case for the monitor mounts and mount the monitor with bolts. You want it to be tight, but not put any undue stress on the monitor.

    Power Bar

    Next, drill the hole for where the power cord will exit the case. I decided to use a plastic grommet to make the hole a bit neater, but it's not required. This grommet required a 2" hole. For this, I used a hole saw. I drilled a pilot hole with a regular drill bit, then I started with the hole saw. If you drill about halfway through, then flip the case and continue drilling from the outside. This will ensure a nice clean hole on both sides. It was at this point where I noticed that the grommet was about 3/8" too deep for the case. I cut the excess off with a hacksaw and touched it up with sandpaper. I then used silicone to secure the grommet in place. With the hole drilled, I could then screw the velcro straps in place that will hold the power bar.

    Raspberry Pi

    I mounted the RPi to the side of the case. I did pick up an enclosure for it, but I decided not to use it. I thought the benefit of the extra airflow would outweigh the protection of the case. I may change this in the future if required. I was using one of the new RPi's that have the mounting holes. I marked these mounting holes on the case, then drilled them out. I used some small bolts, and aluminum standoffs to attach the RPi. Again, enough pressure to keep it in place, but not enough to damage the board.

    USB Hub

    The USB hub was secured with stickyback velcro directly below the RPi.

    Speakers

    Same deal with the speakers, more stickyback velcro. This allows me to change the position if I don't like the sound. The speakers go above and to the sides of the monitors.

    Cabling

    Now the hard part. Dealing with all of the cables. My default method is to screw more pieces of velcro strap. This is not the stickyback stuff, but the velcro you buy in rolls. Depending on the thickness, you may be able to staple it in place, but in my case, I opted for small screws. Plan carefully, as you'll leave little screw holes as a stark reminder of each poor decision.

    Optional - RPi Power Button

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    Based on one of my other Instructables, I decided that a power button to kill the power to the RPi, without shutting down the power bar or unplugging the USB cable would be a nice touch. Perhaps you want to still solder without having to turn the RPi on.

    I found a great inline switch at Lee's Electronics for $3.50. Once the electronics are all in place, you should have a good idea of how long your RPi power cable needs to be. Add about 2" just in case.

    Then snip the cable, discarding the middle section.

    Remove about an inch of outer casing from each end of the USB cable. Do this by scoring the cable all the way around with an xacto knife. Don't worry about cutting into the small delicate wires underneath, as the USB cable should have a braided sheath

    Remove the foil covering, then remove the braided wire with your clippers (if you twist it first, it will be easier to discard). Once that's done, also remove the white and green wires. These are used for data transmission. We are only using this USB cable to provide power, so we only need red and black.

    Strip the red and black wires back about 1/3" or so. Twist them and connect the red to the side of the switch with the gap in it. The black connects to the side that's continuous.

    Do the same for the other end. Make sure the connection is solid.

    When putting the case back together, make sure the unstripped part of the cable is held in place by the case. Otherwise the cable will not have much strength if it's pulled apart.

    And that will give you a nice little RPi power switch. Remember not to kill the power unless the RPi has been properly shut down.

    I mounted the switch using sticky velcro as well.

    Building the Storage Boxes

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    Now that things are starting to shape up, we can get going on the storage. The concept is that we build the boxes in increments of 50mm (outside dimensions). By standardizing the size, boxes can be swapped out. Need to store some larger components? Replace two 50mm boxes with a 100mm one.

    Design

    I'm a huge fan of Adam Savage (check out his podcast), and one of the concepts he subscribes to is the concept of First Order Retrieve-ability. This means that you should never have to move a tool to get another tool. Well, due to the nature of the Triptych, that's not exactly possible, so I've modified his idea and come up with the next best thing - First Order Viewability* (I totally just made this up). If you can't get the item you need without moving another tool, you should be able to at least see it. This is the main reason I decided to build the boxes out of acrylic. It does add some cost to the project, and acrylic is difficult to work with if you don't have a laser cutter, but there's no reason why you can't build these boxes out of eighth inch plywood. If you're diligent with labeling, it might work just as well.

    Again, all the boxes are in roughly 50mm increments. They are all glued together except for the top piece. The top is held on with two elastics that fit into notches in the top and bottom plates.

    My designs include:

    A large box (150mm) for some of the tools that are a big bigger

    A medium box (100mm) for wire, circuit boards, etc.

    A medium box (100mm) with storage for the glitter tubes that will hold our resistor collection

    A small box (50mm) for smaller components

    A small box (50mm) with long dividers for long and skinny parts like heat shrink, jumper wire, tweezers, pencils, etc.

    A small box (50mm) with small divider for servos, pots, and other small electrical components.

    Building the boxes

    1. Laser cut the attached DXF files. Again, use any combo you want, as long as the total height adds up to 400mm.
    2. Remove any protective backing from the acrylic
    3. Use the methylene chloride in small applicator bottle to weld the joints. Use gloves, and do this in a very well insulated area, as methylene chloride is fairly toxic (see the OSHA sheet). See this video from TAP Plastics if you need a bit more instruction. You won't have to do any sanding on the edges as the laser cutter leaves a perfect edge.

    Stocking the Boxes

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    Some of the things we want to store include:

    Components

    wire, resistors, photo resistors, capacitors, leds, buttons, pots, motors (steppers and servos), switches, jumpers, heat shrink, perf board, headers, battery holders / batteries, screw terminals, audio jacks, various sensors

    Tools

    snippers, solder, solder iron, solder iron tip cleaner, helping hands, mulitmeter, strippers, solder sucker, flux, pin vice, clippers, breadboard, micro screwdrivers, tweezers, leatherman, xacto knife, ruler

    Electronics

    Arduinos, shields (GPS, Audio, motor, protoboards), cables, Keyboard / mouse, other electronic components

    Misc

    Notebook, pencil, LED light.

    And there you have the Triptych!!

    Future Enhancements

    After building the Triptych, there are a few things I would like to test next time:

    1) I'm not crazy about the latch. I think perhaps a draw catch might be better.

    2) I would be interested in maybe trying a case made out of 3/8" ply to determine if the extra weight would be worth it. So far the structure seems really solid, but time will tell.

    3) I'd like to design a better storage case just for wire that feeds it out without having to open it.

    4) I probably could have more glitter tubes in the storage case by making the holes closer.

    5) A wider shoulder strap for the harness might be in the works. Also, I think I'll replace the cam closures with buckles.