• Project One: The Steampunk Tesla Cane lives!

    It’s alive!

    At long last, Version 1 of my Steampunk Tesla cane is done, just in time for the Wild Wild West Steampunk Convention!

    Steampunk Tesla Cane!
    Steampunk Tesla Cane!

    The original idea of using a Plasma Ball never really went anywhere, and when I saw another cane made by Der Geis while googling around, I decided to change directions a bit…

    For my cane, the upper cane body is made of Delrin, a plastic that is easily machined, made by a friend of mine who is an expect machinist and uses a lathe and Delrin for making many parts. The stuff is very easy to work with, but doesn’t accept paint well, so its still black, but it does look a bit rubbery, so that fits with the electrical theme. A future redo may use wood or some other material, but Delrin was an easy and fast prototype material. The entire section is held together by hex key screws so I could disassemble and change things around. Oddly enough, the hex key (Allen key) isn’t widely outside of “period” for Steampunk, having been developed around 1910! Future versions won’t need this flexibility, so I may redo the head in wood, or maybe not… The tubes are held in place by grease fittings called “zerks” that are used for greasing some engines, and I borrowed the idea from Der Geis’s cane. My friend also custom made the brass insert from round stock, as well as the aluminum end cap. The interior of the handle is hollow, houses the electronics and batteries, and is wrapped in leather cord for a grip and a sword-like appearance.

    Cane top
    Cane top
    Chamber closeup
    Chamber closeup

    The shaft of the cane is a wood dowel from another project, wrapped with twisted brass wire, and secured to the chamber of the cane with two more grease zerks, one for each wire. The twisting was done using a pair of safety wire twisting pliers. These are special pliers that are designed to twist wire together for safety links or jewelry. I love the look! Just google around for the “safety wire twisting pliers” and you’ll find them.

    Now to the insides! The light tube is the body of a “lightsaber” keychain, just like the one cane I’m pseduo-copying, but I didn’t just use the whole thing like he did. I removed everything but the plastic light tube, supplying my own blue LED. I built a custom circuit using an ATTiny85 (I describe that here) and googled around for interesting affects I could make. That boiled down to two: I could pulse the LED on/off or I could use a “flickering candle” style. I posted a poll (here) and the overwhelming result was the flickering…I agree, it looks like its working, but just barely…very Steampunk!

    Here is the entire circuit: the ATTiny85 in a socket for easy programming, the battery pack (3 AAA batteries in a round holder stolen from a $2 flashlight), a resistor, and the LED, heatshrinked into the end of the lighttube. The LED uses about 20mw of power and I get 1000mw from the batteries at around 4.5v…I left it running for 24 hours as a burn in and the batteries are still pretty full! I did not put in an on/off switch, as I didn’t have one that fit well, that’s for a future version.

    The guts photo
    The guts photo

    I don’t have a great video of the cane running in the completed form, but the effect is clear in this prototype video I made for my friend who worked the Delrin for me:


  • Miniaturizing projects: the ATTiny85!

    A couple of the projects I’m working on will require very small electronics that still need some sort of microcontroller to do something smart, like pulse an LED, respond to a button press, etc…For larger things, I’m using the Arduino series of microcontroller boards, powered by the Atmel AVR MCU (MicroController Unit), but often the final project is to be embedded in something, like a cane, visor, or prop gun, and a full sized Arduino board is too large, even the smaller ones, like the nano, and too expensive ($30+ ) for a complete board…and they are probably overkill for what you need, having far more pins (inputs/outputs) and unnecessary parts (like headers, onboard LEDs, etc.)

    I happened across a Make Magazine article called “How-To: Shrinkify your Arduino Projects” that describes using Atmel’s ATtiny AVR chips, which are a much smaller (8 or 16 pin) and much cheaper (I got mine for less than $1 each on ebay) version of the brain of the Arduino, the ATMega328. You have less pins (2 digital, 3 analog on the 8-pin ATTiny8x series) but the darned thing is tiny, the size of my pinkie fingernail! Note that you could do this with the larger and more expensive ATmega chips, but if all you need is a simple microprocessor, the ATtiny is pretty awesome!

    The Make Article references a post from “High-Low Tech”, an MIT Research Group. The article has since been updated to reflect the support in the newest Arduino IDE (1.03 as of this post) and describes how to wire up the ATtiny to the Arduino and program it via the Arduino IDE.

    To program the ATtinys, you need an Arduino to serve as the programmer and you either wire up via breadboard the ATTiny or use an Arduino Shield for it. I got a shield from a Turkish Company, Flytron, for $20, that does both the 8 and 16 pin variants. After the Make article, lots of companies are making shields and programmers for the ATtiny platform (Sparkfun and Adafruit being the two most common and popular, but they are also all over ebay.) I do wish the shield I got had a ZIF (Zero Insertion Force) socket, as the pins bend easily taking the chip in and out, but other than that, its a nice little shield!

    So, without further ado, here is my first programmed Atmel ATtiny85, running the Arduino LED Fade sketch! Its currently powered from a full Arduino board just for convenience, but sans battery the entire setup is smaller than the 2″x1″ breadboard its running on!

    [youtube]HvaMM4bh2hU[/youtube]

     


  • Steampunk Hat: v1.5!

    I’ve been really pleased with my Steampunk Top Hat so far, but it really needed to have ventilation holes in the front and back as well, not only for Aesthetic Reasons but for airflow.

    New front and back gear shaped pieces, with and without mesh
    New front and back gear shaped pieces, with and without mesh

    I had a good friend who does amazing leatherwork make me gear-shaped gaskets for the front and back to add some pinache, and I dyed them the same dark brown as the other gaskets, shown here prior to installation with and without the brass mesh:

    Installed gear shaped gasket
    Installed gear shaped gasket

    I’m really happy with the final results!

    Front View, completed Top Hat, v1.5!
    Front View, completed Top Hat, v1.5!
    Side View, completed Top Hat, v1.5!
    Side View, completed Top Hat, v1.5!
    The Artist Wife and I at the Steampunk Masquerade Ball
    The Artist Wife and I at the Steampunk Masquerade Ball

  • Playing with analog meters update: video with some code

    After getting the analog meter up and running last time I took the standard Arduino “Fade” example and modified it to make sense with a meter instead of an LED.

    I modified the “fade” sketch with more variables (for easy alteration) and playing around with quite a few settings. I added variables for the initial needle position on the gauge, how far to swing the needle and how fast to swing the needle. I also added some minor logic to derive maximum/minimum swing values for ease of alteration.

    I found that swinging the needle about 10 points (out of 255) to either side of the initial value (so a “sweep” of 20, or just under 10% the total available distance) at a speed of 15 gave a pretty good “jitter” effect:

    [youtube]vJsEQNY7l1o[/youtube]

    The code I made is below if anyone is vaguely interested or would like to laugh at my programming skills.

    [codebox 1]

     


  • Playing with analog meters

    For an upcoming Steampunk/Electronics project, I want to use an analog meter and an Arduino. My idea is to use the PWM (Pulse Width Modulation) feature of an Arduino to swing the analog gauge around.

    Digging around on Google, I found a site that describes using an Analog Gauge with an Arduino and gives me the key information I need, which is that you need an inline resistor to change the 5V generated by the Arduino into whatever the Analog Gauge is calibrated to. The small gauges I got via ebay were a 0-50uA (microamps) and a 0-1mA (milliamps), so I’d definately need a resistor. The article above happens to use a 0-1ma meter like one of the two I bought, so I knew I’d need a 4.7k resistor for it. Using a convenient online Ohm’s Law Calculator I found that for the uA meter, I’d need a 100k resistor.

    I breadboarded up the setup — its very easy: connect Arduino digital pin capable of PWM to the proper sized resistor and then to the plus side of the meter, and the negative side of the meter to ground. I used the standard Arduino Fading LED Tutorial to make the analog dial swing, here is the rough result with to 0-1uA meter:

    [youtube]ZilBQzy0UWw[/youtube]

     

    The next step will be to write an Arduino sketch that sets the meter to a somewhat random value and “bounces” around that value for some dramatic effect. I may also include a potentiometer (a variable resistor) so I can use a dial to “tune” the analog meter in the final project.


  • Helping a friend with cosplay

    A great friend of mine is going to PAX West as EDI, a character from Bioware’s Mass Effect 3. I helped her with the LEDs to illuminate the visor.

    I was originally planning on deadbugging the whole thing — no circuit board at all, just inline splices, but the friendly EE at work told me it would make much more sense to use a perfboard, and would make things much easier. Boy, was he right!

    The setup has 6 LEDs: 3 on each side, each with its own resistor, because I needed to keep the battery weight low (3 AAA). If I could have gone with higher voltage, I could have used fewer resistors, but this worked out pretty well. I used the LED Series/Parallel Array Wizard to calculate the resistor sizes, based on the info off the flat 3mm orange LEDs I got from ebay.

    Here is what I did:

    For wiring, I used cat 5e ethernet cable, which has 4 pairs of wires: each pair consists of a color coded set, one solid, one striped, that are twisted together (hence, ethernet cable being called “twisted pair.”) I trimmed the pair I wasn’t using close to the outer plastic shield and used the other 6 wires, 2 wires for each LED, one cable for each side of the visor. I stripped the cable down to the individual wires at each end for soldering.

    I got a tiny (1.75″ square) perfboard from Radio Shack (again thanks to the EE for the suggestion) and soldered the 6 47Ohm resistors a few pegs from the edge of the board. Where the resistors would attach to the negative battery lead, I soldered all 6 resistors together in a huge blob. I then soldered the solid-colored wires (3 from each cable) near the edge of the board, and connected each solid wire to its own resistor.

    The striped wires I cut longer and soldered in a line near the other side of the perfboard. These also got soldered together in a blob and connected to the positive lead from the battery.

    Perfboard bottom
    Perfboard bottom
    Perfboard top
    Perfboard top with the positive and negative battery leads attached

    The LEDs themselves were a bit more of a pain, partially because I was extra nervous about making sure I didn’t accidently connect the positive lead to the negative supply. Originally I just tried straight soldering the LED lead to the ethernet wire but things kept moving around, so I made a little loop on each wire and lead and hooked the two together, making a really solid mechanical connection. This worked much better, but I kept forgetting to take into account the longer positive lead, so I kept making a little loop of ethernet wire for the positive side to take up the extra space. At each step (individual soldered wire and each LED) I used heatshrink tubing to make sure everything was together as solidly as I could.

    Soldering LEDs up close
    Soldering LEDs up close
    Lights!
    Lights!

    After testing, I covered the entire perfboard (front and back) with a ton of hotglue. Again, this was a suggestion from the EE, as it provides not only insulation for the components but some strain relief for the cabling. I used about 3 sticks! After I hotglued everything, I grabbed a small piece of foamcore that The Artist Wife was using for a project of hers and cut it to slightly larger than the perfboard and put it on the back (to further protect the solder traces) — the hotglue was tacky at this stage so it stuck nicely. Finally, I cut a piece of 1.5″ shrink tube to size and shrunk it on. I wanted to be sure that none of the components could possibly short out due to sweating in the helmet, and to provide as much protection and strain relief for the cabling as possible.

    Protected perfboard and battery pack
    Protected perfboard and battery pack
    Complete Rig
    Complete Rig

    I’m pretty happy with how things turned out, and I learned quite a bit: I’ll be using perfboard for more projects, and I need to be more aware of the difference in the lead lengths (positive vs negative).

    I hope my friend is happy!


  • First real electronics project done: a mintyboost!

    I just finished building a “Mintyboost” kit — its a tiny little cell phone charger that fits in an Altoids gum tin, and charges your phone from a pair of AA batteries. It comes as a kit: all the parts and a printed circuit board for about $20, and it took me about 90 minutes including fixing my mis-soldered part, probably an 45-60 minutes if I hadn’t messed that up.

    I didn’t do half bad! My soldering improved as I went, but I did have one part I soldered in the wrong place, and removing that was a pain! I need to get some solder wick to fix that.

    Completed back of circuit board
    My first soldered circuit board
    Completed front
    Completed front

    Fully installed in the tin:

    Ready to boost!
    Ready to boost!

    The “business end” — I covered the cuts I made in the tin with electrical tape to protect from the sharp edges.

    USB end
    USB end – plug in your cable and you are ready to go!

    And lastly, proof it works!

    Its alive and charging!
    Its alive and charging!