Getting Started with the Arduino (for absolute beginners)

If you’ve been stuck, frustrated or don’t know where to start on your tinkering adventures with the Arduino series, there is a wonderful introductory video series by Martin Lorton which guides you through the board itself as well as setting it up to talk to your computer and some basic programming concepts.

Note: These are slow and steady, meant for people with patience, but they are great for those willing to learn (more importantly, willing to learn how to learn). Some concepts may be redundant for those already familiar with programming.

You can find more tutorials and fun projects on his site.



A video game style electromagnetic gun (from 1934)

So you think your video game has a railgun (or maybe a coilgun) from Doom, Quake, Mass Effect or what have you, that will defeat any armor and is incomprehensibly cool. Alas, it’s made of pixels.

Well, Virgil Rigsby from San Augustine Texas patented in 1934 what he called an “electric gun” – an apt description.

Via modernmechanix.com

Via modernmechanix.com

Mr. Rigsby next to a mockup of his "electric machine gun" (Via davidszondy.com). How badass looking is that?

Mr. Rigsby next to a mockup of his “electric gun” (via davidszondy.com).
How badass looking is that? The pith helmet he’s wearing makes it even better.

Mounted on the deck of a ship or on the back of a truck (if it had a nuclear reactor supplying power), this would have been formidable weapon.

Mounted on the deck of a ship or on the back of a truck (if it had a nuclear reactor supplying power), this would have been formidable weapon.

Bolts. I love bolts.

The premise behind this is that it’s essentially a coilgun with relatively fast reload time (even in those days, EM guns took a while to “recharge”) and rather than relying on complex triggering circuitry which would have been impractical in a time before the silicon chip, he went with a triggering wheel.

Coilguns frequently are confused with Railguns, however the principles of operation are very different. Although they both work on electromagnetism and require a vast amount of power, in a railgun, there are no coils per-se. The projectile/armature and the two rails on either side create one giant electromagnet. Whereas in a coilgun, each coil is an electromagnet momentarily energized sequentially as the projectile gets near each one.

This requires coilguns to be more complex, with multiple stages of acceleration that require intricate triggering mechanisms and careful timing. Therefore, coilguns are more awesome.

This schematic shows how each coil is arranged to be energized in sequence as the arm in the triggering wheel rotates. Note how each coil becomes smaller in width.

This schematic shows how each coil is arranged to be energized in sequence as the arm in the triggering wheel rotates. Note how each coil becomes smaller in width.

As the projectile gets near the next coil in sequence, it is energized. As the projectile enters the coil, it is de-energized and the next coil is triggered, pulling it through the barrel in this fashion until it exits the gun at tremendous velocity. Because the time the projectile spends in each coil is shorter and shorter as it accelerates, Mr. Rigsby wisely chose to reduce the width of each subsequent coil in the barrel.

Detail of the triggering wheel shows how the surface area of each contact plate in sequence becomes smaller as the amount of time the projectile spends in each coil becomes shorter. This is low tech timing in the days before advanced triggering circuitry.

Detail of the triggering wheel shows how the surface area of each contact plate in sequence becomes smaller as the amount of time the projectile spends in each coil becomes shorter. This is low-tech timing in the days before advanced triggering circuitry.

These days, coilguns employ a bank of High Voltage capacitors powering each coil. Modern circuits may also employ a second coil next to the acceleration coil, essentially to function as a simple metal-detector, to trigger the next acceleration coil in the sequence. Some advanced designs may use hall-effect sensors or an optical trigger that fires when the projectile breaks a laser/IR beam between the source and sensor. The optical triggers require slots to be cut into the barrel or often use barrels made of transparent borosilicate glass which is resistant to high temperatures and stress, while still being reasonably permeable to an electromagnetic field.

The biggest downside to this design (besides looking too awesome in front of the enemy, thereby ending the fight before it begins) was that it would have required a monumental amount of electricity to fire each round. These projectiles aren’t paper weights so they required a corresponding level of power at very high amps for each coil multiplied by each time fired. Due to inefficiencies of conversion from electromagnetic energy to kinetic energy, there will also be a lot of heat produced in the coils and triggering mechanisms.

That said… I’m totally building one of these when I have time.

Site of the Week: BioLite

Ever think to yourself, “if only I could power my USB device by burning wood”?

BioLite Campstove. Power your devices with fire!

If you need to charge your USB device, but don’t want to rely on nasty nuclear or ugly coal that’s powering your house (if you’re not already on solar), then BioLite has the stove to do it. By burning leaves, twigs or what have you, never run out of power.

At first, I thought this was a joke, but it turns out to be a totally serious product. For $129, you get a stove, according to the product page that is able to :

Charge your gadgets
By converting heat from the fire into usable electricity, our stoves will recharge your phones, lights and other gadgets while you cook dinner. Unlike solar, BioLite CampStove is a true on-demand source.

But the real appeal of this is that it needs :

No fuel to buy or carry
Our stoves cook your meals with nothing but the twigs you collect on your journey, eliminating the need for heavy, expensive, polluting petroleum gas. Quick to light, fast to boil and easy to use.

Of course, there are backpack USB chargers in the market these days, but they don’t work well when it’s cloudy and not at all at night. Presumably, these probably won’t work as well when it’s raining unless you’re in a shelter with plenty of ventilation for the smoke, but you can still charge outside when dry, day or night. I’m not sure how eco-friendly it really is since you’re still burning fuel, but I imagine it’s a lot less than the several tons of CO2 expelled by your local coal power plant.

Check out the product promo :

Storage score: The Telephone

Specifically it’s a Model 2500 made in the 1980’s!

I don’t know why, but things like these have always fascinated me. I’ve always had a soft spot for classic electronics and gadgets (some so heavy, you could also use them to repel burglers), but phones in particular have been top on the list. The manufacturer, Comdial, is now bankrupt although they’ve been making phones since October 1982. So the phone could be older than I am. Unfortunately I couldn’t find any dates for reference.

I actually got this phone a few years ago for a short film; the screenplay I wrote, WHICH SHALL NEVER SEE THE LIGHT OF DAY, called for the number 216 on the label. 6 * 6 * 6 = 216… Yeah, this was totally a B-movie.

I don’t remember if I got it at a yard sale or in the trash. Either way, after spending a few more years in storage, it’s finally home!

When I finally build my little cabin, I’m having this connected as soon as the phone lines get hooked up. It would totally match the rest of the retro feel I’m going for.

Behold, the magnificient obsolescence!

 

Brand, Comdial

 

Looks like it's had a few battle scars over the years.

 

Don't see a lot of those anymore!

 

Of course I took it apart! That's why things are there... To be taken apart.

 

So many wires... so tappable. Not that I've ever done that.

 

Off hook

 

On hook

 

The Telephone

DIY Hi-Fi Loudspeaker

It’s projects like this that make me all warm and fuzzy on the inside.

It's even more cool in person

It's even more awesome in person.

José Pino describes in detail how to build a loudspeaker from :

  • 1 Magnet
  • 1 Business card (Please make sure it’s expired or cancelled first)
  • Wire 32 or 34 AWG
  • Paper bond
  • Tape
  • Glue
  • Scissors
  • Ballpoint pen
  • Lego bricks or wood.
  • Ruler.

This reminds me of an old dream I had of a DIY, steampunk, radio project. I think this guy just inspired me to take it up again.

Update 10/01/08

The link and image shown are actually for his original speaker design. The Hi-Fi speaker is actually a different page.