A felt IC

Published December 21, 2009 Uncategorized 5 Comments

A felt chip for the other hacker in the household:

At first I thought I’d have to get out the calipers to measure the various dimensions, but turned out there was a nicer solution – the datasheet already has drawings of the chip, drawn to scale. So getting the sewing pattern just becomes a matter of tracing out the datasheet drawings in Inkscape:

The various traced out parts are then scaled to the desired size, and borders then added for the seams. The chip is padded out with a rectangular foam block, and folded-up strips of aluminium foil are used to strengthen the legs.

The next natural improvement would be to actually embed a real OP-07 within, and have conductive threads sewn into the various legs.  But in the absence of conductive threads at home, this is the best that can be done for now.

An interesting observation: If you play with this long enough in a dry room, and then pick up a real OP-07, the latter throws a hissy fit (out of jealousy, no doubt) and releases all its magic smoke. :P

Arduino Tic Tac Toe

Published December 21, 2009 Arduino , circuits , lights , toys Leave a Comment

Build details and code here.

Starting a Mjolnir armour build…

Published November 8, 2009 costuming , lights , papier mache Leave a Comment

But from papier mache!
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Papier Mache Master Chief Helmet – More DIY How To Projects

Flower sticks

Published June 27, 2009 toys Leave a Comment

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One thing great about competitions like this is that you get exposed to all sorts of activities that you never knew existed before. Like stick juggling – it’s quite an interesting physics study in rotational dynamics.

Since a set of juggling sticks isn’t something that you can just get from your nearest supermarket, I thought it might be cool to make a set from scratch. After all, how hard can it be to decorate up a bunch of sticks?

Rather surprisingly, there aren’t that many how-to guides out there about how you actually go about making a set. Here’s three methods I found:

Hockey tape method: Hockey isn’t a common sport around here, but I figured tennis racket tape would work as a substitute. Except that one small roll was about $12, which was a leetle bit more than I was thinking of spending…

Electrical tape method: A variant of the above, but some quick tests showed that electrical tape was too smooth and not grippy enough.

Rubber tube method: Old inner tubes are about as elusive as hockey tape!

Then by chance, I spotted this at a neighbourhood store:

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An anti-slip mat – now that should be grippy enough for a flower stick!

Making a set of flower sticks now becomes ridiculously straightfoward.

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I’ve no idea how suitable this homemade set would be for advanced tricks, but it’s certainly good enough for one to learn the basics, and even spin a propeller or two. :)

SpareShip!

Published May 12, 2009 bots , circuits , junk , lights 32 Comments

A SpareBot-inspired spaceship:

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It’s more fun, of course, when the LEDs actually light up:

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Here’s the circuit diagram – basically three LEDs in parallel, a battery, and a magnetic reed switch:

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A resistor is added to each of the red LED branches; this is to limit the current in those branches so that the white LED gets some current as well. Without the resistors, the bulk of the current will flow in the red LED branches (which have less resistance), and the white LED will not light as the current flow through it will be extremely small.

Since the ship’s just held in place by wires, turning on and off a mechanical switch would eventually flex the ship out of shape. Hence a magnetic reed switch is used, it’s more streamlined and you can hide it in the fuselage without anything sticking out.

Street Lamp

Published May 1, 2009 circuits , lights , origami 2 Comments

Here’s an origami street lamp:
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Here’s an origami street lamp at night:
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It’s folded from two sheets of paper, with some electrical components stuffed in:
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The circuit – bulb, switch and battery in series – fits nicely into the base of the lamp:
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More origami lights coming up in the next few weeks!
(assuming I get around to it, obviously…)

Slipper repair

Published April 9, 2009 fixes 4 Comments

A lot of footwear these days simply have their soles glued on; it’s cheap and fast manufacturing. Except that this glue doesn’t appear to last long over here (we’re guessing it’s due to the extreme humidity levels – we’ve never had a sole drop off in temperate climates). Which leads to the annoying flapping sole problem:
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Using glue just doesn’t work either, no matter how clean the soles are, or what kind of glue you use – superglue, rubber cement, shoe goop…they all last a few days at most. So something sturdier is called for:
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It’s a leather sewing awl, designed to punch through thick leather and canvas, and really, just about anything in a shoe. Using it is relatively easy – it produces a lockstitch (kind of like a sewing machine) that holds whatever you’re sewing together.

First, push the needle through, and pull out a length of cord about twice the length of the edge you intend to stitch up:
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Then, pull the needle back out:
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Push the needle through again, just slightly away from the first point:
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Pull the needle back just slightly, and a loop will form between the eye of the needle and the punched-through point:
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Thread the long free end (what you pulled out at the very first step) through the loop:
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Pull back the needle fully, and pull on both ends of the thread to tighten:
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And that completes one stitch! Now, just keep repeating the stitching step around the edges you want to stitch up. When you’re done, simply snip off the thread at the needle, but leave a few centimeters:
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Tie off the ends with knots, and cut off the excess. Here’s how the fixed sole looks from below:
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Slipper’s as good as new again:
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That should last a whole lot longer than glue! :)

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Karang guni kludges and other hacks.

Looking for Eileen's Origami Page? It'll be up here in a bit!

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