UPDATE: Blinkybug Kits, which include all the parts to make 4 bugs, are now available on Make Magazine's online Maker Store.

Blinkybugs are small, eletro-mechanical insects that respond to stimulus such as movement, vibration, and air currents by blinking their LED eyes. They're incredibly simple, yet have a certain lifelike quality.

I've been making variations of these for a while now, and showing others how to make them at museums, fairs, workshops, etc. It isn't rocket science, but there's some tricky soldering involved, and they usually take a person at least an hour to put together for the first time.

I wanted to come up with a solder-free version for the workshop I was organizing for the http://www.makerfaire.com/ 2007 Maker Faire], which took place May 19 + 20 in San Mateo, CA. So after a bit of experimenting, I came up with this simpler design.

Step 1: Tools and Parts

Tools you will need:

Glue gun + glue sticks
Rotary tool w/ metal cutting blade (a hacksaw or similar may work)
Safety goggles
Metal file
Measuring tape or yardstick
Wire cutters
Needle-nose pliers (2 pairs would be nice)
Permanent marker
Scotch tape
Scissors

Parts:

.009" guitar string
Coin-cell battery
5mm LEDs (2 per bug)
Pipe clieaners (aka "chenille sticks")... assorted colors.
Coin cell battery... 3V 2032 type.
Thin copper tubing: 1/16 x .014

I obtained the copper tubing at a hardware store, and it should also be available in hobby shops. The 1/16 is the outer diameter in inches, and the .014 is the wall thickness. Its inner diameter happens to be about .035", which is important because the guitar string needs to fit through (which is .009").

LEDs can be found anywhere on the webernet, and are actually fairly cheap at Radio Shack if (and only if) you buy the variety pack. One can obtain the coin-cell batteries at your local drug store, and they are also available widely online, such as at DigiKey. You should be able to get "singles" of the guitar strings at any music shop. The pipe cleaners can be found at tobacco shops and arts + crafts suppliers.

Step 2: Preparing the Guitar String

The guitar strings I use (D'Adarrio) are 39" long, so may be cut into three 13" pieces (One bug requires a single 13" length). First trim the end with the ball and the little extra twisted bit, then measure and cut. Put these aside for now.

Step 3: Prepare the Copper Tubing

The copper tubing is cut into 1 1/2" lengths (1 piece per bug). This will act as the guitar string / antenna "guide," so the guitar wire must fit through the tube after the pieces are cut. This turns out to be tricky as it's very easy to block the tube opening when cutting. I find that my Dremel tool does OK most of the time, but on many pieces I end up bunging the thing up. Wire clippers definitely do NOT work, as they unfailingly crimp the ends closed.

Measure and mark the copper tubing at 1 1/2" inch intervals. Now carefully cut the copper tubing with your rotary tool... of course while wearing eye protection as little copper bits will be flying every which way! Set it at a high speed, and let the tool do the work... don't force the tubing against the cutter.

I tried this with a hacksaw with little luck... maybe you'll do better! For the Faire I'm getting them pre-cut at the factory to bypass this trouble.

Finally, clean up the cut ends with a metal file.

Step 4: Antenna Guide

This piece will serve as a stable base that holds the guitar string "antennae" in their proper position.

Grab a single length of guitar string and a single piece of the cut tubing. Thread the string through the tubing, and pull the tube to the middle-position of the cut guitar string (centered at 6 1/2").

Now, holding things in place so the the tube doesn't slide around, grab the tubing near its center and bend it in half, forming a "V" shape. The angle should be fairly small, around 45 degrees or less. At this point, the guitar string should not be in danger of slipping out of position.

Next, the top 3rd of each arm of the "V" should be bent. If the V is layed flat, the bend should go "upward" about 45 degrees. I don't know how to explain it better than that so hopefully the pics will make it clear! Two pairs of piers come in particularly handy here.

Step 5: Prepare the "eyes," Part One

Grab a couple LEDs of the same color (or not). Take a look and see that one of the wire leads is longer than the other. This is the anode, or the "+" side of the LED, and the shorter is the cathode, or "-". This is important, as LEDs only work in one direction! If you're not sure that the wires have never been cut (maybe they were salvaged from another project), then look closely at the LED from below. There will be a flat portion of the round plastic package. The lead nearest this flat bit is the cathode.

Bend the anode at the base of the LED so that it is 90 degrees from the cathode. Repeat for the other LED.

Next, cross the ends of each cathode, grabbing the ends with pliers. Twist it like a twist-tie, giving it 3 or 4 turns. The LEDs should remain pointing in more or less the same direction, and the anodes should remain roughly parallel. The two LEDs should now be firmly twisted together. If it seems to have a bit of wiggle, give the twisted part a squeeze with the pliers. Mash it good.

Step 6: Prepare the Eyes, Part Deux

Next, create a small loop on the end of each anode. Grab the tip of one anode with the end of the needle-nosed pliers, and give it a turn, rotating it outward until a small loop is formed. Leave a small gap in the loop for now, as the guitar string will need to sneak through.

Repeat the same for the other anode, twisting it in the opposite direction.

Step 7: Assemble Antenna, Eyes, and Body

For this step you will need the eye assembly, the battery, and the antenna assembly. Note that the battery has a "+" side (it's marked).

Grab a piece of scotch tape, about 2" long. Hold the lower part of the "V" of the antenna assembly against the "+" side of the battery. Lay the tape across the lower part of the "V," so that equal lengths of tape are extending in either direction. Press the tape firmly on the "+" side so it holds the "V" in place.

Next, hold the twisted leads of the LED assembly along the "bottom" of the battery (opposite from where the antennae are attached). The LEDs should point in the same direction as the arms of the "V," and the looped anodes should extend "upward" (that is, in the direction of the "+" side of the battery). Tightly wrap the tape around the entire battery, so that everything is held firmly in place.

(Figuring out how to fasten this together without soldering was key in simplifying the process... I definitely took some inspiration from LED Throwies!)

At this point, the LEDs may light up if the guitar string makes contact with the LED anodes. For now, gently bend the anodes out of the way.

Step 8: Give It Legs

The pipe cleaner "legs" are going to be attached to the bottom of the battery (where the LEDs are attached) with hot glue. Plug in your glue gun and let it warm up.

Grab some pipe cleaners and cut them into roughly 3" pieces, and arrange them like in the picture.

Have the assembled bug body on hand, and drop a blob of glue onto the center point of the legs. I'm pretty sloppy in these pics, as hot glue is fairly forgiving. But you might want to be careful to not let too much get onto your work surface.

Quickly stick the bug, bottom-first, onto the glue-blob as shown. Give it a minute or so to cool and pick it up from the work surface. (Hopefully it won't be stuck!)

You might want to apply a little extra glue to the underside of the legs to make sure they're solidly attached.

Give the glue a few minutes to cool down and set.

Now bend the legs into a buglike pose!

Step 9: Line Things Up

Almost done: the next step is to get the antenna (guitar string) to pass through the anode loops. Hopefully, the antenna guide (copper tubes) are pointing the antennae in roughly the correct direction.

The objective is to get the guitar string to pass through the anode loops so that when the bug is perfectly still, the antennae don't touch the sides of the loop. However, with any movement or vibration, the antennae will make contact with the loops, close the circuit, and momentarily light up the LEDs.

Using a pair of pliers (or two), try to get everything aligned as described. It helps to grab the entire "loop" and rake it back a bit, so that the guitar wire is perpenidicular to the loop. If you left a gap in the loop, you should be able to easily pass the guitar wire in. If not, you may have to pull the loop open a bit with the needle-nosed pliers. Gently squeeze the loop closed once it's in.

You will also want to get the eyes in a position that you like. This all requires a certain amount of futzing until things get lined up.

As a final step, you might want to attach little scotch-tape flaps on the end of the wire, whcih makes them more sensitive to wind, and less likely to poke you in the eye.

You should now have a working blinkybug... the eyes should be "off" when the bug is sitting undisturbed, but should blink rhythmically when you pick it up, move it, or it catches a breeze. If the eyes seem stuck on, you will need to adjust the position of the loops. If the bug does not seem sensitive enough, you might want to try to make the loops a bit smaller.

Enjoy your bug!