Introduction: Google Glass Locutus Laser

About: I'm a prototype developer, and I make VERY SERIOUS videos about making stuff! Every Monday, I show you a new project, teach you some fun facts, or pull back the curtain of product development.

Some say Google Glass turns its users into the Borg. Why not look the part?

Blow minds with this straightforward hardware hack that adds a frickin' laser to your cutting-edge heads-up display.

You can control it with a voice-enabled sideloaded APK, and even integrate it into your own apps. It's powered by Glass itself, so you don't need external batteries and stuff.

A word of warning: This project involves some very tricky soldering that's nearly impossible without quality tools. You'll also need a Google Glass and the skills to sideload an app.

This project is complete - I'm not developing a new version, not providing support for other users' builds, and ignoring all feature requests.

Step 1: Equip Yourself

Materials:
- 1x Adafruit Google Glass Flashlight
- 1x laser pointer module. Low-powered is better.
- 2x jumpers with at least one female end (or one jumper with two female ends, jeez)
- 1x Glass Camera Cover or zip tie (or balls of steel)
- Lead-free solder
- Hot glue sticks

Tools:
- High-quality temperature-controlled soldering iron with fine SMT tip
- No-wash flux
- Hot glue gun
- Quality flush cutters
- Electronics tweezers
- Self-closing tweezers or helping hands
- Quality wire strippers

Don't skimp on the tools! This project involves abusing some SMT pads. It's really easy to permanently ruin the materials with crude tools.

Step 2: Prepare the Parts

I'm using an early version of Deqing's Glass Flashlight that has a through-hole LED. The newer version uses a SMT LED. The instructions are nearly identical between the versions.

Basically, we're cutting off the LED and replacing it with the laser. There are couple more hacks, but that's it in a nutshell.

If you're hacking the through-hole LED version, cut off the LED as close to the light as possible, leaving as long leads as you can.

If you're hacking the SMT LED version, use the flush cutters to break the LED in half at the center. Wipe the pieces off the pads with your soldering iron. There's a resistor near the LED - don't worry if you accidentally remove it too.

Cut the jumpers to leave about 3" of wire connected to the female ends. Strip the wires, twist them tight, tin with lead-free solder, and cut them down to about 1/16".

We're using lead-free solder because Deqing's boards are ROHS-compliant, and mixing eutectic with lead-free solder weakens the joint.

Step 3: Solder the Wires

Stabilize the flashlight with locking tweezers or helping hands.

Apply flux to the wire ends (through-hole LED) or LED pads (SMT version).

Solder the wires into place. The negative wire is connected directly to the microcontroller.

While soldering the positive wire, short the nearby series resistor with a blob of solder. Your laser should already have a 100 Ohm series resistor, which is fine.

Double-check for shorts, and LIGHTLY tug the wires to check for weak joints.

Step 4: Test

Before proceeding, let's test the unit.

Connect the jumpers to the laser module, sideload Deqing's Glass Flashlight app, and plug the dongle into your Glass' USB port.

Don Glass and say, "ok glass, toggle flashlight". The laser should turn on. If not, try swapping the positive and negative wires. Getting the polarity wrong can't damage your Glass or flashlight module, so don't worry.

Step 5: Put It Together

Snap the enclosure onto the PCB. Squirt a little hot glue into the hole and smooth it with a wet finger. This prevents accidental tugs from snapping the wires off the board.

Attach your camera cover or zip tie to Glass' hinged bit and secure the laser to the underside with a dab of cold-melt hot glue. Don't worry about overflow - the glue is easy to snap off Glass' polycarbonate enclosure.

If you don't have a camera cover, 3D printer, or zip tie, you can glue the laser directly to Glass. Do not use hot-melt glue. The glue will become brittle and snap off if you throw Glass in a freezer.

Finally, plug the dongle back in and reconnect the wires. Your Google Glass Locutus Laser is complete!

Step 6: Resistance Is Futile

Now that you're all wired up, why not make some dreams come true? Go out there and be the Terminator you wish to see in the world.

For a straightforward next step, why not fork Deqing's source and change the voice trigger to something more appropriate? "ok glass, fire the frickin' laser" seems like it'll get the job done.

Although the laser is only running at partial power, be careful not to nail people in the eye! I bent mine to chest height just to make sure.

Thanks to Deqing for building the flashlight WAY before USB host was enabled in Glass, and props to Adafruit for producing and selling such a niche item.

I'll see you guys in the future!

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