Build Your Own LED Watch

There was a time in the early 1970s when an LED watch would set you back about $2000. These days, they're considered geeky anachronisms. And what could be geekier than building your own?

Spikenzie Labs recently sent us one of their Solder : Time LED watch kits [$29.95]. It comes as an easy-to-assemble circuit board kit with a case made from four sheets of laser-cut acrylic. You'll need basic soldering skills to assemble the kit. If you're comfortable soldering a couple of ICs, you won't have any trouble putting everything together in about 20 minutes. A fully assembled version is available for $39.95 if you're not the DIY type.

All of the resistors and capacitors are identical values, so it's hard to go wrong. Just make sure you install the ICs correctly -- they're mounted with the markings upside-down. The only tricky part of the board assembly is attaching the battery holder. It's a surface-mount part, which means you'll have to come up with a clever way to hold it in place while soldering it (Spikenzie recommends tape, which is what I used).

Once the board is built, you'll have to assemble a multi-layer acrylic sandwich to form the case. There's nothing particularly difficult here. It's just a matter of making sure that each layer is aligned properly and the control switch doesn't bind. When everything is where it should be, hand-tighten the screws into the pre-tapped holes and attach the "one size fits all" velcro strap.

Tap the button on the right to display the time. It shuts off after a few seconds to conserve the CR2032 battery, and the company estimates it'll last up to five years with moderate use. There's a jumper on the bottom of the board to set the Solder : Time into "always on" mode for use as a desk clock, although you'll need an external power source.

Programming the watch is utterly simple, too. Tap the control button twice and hold it down to advance the time. My only gripe is that the watch only displays 12 hour time. It would be nice to have a jumper that forces it into 24 hour mode, just in case the wearer is unsure whether it's morning or evening. But that's a minor complaint.

Spikenzie Labs has a hit on their hands with this quirky timepiece. It's affordable, fun to build and a guaranteed conversation starter. My rating? Five out of five retrorockets.

Visit the official Solder : Time page for full details and a peek at the online assembly guide.