While many high-end modern cars are now coming with a sophisticated Head-Up-Display (HUD) built in, owners of older (or cheaper) models are stuck with a dedicated navigation device or cradled smartphone blurting out directions and pointing the way. If you're feeling adventurous, you may be able to shoe-horn a retrofit kit into your old jalopy, or you could take the plunge and stump up for a new car, but navigation veteran Garmin has another option. Its new pocket-sized, portable HUD wirelessly connects to a smartphone running a navigation app, and throws directions and useful information onto the inside of the windshield.

The company's first portable Head-up Display for smartphone navigation apps, the imaginatively-named HUD can receive its source information from any Bluetooth-enabled iOS, Android or Windows Phone 8 smartphone running a Navigon or Street Pilot app.

Drivers are promised at-a-glance, easy to follow directions in the line of sight, including turn arrows, lane indicators, distance information, and estimated time of arrival. It can also display the vehicle's current speed, together with the speed limit for the road you're driving down, will alert you to potential delays ahead, and let you know when you're about to hit a safety camera zone.

Users can choose whether to display HUD's information on the included transparent film that sticks to the inside of a windshield, or via the supplied reflector lens that's attached to the device itself. The 7,700 cd/m2 vacuum fluorescent display technology benefits from automatic brightness adjustment for consistently crisp green or red projected information, whether driving in bright sunlight or the dead of night.

Turn-by-turn spoken instructions can be pumped out through a smartphone speaker or through a Bluetooth car stereo, and any music that's being played through the mobile device or car speakers will be faded out before a voice prompt sounds.

The 4.25 x 3.46 x 0.73 inch (10.8 x 8.8 x 1.9 cm), 9.77 oz (277 g) device comes supplied with a power adapter that includes a USB port to top up the smartphone's battery while driving.

The Garmin HUD will be available shortly for US$129.99, but you can add at least another 30 bucks onto that price tag for the necessary smartphone app.

Product page: Garmin HUD