While most micro-projector makers these days are trying to fit as many ports for different connectivity sources as possible into their products' tiny frames, Acer took the opposite tack with its C120 Projector ($299.99 list). This pico projector connects via USB—and USB alone—to a computer, emulating whatever's on your computer screen. In that respect it resembles some budget projectors we've seen such as the 15-lumen Ray Lite ($159 direct, 3 stars), but the Acer is considerably brighter and easier to set up (though not necessarily to run).

The C120  is an LED-based DLP projector with a native WVGA resolution (854 by 480). Its rated brightness is 100 lumens, which puts it among the pocket projector elite. The only other 100-lumen pico projector we've reviewed is the Optoma Pico PK320 Pocket Projector ($450 street, 3 stars).

The C120 is a handsome little projector, black (glossy on top) and rectangular with rounded corners. It fits in my pants pocket, but just barely. I weighed it on our postage scale at 6 ounces; adding the power adapter brought the total weight up to just 13 ounces. The focus wheel is on the side, next to the lens, which I find preferable to it being in front of the lens, at least for avoiding obstructing the light path with a stray finger. The wheel, though, is very small, and I found it hard to bring the image to a precise focus.

The Optoma PK320 provides a much broader range of connectivity choices, including HDMI, VGA, and composite video. It can also run presentations from internal memory, a micro-SD card, or a USB thumb drive.

Installation and Operation
The projector can be powered either through an AC adapter or over a computer's USB connection. It comes with a USB cable that plugs into the projector with a USB 3.0 connector. It's a Y cable with 2 USB B-type plugs for the computer, so you can run power and data over the cable. You do take a hit in brightness when you power the projector over the USB cable.

When you plug the C120 into a computer's USB port, the projector installs a driver on your system. You have to agree to the installation by clicking the appropriate button in a pop-up window, each time you use the projector. I used the projector with 3 laptops, and was able to run it on all three. However, for one of them I could only get it running some of the time, and wasn't able to determine why it didn't consistently work. Also, regardless of which laptop I used, the USB connection seemed finicky and the connection was occasionally lost. Unplugging and the re-plugging the cables in resolved this for the most part.

When I'd install the driver, it would resize the laptop's screen to 800 by 600 pixels, closer to the projector's native resolution. One can then resize the screen through the Windows Control Panel; the projector supports resolutions of up to 1,280 by 800 and did okay at that resolution, though the image looked better at the lower resolution.

Testing
The projector threw an image about 6 feet diagonal to fill our test screen from about 8 feet away. Although it looked okay in the dark, it was somewhat degraded with modest ambient light, so I did most of the testing with the image size about 4 feet diagonal.

I found the C120's image quality fine for internal business presentations (such as to small workgroups). You could use it for road presentations in a pinch, if you can verify that it will connect smoothly to your laptop via USB—for this projector, USB is the only game in town. Colors seemed reasonably true; there were hints of the rainbow effect common to DLP projectors in which bright areas against dark backgrounds may break up into little blue-green rainbows. Focus seemed slightly soft, and text wasn't very sharp. Video quality was okay for running short clips as part of a presentation.

A USB-only pico projector—and the C120 is unusually bright as such—offers the advantage of low price and—at least in theory—simple setup and operation. Downsides are that it's not as versatile as a full-featured model such as the Optoma PK320, and it's a one-trick pony—if you have problems connecting via USB, you don't have any other options. (If the C120's driver doesn't load, rebooting the laptop will sometimes resolve it—though you wouldn't want to have to do that when you're time pressed and presenting to a small group while on the road.) You don't want to misplace the USB Y-cable, as cables with USB 3.0 plugs aren't as easy to find as the earlier cables.

If USB connectivity is all you're looking for in a pico projector, the Acer C120 may well be your model of choice. It's considerably brighter than the Ray Lite and other USB-only projectors we've looked at, and less expensive than fuller featured models.

COMPARISON TABLE
Compare the Acer C120 Projector with several other projectors side by side.

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