Blind since birth, the 29-year-old Spanish interpreter says mobility is a constant consideration. In the age of talking calculators, Braille-based global positioning devices and household appliances with sound cards, mobility still comes down to the nuances of perception and the strategic use of a white cane.

Like most blind young adults, Florez is tech-savvy. She uses special computer programs to scan and read snail mail and checks her e-mail online, but when it comes to locating a classroom or a hotel room, she says it's still very difficult.

UC Santa Cruz Professor Roberto Manduchi hopes his inventions will help change this. Along with graduate student Dan Yuan, the engineering professor is developing a laser-based range-sensing device that can relay spatial information back to its user. The electronic instrument beeps various sounds, alerting the user about a curb, step or obstacle nearby. "We are currently trying to make it less geeky and more practical," says Manduchi as he lifts the bulky metallic device with both hands. It looks like something out of a Cold War science fiction movie, yet quickly proves its value.

He points the contraption toward the door and a red laser point appears on the wooden surface. At the same moment, a high-pitched piano note rings through the air. A lower note is played when the beam hits a box on the floor, and as the pointer moves quickly from one object to another it begins to sound like a small child pounding away on a grand piano.

"We will eventually go with a less obnoxious sound system," jokes Manduchi. But his concept appears to work -- if you listen carefully, you can recognize the obstacle ahead. Eventually, unique audio signals will be used to distinguish a curb from a slope and a step. The device can also compute distances and may potentially relay information about length and depth to the user.

According to Manduchi, it works much like an ordinary laser pointer, but includes a digital camera and computer processor. After the laser beam is projected onto a nearby surface, the camera records the position of the beam and the computer determines its distance. "It's an idea common in robotics," says Manduchi.

The electronic cane computes distances by triangulation, meaning the camera sees the angle at which light is returned from the laser beam. By using simple geometric equations, the computer can then determine the distance of the point of light.

While at the Jet Propulsion Laboratory in Pasadena, Manduchi used the same technology to help robots sense the world around them. After completing his doctorate in Italy, he worked at Apple Computer, Stanford and UC Berkeley before settling down at UCSC, where he's been for the past 12 years.

"Right now we are trying to see how a blind person would use the device," says Manduchi. "If it doesn't solve the right problem, it isn't useful."

In comparison to the white cane, it has two major advantages. It doesn't require physical contact with the object it's detecting, and it can identify objects that lie beyond a cane's reach. But like all electronic devices, reliability is a factor.

"Canes rarely break and they don't have batteries," says Manduchi. "How can we compete?" Yet based on experience, Florez predicts the primary issue will be training, not reliability. As guide dogs get sick and canes can break, many blind people stash a folded cane in their purse or backpack just in case.

But using a cane, a guide dog or even an electronic device isn't as easy as it looks. The movement of the cane has to be synchronized with each step so that there is enough time to process information and react, and blind people have to guide their dogs and listen carefully to the world around them for clues.

"Technology will only work if it's used in combination with mobility training," Florez says.

Certified orientation and mobility instructors teach classes on using a cane, and Florez predicts a similar approach will be needed if any new gadget is to be successful. But the invention won't be officially put to use until some bugs are worked out.

The device took two years to develop and still needs lots of tinkering before being released for open trials. It needs to be miniaturized and made more reliable, and Manduchi recently received sponsorship from the National Science Foundation to do that.

Manduchi hopes his invention will eventually fit inside a pocket-size camera phone, and that the end product will be both affordable and convenient. "It's really just an issue of funding," says Manduchi. He hopes to raise enough money to hire blind researchers to work on the project, and hopes his project will attract disabled graduate students to the sciences.

"I was so excited when I started to derive all the equations," says Yuan. Now that the concept has been proved, he is anxious to move forward with the development of a better model.

If this project takes flight, Manduchi has other ideas as well. Along with Alessandro Temil, an Italian graduate student, he is developing a system that uses a compact camera phone to identify small tag-like markers. When the camera phone recognizes one of the tags, it plays a special tune. The idea is that a blind person might place tags on the door to a hotel room or at the local bus stop and then use the audio signals as a guide.

His lab is also working on a "force-feedback mouse" that will allow a blind person to explore a map.

"I want to do something useful," says Manduchi. "All technology has a social implication. I want to do something positive."

Amy Coombs wrote this piece for Good Times in Santa Cruz, where it originally appeared. Contact us at insight@sfchronicle.com.

This article appeared on page E - 2 of the San Francisco Chronicle