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Device Profile: Levelstar Icon PDA for visually-impaired users

Jul 25, 2007 — by LinuxDevices Staff — from the LinuxDevices Archive — 7 views

Levelstar Icon PDALevelstar used embedded Linux to create a PDA (personal digital assistant) for visually impaired users. The “Icon” has a custom hardware design with built-in 30GB hard drive, WiFi, Bluetooth, and USB, and comes with a full complement of “life managing software,” much of it written from… scratch for blind users.

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According to founder and lead developer Marc Mulcahy, the Icon is the only PDA for blind users to integrate a hard drive. He expects the Icon's drive to become a “huge advantage” next month, when the National Library Service for the Blind and Physically Handicapped starts offering its enormous library of talking books in downloadable form.

Larger view of Levelstar Icon PDA
Instead of a power-hungry LCD touchscreen, the Levelstar PDA for blind users has stereo speakers and a telephone-style keypad
(Click to enlarge)

Meanwhile, the Icon features close integration with, a service offering 32,000 downloadable books and 150 U.S. newspapers and periodicals. “With the Icon's hard drive, you can very easily read a lot of books,” Mulcahy said. “It's also nice to have a hard-drive based mp3 player,” he added.

Levelstar docking stationBesides reading books aloud and playing music, the Icon can help visually-impaired users browse the web, send email, peruse email attachments, take voice and text notes, and manage personal information such as phone numbers, addresses, and appointments. An available “dock” (pictured at right) adds a full-size keyboard, while an optional dongle adds USB client and host ports.

Additionally, the Icon shares the same embedded hardware and software platform as the American Printing House “Braille Plus,” a design variant with a six-key braille keyboard instead of a telephone-style keypad.

Icon in the front pocket of a young lady's denim jeansMulcahy says the Icon competes favorably on price and features with other computing devices for blind users. He explained, “Our competitors fall into two camps. In the first, they take a standard Pocket PC and add software to make it talk. Screen reading applications typically cost $600, so you're in the $1,000 range for just a standard PDA, and there's a lot of reasons you might not want that. The second would be the customized devices for the blind, like ours. These devices usually cost between $2,000 and $2,500, and are the size of our system with the dock.”

Another advantage for the Icon, given its ARM architecture, is battery life. “I don't think we're at the max of what we could do [to prolong battery life]. Because of the hard drive, the Icon gets eight hours plus if you're just reading and listening to music, but about half that if you're using WiFi,” Mulcahy said.

What's under the hood?

The Icon is based on a custom hardware design outsourced to an unidentified partner. The design is based on an Intel XScale PXA270 processor clocked at 520MHz. It has 64MB of RAM, and a built-in 30GB hard drive. Additionally, there's 256MB of flash storage (200MB available), which can be expanded via a MiniSD card slot.

I/O includes Bluetooth 1.1 wireless, 802.11b WiFi, and (obviously) audio. The Icon offers built-in stereo speakers, eighth-inch (3.5mm) stereo mini-jacks for headphones and microphone, and a tenth-inch (2.5mm) headset jack. The device comes with a mono earbud and a mono mic.

The Icon measures 5 x 3.4 x 1 inches (130 x 85 x 25 mm), and weighs 7.4 ounces (207 grams). It has a user-replaceable lithium-ion battery.

Optional dongle for USB host and clientAdditionally, the Icon is optionally available with a dongle (pictured at right) that adds USB 1.1 host and client interfaces. The client port can be used to connect the Icon to a PC as a mass storage device, or as a USB network device capable of sharing the PC's network connection.

Mulcahy said Levelstar licensed Belcarra's proprietary USBLAN Linux stack, partly because at the time, Linux's USB client did not work well on the PXA270. Belcarra added PXA270 support to USBLAN more than three years ago.

On the software side, the Icon uses a 2.6.18-series Linux kernel, along with the busybox toolkit, python libraries, MiniMo browser, and open source document format conversion tools. The rest, Levelstar wrote in-house. “All the software on top is our own. Most was written in python,” Mulcahy said.

The Icon's software suite includes:

  • Calendar
  • Address book
  • Web browser based on MiniMo
  • Email
  • Word processor capable of importing .doc and .rtf files, and supporting text and braille in the same document
  • Music player (soon to be gstreamer-based, which could in theory enable support for backends such as Rhapsody and UPnP)
  • Pod cast
  • Voice recorder
  • Journal
  • Clock
  • Stopwatch
  • Calculator
  • Book player with support

Mulcahy said Levelstar looked at commercial Linux support, but ultimately passed. “MontaVista's pricing structure is just not oriented toward small companies,” he said. “They'll give you the basic stuff, but you still have to add support for your own hardware, so it isn't clear how much you really gain.”

Mulcahy added, “With TimeSys, it's a question of 'how do you compare to OpenEmbedded?' OpenEmbedded is just amazing. It's a pain to get up and running, but then it's really slick. You can build an entire Linux distribution with it.”

Mulcahy said that over the past three years, between three and five developers have worked on the Icon's Linux-based software environment. Some worked for American Printing House, the company that markets the Icon's braille-oriented cousin, the “Braille Plus.”

Asked about braille's popularity in the era of speech-to-text programs and screen readers, Mulcahy replied, “It depends on who you ask, but roughly 10 percent of blind people know braille. However, the percentage who are technically oriented and know braille is higher, because of braille display technology — devices with pins that move to form braille characters. That's why braille is surviving. We don't have a braille display yet, but we're leveraging braille as a really cool way to input text.”

Mulcahy expands, “The Braille Plus is the same size as the Icon, but has a six-key braille keyboard. Braille is not quite as fast as touch typing. It's in the same vein as the language of a court reporter. There is a bunch of shorthand where one character can mean multiple things. But its relatively quick. I'd expect a student would be able to take notes at about 40-50 words per minute.”

He adds, “The Icon itself has a telephone-style keypad, and a two part design, so you can just take the Icon when you anticipate that you will not be needing to enter a ton of data. You can still 'text in' like a phone, or type voice memos.”

Mulcahy said the Icon reached market last December, and has since found a receptive market. The device can replace a laptop for users primarily interested in browsing the web and managing email. And, users love the hard drive, and easy integration with digital audio book services. “ integration has been really well-received. And the built-in connectivity. And, if you research the competition, it's very competitively priced,” he added.


The Icon is available immediately, priced at $1,400. Available separately is a hardware maintenance agreement, software update subscription (via download or miniSD card), case, replacement battery, USB port dongle, and user manual in braille. GPS support is planned for a future revision.

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