Design News for Mechanical and Design Engineers

Entering lots of data into PDAs and embedded devices poses a problem for those whose fingers are too large for miniaturized keyboards. A Texas startup is hoping that users will find full-sized keys packaged into a small keyboard that can be operated with one hand to be a viable alternative.

The FrogPad has 20 keys laid out in a compact grid, ergonomically designed to let users enter data quickly with one hand. With five function keys and 15 character keys, users can enter large amounts of data more easily than with handwriting systems or those with miniature keys, its developers say. 'You can't edit a spreadsheet using a thumb keypad or a QWERTY keyboard that has very tiny keys,' says Linda Marroquin, CEO of FrogPad Inc. of Houston.

The founders of FrogPad feel the keyboard has a shot at becoming a de facto standard for portables and embedded systems. That can happen if users decide that the importance of entering all types of data prompts them to spend about the same amount of time most people needed to learn the Graffiti handwriting language.

Operators can typically hit 30-40 words per minute after 8-10 hours of training, she adds. The keypad mimics all the functions of a standard computer keyboard, using simple combinations so the character keys can be used for more than one character.

'With 20 keys, we include the function keys. You can do everything you can do with a 101-key keyboard,' says Kenzo Tsubai, who invented the FrogPad concept. Those keys are the same 19-mm size that's been used since the first typewriters came out in the late 1800s. Though miniaturized keys have seen much use in recent years, Tsubai notes that 'studies show that if you shave one-sixteenth inch off the key, it will throw users off. That's why we don't mess with the size of the keys.'

Kenyo Tsubai is hoping is miniature keyboard with full-size keys will become the standard design for portables.

Interplanetary Design Team

The nouveau layout of the FrogPad is matched by the startup's modern approach to its design. The company has a minimalist staff, not yet 10 employees operating on the promise of future income, relying on outsourced product design and manufacturing. Among the design contractors: a government- funded design team whose main focus is outer space.

Outsourcing saves time and money by eliminating the time spent hiring and training personnel. But perhaps its most important benefit is to help the startup compete with well-established keyboard suppliers. Outsourcing serves as a university, 'teaching small companies how to go toe to toe with big companies,' Marroquin says.

The company's first contractor was IDEO, which did the basic physical design. Marroquin notes that getting the contract design firm based in Palo Alto, CA to do much of the mechanical design was a coup, since IDEO is well known for mechanical design. 'I could have gotten the work done for less money elsewhere, but their name really added some prestige,' she explains.

Even though the company's chief engineer, George Batten, is considered an employee, he's actually a contract designer for Advanced Image Measurement Systems of Houston. Batten did most of the basic hardware and software development and remains active in the push to commercialize the keypad.

The self-supporting company recently got another well-known name to provide work for free: the Space Alliance Technology Outreach Program, a NASA-funded agency that helps small businesses develop technology that could be used by the space agency.

SATOP, organized in four states and using engineers from NASA, provides small companies with up to 40 hours of engineering and scientific support for free. There's some interest in a version that could be placed on a space suit, giving space walkers the ability to communicate with on-board computers.

But much of the work focuses on making a model that can be used in Mission Control, giving operators the chance to leave their desks without losing contact with the computers during critical periods of space missions. 'We're working with FrogPad to develop a wearable version so someone can walk around with a wireless product,' says Richard Smith, project engineer at SATOP's Bay Area Houston Economic Partnership.

Smith got 'very excited' about the FrogPad, feeling that it would let NASA's Mission Control engineers enter data as quickly as at a standard keyboard, yet give them the freedom to roam a bit. 'The goal is to let them see everything they'd see at their desk and respond to it using the keyboard,' Smith says.

The latest outsourced development for FrogPad is one that the management team thinks will crack the market wide open. Gennum Corp. of Burlington, Ontario, Canada, developed a Bluetooth module that will eliminate the USB cable now used to link the 5-x 3.5-inch keyboard to its host. 'The minute it's Bluetooth compatible, it's an interface for almost every PDA that's come out since the middle of 2003,' Marroquin says.

Adding Bluetooth required a fairly substantial redesign. 'We're not just adding Bluetooth, we're engineering a complete Bluetooth system,' says Kamal Ali, senior product manager at Gennum.

Gennum is revising the FrogPad's motherboard to accommodate its Bluetooth module and other circuitry needed for battery control and wireless communications. The main aspect of this project is to make room for the Gennum module, which houses a CSR chip, 16 MHz crystal reference, and 8 Mbits of flash on a ceramic substrate. FrogPad's original circuit board was lightly populated, so it wasn't difficult to find room for the 12-x 12-mm module.

The design is straightforward, using the module and implementing the human interface devices profile developed by the Bluetooth Special Interest Group, Ali says. Adding the antenna and rechargeable battery are also common design aspects for Bluetooth products, he adds. Power management will be included in firmware, with a focus on putting FrogPad into its standby mode, a common state for data entry devices. The microcontroller running at full speed with the low-speed USB active requires about 5 mA at 5V (about 25 mW). When the system is suspended, it draws about 300 µA from the USB power bus. That's an aspect of the design that's been considered since the early days, when Motorola's MC68HC908JB8 processor was selected. 'It's fairly powerful, but barely powerful enough for this application,' says Batten. The version FrogPad is using has 8 Kbytes of EEPROM and 256 bytes of RAM, all fully utilized.

Motorola designed the IC to maximize battery life for this type of application. 'We've reduced the leakage current to 20 nA in the power-down mode at 1.8V. That's lower than the degradation of a battery sitting on the shelf,' says Kevin Kilbane, strategic marketing and systems manager at Motorola Semiconductor Products' 8/16-Bit Products Division.

Removing Wires: A wireless links form Gennum connects to PDAs and other Bluetooth-compatible hardware.

Complex Software

The hardware design was fairly straightforward, while the algorithm and software development was very time consuming. Users press the space or number keys to get a second or third character on each key, and the tasks of monitoring which combinations are pressed must be processed quickly, a job handled mainly in firmware and software.

FrogPad has a small operating system, about 8 Kbytes, called the KBEngine. That includes a fairly elaborate table describing the keyboard, with characters corresponding to keys described in part of the table. 'We have a set of layers above the keys, one layer with capital letters, another layer with lower case, one with numbers, and one with symbols,' Batten says.

These layers are selected by states of the system, whether typists have pressed certain modifier keys, for example. When keys are pressed, interpreted code held in the tables runs through sequences, at each step using code to determine the next state. 'This is a state machine with a proprietary programming language,' Batten says.

The software is written primarily in C, though the tables are not described in C. Instead, they are handled as a tabular form for data. That saves space, keeping the tables down to just 1 Kbyte.

As the product moves to specialized markets, Batten is developing 'a friendly way to describe the tables' so OEMs can modify the keys for specific functions of their applications. A program written in C will have interactive graphical arrangements for the tasks used in describing a keyboard, such as determining the keys that are pressed.

Though the technology is new, there's been a big shift in keyboards from the time the first prototypes were built in 2001. The early models used a PS/2 interface, but the shift to USB connections brought subtle shifts that posed a challenge for the unique keyboard. PS/2 keyboards have a built-in repeat function when a key is held down, while USB keyboards offload the repeat determination to the CPU.

That determination is made by measuring the length of time from when the signal that the key has been depressed is sent, then determining how long until it's released. 'We had to put intelligence at the key, recognizing when the key is being held down for a period,' Batten says. That means determining between a short press and release and one that's held for a longer period.

While the designers look at nifty technology, the main thing customers see is size, both in the large keys and small form factor. Applications in the portable world will be a key part of the market, but Marroquin foresees a number of other applications. For example, in telephone call centers, typing with one hand gives captive employees more chance to change their posture.

All of these applications represent potentially large markets. 'The predictions say 1.7 billion Internet-compatible embedded devices will ship by 2006, including things like a fridge that tells you it's out of milk,' Marroquin says.