Wireless PC Peripherals Point the Way for RF Remote Control
Thu, 07/08/2010 - 1:02pm
Even though we are only in the early stages of a digital content revolution, consumers can already access a vast array of digital content, including dozens of cable channels, video stored on the hard disks of set top boxes, music and photo libraries stored on PCs, or movies cached on remote servers. And in the next several years the migration of content distribution from traditional broadcast networks to the kind of Internet TV services mentioned above via Local Area Networks (LANs) or Digital Living Network Alliance (DLNA) connections will rapidly accelerate.
While for simple, low cost control applications IR isn’t going to disappear, its basic “one-button-one-operation” and step-by-step navigation can’t cope with the consumers’ desire to quickly and easily navigate web browsers, Electronic Program Guides (EPG), and library menus. What’s needed is a remote control with an advanced, intuitive interface such as a touchscreen, touchpad, or scroll wheel.
Such advanced navigation demands the fast response, bi-directional communication, non-line of sight control, and extended range promised by RF technology. However, engineers tasked with specifying an RF technology (operating in the unlicensed 2.4 GHz ISM band) for remote control are presented with several viable alternatives. They can chose from proprietary options (such as the nRF24LE1 and Gazell protocol from my company, Nordic Semiconductor), IEEE802.15.4 radios running the RF4CE consortium’s (now part of the ZigBee Alliance) protocol, IEEE802.15.4 radios running proprietary protocols, and, (later this year) Bluetooth low energy chips with a customized RF protocol.
From Desktop to Living RoomRF technology utilized for remote control with advanced navigation requires low latency (for rapid response to user input), good data integrity (to minimize the need to resend corrupted packets), and low power consumption (because next-generation remotes are likely to be used more intensively than traditional IR remotes but will require a similar battery life to meet mass-market consumer expectations).
This is quite a challenge. The good news, however, is that engineers designing RF remote controls can turn to the wireless PC peripherals sector (mice, keyboards, and joysticks) for inspiration because their peers have solved exactly the same problems.
The RF technology powering a wireless mouse, for example, is ideally suited to the challenge of RF remote control and will easily transfer to a new form factor. This is a proven technology used on millions of “wireless desktops”, employing inexpensive, robust, interference immune 2.4 GHz transceivers and customized protocols. A wireless mouse provides an advanced navigation interface (seamless movement of a cursor on the PC’s monitor), latency of just a few milliseconds, and power consumption of just a few milliamps during extended operation (yielding battery life from two AAA cells of many months).
While it’s actually feasible to use a wireless keyboard and mouse to navigate an EPG displayed on a widescreen TV, it’s hardly the most aesthetic or ergonomic solution. Peripherals from the office desktop don’t migrate unobtrusively to the domestic living room. What consumers are demanding is advanced navigation functionality merged into a sleek remote control unit with an easy-to-use, intuitive interface and familiar form factor.
Adapted for SurvivalThere is one other key characteristic that makes PC peripheral wireless technology a good choice for powering RF remote controls: it is highly immune to interference to transmissions from other 2.4 GHz sources. RF protocols used for wireless desktop peripherals have adapted to survive in a hostile radio environment saturated by signals constantly emitted by Wi-Fi modems and routers, Bluetooth-equipped cell phones, PDAs, PCs, and cordless phones.
While, in comparison, today’s living room is a relatively benign radio environment, tomorrow will be different. 2.4 GHz Wi-Fi will pervade that space, as it becomes a standard fitment in set top boxes (STBs) and DVD players to provide wireless connectivity to the TV. Engineers looking to future-proof their RF remote designs are well advised to consider one of the toughened RF protocols powering contemporary wireless peripherals for their product.
Of the technologies vying for a share of the RF remote control market, Nordic Semiconductor’s nRF24L01+ and nRF24LE1 proprietary technology enjoys the largest penetration into the wireless PC peripherals sector with the company shipping millions of chips per month into this market. (This is not something that can be said about IEEE802.15.4-based technology.)
Bluetooth low energy will become a viable alternative for remote control, but the chips are not ready for commercial release. So it will be a while yet before engineers can start designing RF remote controls with this low power version of Bluetooth. (Nordic has played a key role in developing the specification for Bluetooth low energy and will be one of the first companies to deliver chips once the Bluetooth SIG adopts the full specification.)
In contrast, Nordic’s proven nRF24LE1 System-on-Chip (SoC) - integrating 2.4 GHz transceiver, 8-bit microcontroller, and flash (or less expensive OTP memory), and running the company’s Gazell RF protocol software – is an ideal RF remote control solution available today.
After gaining an EE degree at the University of Strathclyde (UK), Svenn-Tore Larsen began his career at Philips Semiconductors working on the 68000 microprocessor. In 2001, the board of directors at Nordic VLSI – as Nordic Semiconductor was then called – asked Larsen to join them. In February 2002, Larsen became CEO of Nordic Semiconductor.
REFERENCES1. “Connected TV Users Demand Improved Web Interface and Control Devices,” Strategy Analytics press release, February 5, 2009 (tinyurl.com/y4tgxk9).