Wireless miniature PC mouse

21 September 2010

Swiftpoint mouse operates on a portable computer’s palmrest
Swiftpoint mouse operates on a portable computer’s palmrest

The Switfpoint mouse from Swiftpoint transforms a portable computer’s palmrest into a large mousepad.

This provides users with the functionality of a mouse plus the convenience of a trackpad. The mouse employs Nordic nRF24LE1 and nRF24LU1+ 2.4GHz ULP transceivers, and Gazell RF protocol software for precise, low latency wireless connectivity.

Developed by New Zealand designer and manufacturer Swiftpoint Limited, this mouse is designed for on-the-go portable computer users who lack a suitable surface for a desktop mouse (such as whilst travelling on public transport) and find the computer’s built-in trackpads uncomfortable and frustrating to use.

The Swiftpoint wireless mouse is compact and portable, yet provides all the accuracy and functionality users demand from a mouse. The Swiftpoint mouse boasts a pen-like grip which, unlike other micro-sized mice, is comfortable and intuitive to use.

The wireless link in the Swiftpoint mouse is powered by Nordic hardware and software. Each mouse employs a Nordic nRF24LE1 transceiver communicating with an nRF24LU1+ transceiver embedded in a miniature dongle that plugs into the USB port of the portable computer under control. Nordic’s Gazell RF protocol stack, optimised for low latency and ULP operation, seamlessly controls the wireless communication between mouse and dongle.

The ULP characteristics of the nRF24LE1 and Gazell software significantly extend the battery lifetime of the mouse’s small battery (which can be recharged from the portable computer’s USB port). The nRF24LE1 is suited to the mouse’s small form factor because the application microcontroller is integrated with the radio core into a single chip measuring just 4mm x 4mm. In addition, the Gazell software’s Dynamic Proximity Pairing eliminates the requirement for a pairing button on the mouse.

The nRF24LE1 offers a maximum raw data rate of 2Mbps, which enables the rapid communication required for fast, smooth cursor movement and mouse operation. The Gazell protocol includes a high degree of interference immunity from other 2.4GHz radio sources, such as Bluetooth and Wi-Fi, for seamless operation.

“Using a portable computer’s built-in trackpad for extended periods is tiring, slow, and can potentially lead to serious ailments such as repetitive strain injury,” says Grant Odgers, Swiftpoint’s CEO. “While wireless travel mice help when there is a suitable flat surface, there are many occasions when such a surface is unavailable. Our Swiftpoint mouse solves the problem. The key technological breakthrough was being able to produce a wireless mouse that was small and light enough to be operate on the palmrest beside the computer trackpad, yet still operate for many weeks on a single charge. This breakthrough was made using Nordic Semiconductor’s integrated single chip 2.4GHz transceivers, Gazell software, and nRFready reference design. Nordic’s technology has made our intellectual property commercially viable for the first time.”

Ståle Ytterdal, Director of Sales and Marketing in Asia for Nordic Semiconductor, adds: “The nRF24LE1/nRF24LU1+/Gazell combination has been proven in many wireless desktop peripherals, but the Swiftpoint mouse is a unique application because it incorporates the convenience of wireless in a compact form factor that allows full mouse functionality using just the computer’s palmrest as a work area. Swiftpoint have taken full advantage of the incredibly compact nRF24LE1 System-on-Chip, which incorporates an nRF24L01+ transceiver, 8bit microcontroller, and flash or OTP memory on a single chip, and Gazell protocol stack, to shorten development time, and meet the exacting performance and cost demands of the company’s mouse.”

The nRF24LE1 is a ULP system-on-chip 2.4GHz transceiver that enables single-chip implementation of wireless applications. The nRF24LE1’s radio is a fully featured nRF24L01+ 2.4GHz transceiver core including Nordic’s proven Enhanced ShockBurst hardware link layer. It delivers true ULP operation (peak transmit current of 11.3mA (at 0dB output power), peak receive current of 13.5mA (at 2Mbps), a 900nA power down mode, and microampere average current operation) and can run on coin cell batteries. It integrates an enhanced 8051 mixed signal MCU core featuring fewer clock cycles per instruction than legacy 8051 devices. Most instructions need just one or two clock cycles leading to an average performance improvement of 8X using the MIPS (Million Instructions Per Second) benchmark. This high performance combined with 16kbytes of on-chip flash and 1kbytes of SRAM ensures the processing platform is powerful enough to run both the RF protocol stack and application layer with ease.

A wide range of peripherals and power saving modes support the RF protocol stack. A ULP 32kHz crystal oscillator provides high accuracy timing for low report rate synchronous protocols and a 16MHz RC oscillator provides fast start-up times from idle. The 32kHz oscillator can provide timing accurate enough for higher report rate protocols without requiring an external crystal. A security co-processor enables AES encrypted wireless communication. The nRF24LE1 provides a range of nanoamp and microamp idle modes specifically designed for ULP RF protocol stacks.

For the application layer, the nRF24LE1 offers a rich set of interfaces and peripherals including an SPI, 2-wire, UART, 12-bit ADC, PWM and an analogue comparator. As such, the nRF24LE1 is suitable for applications including mice, keyboards, remote controls, game controllers, sports/healthcare sensors, toys and active RFID tags.

With an on-chip voltage regulator (covering a 4.0V to 5.25V supply range) that enables the chip to be powered directly from the USB bus, the nRF24LU1+ does not require an external voltage regulator, saving cost and board space. With a fully integrated RF synthesizer and PLL for the USB no external loop filters, resonators or VCO varactor diodes are required, only a low cost ±60ppm 16MHz crystal, matching circuitry and the antenna.

The nRF24LU1 features six general-purpose digital input/output pins, hardware SPI slave and master (UART) and three 16bit timers/counters. It supports firmware upgrade over USB and a FS2 hardware debugger. In addition, the nRF24LU1+ is air compatible with the nRF24LE1, nRF24LU1, nRF24L01+, nRF24L01, nRF2401A, 02, E1 and E2.

The 128bit AES encryption/decryption co-processor provides industry standard data encryption and decryption at the application level, and the on-chip flash memory features fully configurable write and read back protection, offering complete protection from reverse engineering.

With air data rate of 2Mbps combined with full speed USB, supporting up to 12Mbps, the nRF24LU1+ meets performance requirements of a wide range of applications including PC peripherals, advanced media centre remote controls, intelligent sports accessories and toys.

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