The Fleetwood Group, a US-based designer and manufacturer of RF audience response keypads and voting systems, has standardized on Nordic Semiconductor’s nRF24L01+ 2.4 GHz transceivers in its latest Ativa® audience voting system. Fleetwood currently ships around one million RF keypads a year to some of the world's largest companies and organizations.
The Ativa audience voting system centers on the interactive WRS8200 wireless keypad that runs from a rechargeable lithium polymer battery and employs a large, backlit 3.2 inch QVGA color touch screen that can display fully customizable key/button responses for any given interaction or voting opportunity.
In operation, an Ativa base station equipped with a Nordic nRF24L01+ 2.4 GHz transceiver housed in an enclosure roughly the size of a regular USB memory stick, plugs into a PC USB port from where it can form a secure, two-way RF link with sister nRF24L01+ transceivers embedded into each of up to 15,500 uniquely identifiable WRS8200 wireless keypads over a range of up to 500 ft (about 150 m).
"One of the most challenging aspects of getting such a large-scale response system to work reliably is that everything hinges on the speed and responsiveness [latency] of the wireless link," explained Pat Moody, VP of Sales and Marketing for the electronics division of Fleetwood Group responsible for manufacturing the Ativa product in the US. "This link has to maintain its integrity even in hostile, RF-dense operating environments where the system will have to cohabit with other active 2.4 GHz sources of potential interference within a venue, such as Wi-Fi and Bluetooth."
To achieve this, Fleetwood employs an advanced and patented synchronized polling method and pseudo-random frequency hopping RF protocol that includes integrated Wi-Fi avoidance features. This allows the USB base station to sweep around a venue, time synchronize and individually poll every single keypad of the thousands present within a matter of seconds. If the base station fails to get through to any one keypad, it will instantly retry on another frequency.
Geir Langeland, Nordic Semiconductor’s Director of Sales and Marketing, commented, "Audience response is becoming a regular feature of many public gatherings and events because it heightens participation, interest and retention levels. In addition, as the popularity of audience response systems has grown, so has their level of sophistication and diversity in response to end user requests and feedback. This latest Ativa product platform demonstrates why two-way, ultra low power 2.4 GHz RF technology is a key enabler to making this happen for large numbers of battery powered keypads, and we are proud to have been able to support such a leader and pioneer in the field as Fleetwood Group."
