The growing attraction of using voice commands in Bluetooth Smart remote controls


The growing attraction of using voice commands in Bluetooth Smart remote controls

Mark de Clercq, Product Marketing Group Manager at Dialog Semiconductor, sees voice as the next big thing in remote controls

Keyboards, touch screens, gesture and motion control are now all commonplace in consumer electronic products. But all of these technologies come at a price, and not just in monetary terms. These human-machine input methods impact design complexity, component count, product size and, critically in battery-powered products, power consumption. And battery life has a huge impact on a product’s consumer appeal.

For remote control unit (RCU) applications, the interest in using voice commands is growing fast. It’s easy to see why. Microphones used in high volume consumer devices, whether electret types or MEMS versions, are simple, low cost devices manufactured by the billion each year. An operating frequency range of 100Hz to 10kHz is more than adequate for voice commands, so more advanced microphones are not needed. This again keeps costs low for the very price-sensitive RCU market.

Two other factors make voice activation effective and attractive. The first is that voice recognition software has made huge advances in recent years, to some extent due to the increased processing power available from semiconductors. That said, voice command applications are nowhere near as demanding as dictation; it’s much less complicated because relatively few words need to be recognised. 

The second factor is that many wearable devices are very small, so not all of them have enough space to accommodate conventional switches, touchscreens or other input methods.

Following the launch last year of Dialog’s tiny, ultra low power Bluetooth Smart solution – the SmartBond™ DA14580 - we looked to extend the product family to make it easier for customers to implement voice commands in remote control units.  SmartBond devices combine a Bluetooth low energy radio with an ARM® Cortex®-M0 application processor and intelligent power management. Product designers can access the ARM® processor via 32 GPIOs to create fully hosted applications.

Dialog’s expertise in consumer audio is well established – hundreds of millions of our audio codecs have shipped in the last few years; they’re used in everything from cordless telephones to gaming devices.

It was therefore a natural product evolution for us to create the SmartBond DA14582 – a version of the DA14580 optimised for voice by integrating an analogue audio codec with native support for microphones. With an analogue MEMS or electret microphone, it’s really plug-and-play and we offer a reference design showing how to connect it. The microphone gain can be adjusted from 0 dB to + 30 dB in 2 dB steps.

We’ve calculated that under typical usage models, voice controls based on the DA14582, whether for set top boxes, smart TVs, games or smart home applications, will operate for two years or more from dual NiMh batteries. Perhaps most important of all, they’ll be easy to develop and manufacture because all the electronic functionality will be delivered in a single SmartBond SoC.

SmartBond SoCs come in QFN packages with a 0.5mm pin pitch. This allows manufacturers to use very low cost PCB material (phenol-type PCB or single layer FR1 PCB) to lower the cost of the total system. This is critical in applications such as remotes where the PCB is fairly large compared to those in many other consumer electronics products.

IHS estimates that 56 million Bluetooth Smart remote controls will be made each year by 2018.  There are compelling reasons to believe that a large and growing proportion of these will feature voice control because it costs less, works better and enables batteries to last much longer.