Visible light communications technology could be in toy shops as early as next Christmas!
My previous top 10 VLC applications post has been well cited but did not include toys as an application. If it had been my top 11, then toys might have been there and on reflection it probably warrants a top 10 position as I can see the application being one of the first to hit the shops. With just one month to go until Christmas 2011, I know we won’t be seeing anything this Christmas but what about Christmas 2012?
Before answering the question, let us consider why VLC should be used in toys?
Toys continue to grow in sophistication and many now have radio control and a multitude of LED flashing lights. If we therefore consider that the LED lights can be used to transmit data over a short range as an alternative to radio, then all that is required is a photo-detector. However, there is a clever trick that can be played to avoid increasing the bill of materials. It is actually possible to re-use an LED as a photodetector device. Here is the technical bit: when a voltage is applied across an LED in the “correct” direction (called forward biased) it will emit light, when the voltage is applied in the opposite “wrong” direction across an LED (called reverse biased) then the current that will flow through that LED becomes proportional to the light that falls on it. In other words, a reverse biased LED becomes a photodetector. With a simple circuit it is easy to switch between these two modes. More detailed technical information can be found in an excellent MERL whitepaper from 2003.
So the answer to the why question is that all of the components required for short range communications using VLC between toys already exits. This can save the cost of adding radio circuits into toys and would allow lower cost electronic toys to have communications capability, and it is safe too. It just requires a little engineering ingenuity to unlock this functionality.
So my prediction – VLC in toys by Christmas 2012!