When it comes Smart LED light bulbs, which can be dimmed and made to change colour, the most popular product must be Philips Hue, using the Zigbee protocol, which you can control via iOS and Android devices though a Zigbee gateway, and costs about £50 on Amazon. Alternatives have started to show up such as LIFX, with WIFI technology, that you can control with recent iOS and Android device without the need for a gateway, but with a price starting at £80.