Bluetooth mobile phone-controlled dimming LED lights

　　With, October 30, 2012, Philips sold the latest high-tech LED lights in Hue series AppleStore, and only sold by Apple. Hue series will be completely self-definition, and by one of three primary colors red blue and green LED bulbs can be mixed out of 16 million kinds of colors of light. The whole process is completely on the App iPhone to control. Giving rise to a new thinking intelligent light control development, domestic stakeholders have also studied. Hue is considering using WiFi wireless control, and domestic WiFi is not universal, this study used more generally Bluetooth technology, Bluetooth cell phone communication with the microcontroller to generate an adjustable duty cycle PWM wave signal control LED driver circuit implementation of LED dimming DIY color.

　　Pulse width system (PWM) dimming technology

　　PWM dimming is a use of simple digital pulses repeatedly switch dimming LED driver technology. Application of systems that only need to provide a wide, narrow different digital pulse can be easily realized by changing the output current, thereby to adjust the LED brightness. PWM dimming the advantage of a large dimming range, as long as sufficient bandwidth, any analog value can be encoded with PWM, PWM dimming can precisely control the LED brightness, but also to ensure LED light chromaticity.

　　Bluetooth technology basics

　　Bluetooth is the founder of the Swedish company Ericsson, Bluetooth is a wireless data and voice communications open global specification, which is low-cost short-range wireless connection, based on the establishment of a special connection for fixed and mobile communication environment. Data sharing between phones via Bluetooth has become a common sense, will be transformed into a remote control handset tremendous convenience to people's lives.

　　Bluetooth radio work globally 2.4GHzISM (ie industrial, scientific, medical) band, supports full-duplex transmission, using IEEE802.15 protocol. Bluetooth device that is not even ready to use, anti-interference ability and easy to use.