Tunable Lamp Prototype with Adjustable Color Temperature

To develop an energy efficient lighting system is the purpose of this project which does not only produce light but comes with a color and spectrum that has a positive influence on the mental and biological state of a person.

A low cost ATtiny44 microcontroller was used to design the module which has 4 PWM outputs used to drive 4 current sources in which LEDs are provided with current. A PWM controllable current source that can drive up to 1A is represented by the ZXLD1360 which is a continuous mode inductive step down converter. The step down converter is a more efficient way of driving the LEDs from the microcontroller although a more simple way is to use a current limiting resistor and a PWM’d FET but a lot of energy in the resistor can be wasted.

The four high power LEDs are used by the system in order to create different light frequency. Because of the distance between LEDs, the lamp provides funny-colored shadows. The drivers produce a very slight buzzing noise but the total brightness is enough for normal desk light. Each LED channel will have switching current driver.

Rest of the project