sun switch
sun switch circuit
The Sun Switch is a simple device that allows solar tracking to be added to solar cookers for practically no cost. The device is made possible by the photovoltaic properties of LEDs.
The sun switch can be built from readily available scrap computer parts. Suitable LEDs can be found in any old computer keyboard, drive chips, resistors, caps and pcb can be found in computer printers, DC motors can also be easily found in many scrap electronic devices. The sun switch can be made totally from recycled materials.
You can build the Sun Switch to fit any solar cooking oven. Common ABS plastic (plumbing) can be used to build the device but it can also be easily made from word or metal. The basic principle uses a vane which cast a shadow over the sensor LEDs. When the earth rotates the sensor LEDs are slowly exposed to the sun as the shadow tracks east. The exposed LEDs produce a voltage which serves as a logic input to a motor control chip. The motor is activated which rotates the sensor housing casting a shadow over the sensor LEDs switching off the logic input and turning of the motor. The whole process happens very quickly and can track the sun very accurately.
The sun switch uses very little energy and can be powered by a small solar panel of a few watts. You can view sun switch plans (a version made for a PV panel solar tracker) on my website Build a Sun Switch
Please feel free to edit this page and add details of any sun switches you build.