Sun Switch simple sun tracking electronic device

greenwatts.info The Sun Switch is a simple to make electronic device which can accurately track the position of the sun. It was designed for the Canuckle solar tracker project (www.greenwatts.info) but can be adapted to almost any application that requires solar tracking like solar ovens, solar lighting and solar heating. The device can be made for only a few dollars and the circuit is so simple it can be assembled by anybody.

Step 1 Its simple ... really simple

The Sun Switch sensor uses green GaP LED's to sense the position of the sun. When a GaP LED is pointed directly at the sun it will produce around 1.7 volts across the leads. By simply placing two or three of the LEDs in series you can provide enough potential to drive TTL logic inputs on a bridge driver. The bridge driver circuit itself is simple and very easy to build. You can use any bridge driver chip that has TTL (digital input control) and is suitable for the size of DC motor to be driven. Parts to build a Sun Switch, motors, bridge drivers and LEDs, can be found in scrap electronics or computer hardware. This instructable describes a sun switch built with a L6202 chip and a sensor built with 5mm GaP LEDs.

Comments

[lieuwe]

this waaaay to complicated, you could make this with just one light sensor(don't know the technical term for those) in a circuit which turns the motor forward when the light sensor doesn't get light, then use a crankshaft type of deal to move your mirror, and then place the light sensor on the moving part so that it only gets light when the it points a the sun(something with a slit in it) then when you thing isn't aimed correctly, the crankshaft will turn which will make the moving part scan the sky until it gets light from the sun, hmmm sounds complicated when you say it like this, but on paper its easier than this arrangement

[helpmonkey]

well you would think so but your arrangemnet will run into a few problems that are impossible to solve. If it is cloudy your device will continually scan, also attaining accuracy with your arrangment will be much more difficult... I have tried and the sunswitch was the only arrangemnet I could come up with to solve all of these issues... also I am working on a modification which will use a simple op-amp circuit to reduce the amount of LEDs required ... thnks for your comments :-)

[Eternal_Tristan]

I'm having trouble picturing how this works with the rays of the sun. Can you explain why the plate is mounted parallel to the last row of the west LEDs? Thanks, Tristan

[helpmonkey]

basically you need to think in reverse. The sensor LEDs drive the motors when exposed directly to the sun rays. Since the sun moves accross the sky from east to west a shadow will creep across the sensor in the opposite direction. As the shadow receeds the first row of west LEDs are exposed to the sun rays causing a west rotation of the tracking device therefore casting a shadow over the LEDs and the process repeats... you can check out videos on youtube or visit www.greenwatts.info for a better understanding of how this works...