Nearly all solar oven designs operate at peak performance only when directly facing the sun. The single critical shortcoming in the solar oven marketplace is the lack of an apparatus which will rotate your oven so that it always faces the sun and optimal performance is sustained for the entire cooking time.
Unless you are at home all day with nothing else to do, the necessity to manually rotate the oven is a significant inconvenience - no 'Set It and Forget It'.
I find that the commonly made concession is simply to approximate the mid point of the sun's path for a particular cooking time and leave the oven at that angle for the whole time; far short of an effective answer.
Zhu and Kim have offered a mere 18 calculations to use in order to find that correct angle:
A Super Solar Tracker is an easy to assemble circuit that drives a small motor which slowly rotates your oven on a simple wheeled platform as the sun goes across the sky. This solution is so simple that a 12 year old could build it with my plans in hand.
Oh yes, you could try to build a solar tracker from a 20 year old idea like the one located at:
The above .org design has only a trial and error method for adjusting the sensitivity of the photo transistor - blackening the lens by hand. Tedious indeed, having to regularly remove excess black based on the brightness of the sun that day.
The Super Solar Tracker uses a simple variable resistor which allows very fine control of sensitivity.
As well, there is no mention of the ability to turn the circuit off when there isn't enough sunlight for the transistor to successfully track. The Super Solar Tracker has a secondary transistor which turns off power to the motor in times of obstructed sun (with another variable resistor so that you can decide how sensitive that secondary transistor is).
As well, the above .org plans contain no precise list of which parts to use, nor where to get them. The total cost of parts for the .org plan is around $250 in adjusted dollars for the year 2007.
The parts for the Super Solar Tracker circuit (including the motor) can all be purchased online for as little as $30 from the a single retail chain electronics store, in either Canada or the United States. I provide a separate parts list for each country.
There is no need to drill large holes nor use belt/chain drives in order to move the oven as in the .org plans. Instead, a geared motor measuring 1" X 1" X 2" (included in parts list) can be fastened to a small wheel, which will rotate the oven when turned on by the Super Solar Tracker circuit. And it all can operate on a single 9 Volt battery instead of up to 10 AA batteries.
The Super Solar Tracker plans come complete with step by step directions, a 3 part electrical assembly diagram, including views of the parts and how they are connected to each other, the complete list of parts, their specifications and prices, as well as the contact information for ordering the parts from an online/retail electronics store in either Canada or the United States which ships worldwide. Also included is a mechanical layout diagram which details how the Super Solar Tracker is wired to the motor, as well as a template plan showing placement of the wheels and pivot point for the base of the oven, for easy construction.
Finally, a REAL ‘Set it and Forget it’ solution.