Sun Tracker - Design Details
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Here are the design details of a single axis solar tracker. It is an active tracker, designed for use with solar cookers or beeswax extractors, that uses electronics and a single drive wheel to follow the sun from East to West.
The choice of the drive motor is important. It needs to be low powered and be able to move a solar cooker or beeswax extractor, which can be quite heavy. With assistance from Stan Wells, we chose a very low geared motor. Its specification is listed below. It takes very little current, has a very hight torque and is reasonable priced.
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DC Worm Gear Motor; Rated Voltage: DC12V; No-load speed: 0.6RPM; Rated Torque: 25kg.cm; Stall Torque:53kg.cm; Rated Current: 0.09A;
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The tracker uses 2 small solar panels at right angles, and they are wired such that, when they are pointing exactly at the sun, the voltages they produce cancel each other and the result is zero. However, if one panel receives more sun than the other, then there is an imbalance, and a small voltage is produced. This voltage is used by the electronics to move the motor, until there is no voltage.
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The custom designed electronics uses a PICAXE microcontroller to monitor the 2 solar panels and operate the motor to track the sun. The schematic is available here and the software flowcharts are shown here.
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The Sun Tracker assembly consists of the following components. Follow the links to the source or make your own where its marked DIY.
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1. Large wooden platform to stand the Solar Cooker or Beeswax Extractor (DIY)
2. Castors of a suitable size and a wooden wheel to attach to the motor (DIY)
3. Motor, mounting bracket and flange coupling connector.
4. Main module with solar panels, electronics and battery.
5. A long wooden pole to fix the main module to (DIY).
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A custom designed main module with electronics, solar panels and battery in a suitable enclosure is available from SF Innovations. It has a cable that one has to attach to the motor to complete the control circuits.
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The motor and fixings is also available from SF Innovations.
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For an alternative solution, please have a look at our blog post here from August 2024.​​​​​​​​
