Managing solar power systems with SunAir boards

Gathering Data

The next board project at SwitchDoc Labs is a version of SunAir that will be used in developing systems. It is a more expensive board, because it contains additional data-gathering hardware – specifically, a high-quality I2C four-channel AD converter for the photoresistors and an I2C three-channel IC for measuring currents and voltages. This allows the user to build a fully instrumented solar power system to really generate a lot of data, in addition to supplying space for an L239D motor controller.

SwitchDoc Labs has also licensed RasPiConnect from MiloCreek [22] to provide inexpensive control panels for SunAir and SunAirPlus. They will be available for $2.00 on the Apple App Store in February 2015. If you already own RasPiConnect, you will be able to download the XML configuration file from GitHub [4] under the SunTracker repository.


SunAir and SunTracker turned out to be enormous projects. I was expecting to spend a little more than about four weeks of work, but it has turned into three months and I'm not through yet.

I had to send the SunAir board to the manufacturer three times and spend a great deal of time in careful debugging to figure out why the board was not performing up to the complete specifications. Now, however, that part is done, and I am looking forward to building several new projects with these boards.

Additionally, I have had the Project Curaçao box shipped back to the frozen north, and I am refitting the solar power system in the box with the new, more reliable SunAirPlus boards.

SunTracker is morphing into a new project called SunRover, which will be a semi-autonomous solar-powered rover based on an Arduino and Raspberry Pi. With any luck, it will be running around the Caribbean in June 2015, but I need to make sure it can see cliffs. You can look for the SunRover project in a future issue of Raspberry Pi Geek magazine.


  1. Curaçao:çao
  2. "Sizing a Wind Turbine to Power your Raspberry Pi" by John C. Shovic, Raspberry Pi Geek, issue 04, pg. 8,
  3. "Mixing Wind Turbines with the Tropics" by John C. Shovic, Raspberry Pi Geek, issue 05, pg. 60,
  4. GitHub:
  5. AA batteries:
  6. D batteries:
  7. Arduino battery watchdog:
  8. "SwitchDoc Labs: Real-Time Clock" by John C. Shovic, Raspberry Pi Geek, issue 07, pg. 86,
  9. "SwitchDoc Labs: Watchdog Timer" by John C. Shovic, Raspberry Pi Geek, issue 09, pg. 86,
  10. SunAir solar power controller:
  11. CN3065 datasheet:
  12. ISL97516 step-up regulator:
  13. "Eliminating noise from sensor readings on Arduino with digital filtering" by Elco Jacobs,
  14. "Drive a servo motor with the Raspberry Pi's PWM1 peripheral in C++" by Hussam Al-Hertani,
  15. "SwitchDoc Labs: MouseAir" by John C. Shovic, Raspberry Pi Geek, issue 05, pg. 38,
  16. "Control your motors with L293D and Arduino" by guibot,
  17. "Driving stepper motors with the L293D" by Rob Turner,
  18. Code and schematics for this article:
  19. SunTracker in action:
  20. OpenSCAD:
  21. "3D Print Your Mouse" by John C Shovic, Raspberry Pi Geek, issue 08, pg. 54,
  22. MiloCreek:

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