Solar Power – Project Curacao back to the
Tropics
Project Curacao is heading back to the Caribbean from the Frozen North(tm). We are sending it with a team of folks that are heading back to the island shortly.
What is Project Curacao?
Project Curacao is a solar powered sensor filled project designed to hang on a radio tower on the island nation of Curacao. Curacao is a desert island 12 degrees north of the equator in the Caribbean. It is a harsh environment with strong tropical sun, salt spray from the ocean and unremitting heat. But it is a beautiful place to visit and a real challenge to build and install a Raspberry Pi based environmental monitoring system.
Want to build your own Solar Power System? Check out the SunAir Solar Controller.
Project Curacao consists of four subsystems. A Raspberry Pi Model A is the brains and the overall controller. ThePower Subsystem consists of LiPo batteries and charge management. The Environment Sensor Subsystem has in-box temperature, outside temperature, luminosity, barometric pressure and humidity sensors. The Raspberry Pi Camera Subsystem contains a Raspberry Pi Camera and a servo motor controlling the cap (made from a Kitty Litter Container!) over the camera to keep salt spray off the camera lens.
It quit back on November 23, 2014 during a ham radio contest that was barraging Project Curacao with RFI (Radio Frequency Interference). We expected from the data in late November that the front end of the Arduino processors was ruined by the RF interference during a late November 2014 Ham Radio Contest (not their fault – we should have put a choke on the long sensor lines headed to the WeatherRack weather sensors). Basically, the RFI caused the Arduino to reboot periodically during the weekend before during another radio contest, but recovered. However during the next weekend, the Raspberry Pi SD Card was corrupted, probably by too many reboots because of the RF issues.
When we got the box back in our lab and opened it up, the interior looked very clean and the solar cells were perfect (thank you Voltaicsystems.com). However, the batteries had not been removed before shipment. The mounts were never designed for transport and the batteries came off the velcro strips and flopped around pulling wires off and generally causing issues. This damage was not hard to fix.
Modifications to Project Curacao
We first build this project in early 2013. Since then we have built many circuit boards, dramatically improved our solar power technology (SunAirPlus/SunAir) and acquired a 3D Printer for SwitchDoc Labs.
Arduino Battery WatchDog Solar Power Controller
1) We replaced the old controller and three INA219 current/voltage sensors with SunAirPlus (which contains an INA3221 3 channel current/voltage sensor) and reduced the power supply wiring necessary.
2) We replaced the broken camera mount with a 3D Printed mount. Much nicer and easier to make. No more superglue and soft plastic.
3) Tightened the wires and grounds throughout the box. We will do this again when the box reaches Curacao.
4) Purchased the chokes to reduce the RFI reaching the box through the long lines to the WeatherRack.
5) We replaced the AM2315 Outdoor Temperature and Humidity Sensor. The direct sun fried the Humidity sensor. Now in shade.
Software
We made some minor upgrades in the software. Updated to the latest version of Apscheduler and generally updated the software. We had to replace the SD Card. We are making an image of the card and taping it to the inside of the Project Curacao box so there is a spare with box in situ.
RasPiConnect Results
Our RasPiConnect Control panel received a few new buttons. One was forcing the Raspberry Pi to go and get new readings from the Battery WatchDog Arduino. Works like a champ. Note the first graph shows the Arduino Watchdog decide not to wake up the Raspberry Pi at midnight because of the cloudy days and the low battery voltage.
And the Arduino Watchdog is running like a champ!
