Project Curacao2 – A Short Repair Trip
Our CTO, Dr. John Shovic, is heading down to Curacao for a few days to repair Project Curacao2 and meet with business partners. He claims that he is only unscheduled for two hours on this trip, which he intends to spend on the beach.
On October 5th of 2018, Project Curacao2 quit charging the batteries from the Solar Panel system and then said goodbye. How did it say goodbye? By sending an email (shown below). Project Curacao2 had been down and operating solo down in the Caribbean for over 3 months and was behaving very well.
It emailed Dr. Shovic about 2:55am with this sad news. This is a normal thing to for the Raspberry Pi to do if the Pi figures it can’t make it on the battery powered and so it emails us that it is shutting down. However, in this case it never booted up in the morning when the sun came up again and started the batteries.
This was the last picture (from the night before) that it emailed me. When this picture was taken the solar panels were still putting out power normally, although at this time of night it wasn’t much power , only 29mA coming from the panels, while we were pulling 437mA out of the battery (BV=3.61V/BC=437.20mA/SV=4.58V/SC=29.60mA/sun). Almost time for the Pi to shut itself down and go to sleep (3.5V is the night night voltage on the battery).
What Happened to Project Curacao2 in Paradise?
Our previous repair trip was to replace part of the solar power system (what did we think the problem was? See this posting). We had decided that because of sun angles, we had charged up the batteries and the resulting high voltage from the panels had fried the solar power controller. Now with this new issue, we are thinking that the box got too hot and during a high current recharge (read middle of the day) it went over the max temperature specification for the solar controller chip. While this doesn’t make total sense (the controller chip is supposed to have a thermal shutdown) the 5V power circuity or even the USB Power control chip could have also failed. We will take the board back with us to do testing to figure it out. We don’t think it was the Raspberry Pi because it said goodbye properly.
The Repair Trip
We packed up all the materials that we thought we would need to fix our problem as hypothesized. We will be leaving on Sunday, November 18th, 2018 and will arrive at the Project Curacao2 site about 9am on Monday, November 19th, 2018. We will be providing updates on Instagram (@switchdoclabs) and on Facebook. We are all packed up and ready to go! Along with a little light reading for the plane, “Python For Data Science”.
What is Project Curacao2?
Project Curacao2 is a redesign and rebuild of the Project Curacao environmental monitoring system that was running down on the island nation of Curacao in 2014 and 2015. We took it apart when we got down to the island and debugged the failure. It turns out what finally killed Project Curacao was the main LiPo battery on the Raspberry Pi had died. The Arduino watchdog time was happily running away, but couldn’t wake up the Raspberry Pi. We replaced the battery and the Raspberry Pi booted right up. We brought the SD Card and a variety of parts back to the Labs for analysis.
The project Project Curacao2 consists of two LoRa transmitters based on a Mini Pro LP and a Raspberry Pi Zero powered base unit. Lots and lots of sensors! All solar powered.
- Part 1 - Introduction to Project Curacao2 and the LoRa WXLink Feeder Stations
- Part 2 - First LoRa WXLink Feeder Stations Report
- Part 3 - Testing the LoRa Range
- Part 4 – Initial LoRa Range Results
- Part 5 – Final LoRa Range Results
- Part 6 - Raspberry Pi Zero Base Unit Build
- Part 7 - Flame On! Initial Base Unit Tests
- Part 8 - Solar Power Management System
- Part 9 - Ready for Deployment and Status
- Part 10 - PC2 in the Caribbean! Repairs and Testing
- Part 11 - It Lives! Deployment and Initial Results
- Part 12 - One Month of Results from Paradise
Below is a comparison shot of the original Project Curacao box (on the left) with the new Project Curacao2 box on the right. You can see from this picture the advances we have made in three years. The new Project Curacao2 box is wired together almost entirely using Grove Connectors. We have also designed and integrated new solar power controllers, wiring schemes and, in a big design decision, removed the Arduino Battery WatchDog. We found the reliability of our new solar power control scheme and power reduction techniques made the single computer Project Curacao2 possible.
