Update on Project Curacao – Trouble in Paradise

August 17, 2015 AM2315, Arduino, Arduino Software, Pi Camera, Project Curacao, Projects, Raspberry Pi, RasPiConnect, SwitchDoc Products

Update on Project Curacao – Trouble in Paradise

Project Curacao has now been deployed for ten weeks in the Caribbean heat 3500 miles away from SwitchDoc Labs.   The box has been operating extremely well but an issue has again cropped up in the past week.

What is Project Curacao?

Project Curacao is a massive Raspberry Pi/Arduino solar powered project first published in MagPi magazine. It was first deployed in March 2014, lasted until a RFI (Radio Frequency Interference) incident in November 2014, came back to Washington state

Solar Power
Project Curacao Box – WeatherRack in Background

for a refit and is now back in the Caribbean.

Project Curacao uses the following SwitchDoc Labs products:

There are two independent power systems on board.  Two solar panels connected through SunAirPlus for the Battery WatchDog Arduino and three solar panels for the Raspberry Pi A+ in the box.   The new issue is with the solar panels and the Raspberry Pi A+.

Solar Panels and the Raspberry Pi

Project Curacao uses three VoltaicSystems 3.4W solar panels for the Raspberry Pi A+  to charge up a 6000 mAh LiPo battery through a SunAirPlus solar power controller.  Everything was working very well for the first four weeks, then we saw the current coming in from the solar panels during mid day drop to less than 1/3 of the previous value.  This has now happened several times.  The wire is connected and then something happens (wind gust?  See below) and it drops off againg.   The BatteryWatchDog Arduino was picking up the lower battery voltage and shutting down the Raspberry Pi (safely) and turning off the power supply because of the lower power available.   That part of the system was working perfectly.

Until the wind (see the chart graph below – we are now thinking that it is gusts of wind that is shaking the box and making the wire connect/disconnect) blows again, we will only see the box every couple of days when the Arduino deems the battery to be in good enough shape to boot up the Raspberry Pi.  See the instantaneous solar power on the Raspberry Pi pi.  Only 23 ma.  We are heading for a power shutdown on the Raspberry Pi, where the Arduino is still getting over 500 ma.

Later on in the week, another gust of wind (or a bird!) caused the solar panel connection to reform and we are back operating at full power.

So What Happened?

Take a look at this set of values from last week from the RasPiConnect control panel:

IMG_0985

 

See how on August 5, 2015 the current from the solar panels dropped to ~100ma from a maximum of ~800ma the day before?  After looking at the real time values showing on the lower part of the screen for a few minutes it was obvious what had happened.   We had lost connection with the two solar panels connected to the Raspberry Pi on the front of the box and only the top panel was generating power.   We were sure that it was a loose connection, but from 3500 miles away, there was not much we could do.  The wire is clearly very, very close to making connection.  Every couple of days it reconnects (heat, wind, vibration, birds?) and we have good power for a few days as you can see from July 16, 2015 on the graph above.

That is what a loose wire looks like from 3500 miles away.   We have a person visiting the box in late September 2015 and we will ask them to open up the box and tighten the wires for those two solar panels.

From a system perspective, the box is doing exactly what it should be doing.  Changing the box behavior according to the power available.  In the log files, you can see the Battery WatchDog Arduino refusing to start up the Raspberry Pi in the morning because the battery is too low.  Very cool.   The chart below shows the Weather Rack data coming into the Raspberry Pi.  Why are there gaps?  It is because the Battery WatchDog Arduino is gathering the weather data in a FRAM memory on the WeatherPiArduino board and relays it to the Raspberry Pi after the Raspberry Pi boots up.  However, the FRAM is only 32Kbytes and so after a few days it fills up.

 IMG_0986

A Picture of Paradise

We will end this post with a great picture of the Caribbean hot off the PiCamera in Project Curacao.

IMG_0987