Solar Power update on the Pi

[faraday]

I just posted new results on Solar Power on Project Curacao. It's still working after 4 months!

It uses three solar panels and two processors (Raspberry Pi and Arduino) and a whole bunch of sensors.

http://www.switchdoc.com/2014/07/solar- ... i-results/

Best regards,

Faraday

[hampi]

I have been following the project Curacao on the MagPi pages. I started a similar but less ambitious project @RPiAOne last April. I am testing it at home backyard. I try to determine how much computer time the sun allows me in the long run. Last week was quite generous while this week is rainy and energy production is much less. No graphs yet but just simple semi-automatic summary tweets. The WiFi connection is quite poor in the place that the @RPiAOne is located now and the network is down most of the time.

[faraday]

Hampi,

Very cool. Post some pictures. Regarding the WiFi connection, I would use a cheap WiFi antenna that will get you a solid connection. Pringles Can, Coffee Can or Wok (metal dish) all will probably fix your problem. In my case, I'm just close to the WiFi router. It's through a metal roof and rebarred concrete but it's only about 10 meters away.

I use the Arduino to measure the Raspberry Pi's battery level and it shuts down the Pi when it gets too low. How are you turning the Pi on and off? I had issues with the Pi coming up after a low battery condition. Now it's reliable. I send an interrupt to the Pi from the Arduino (which causes the Pi to do a "sudo shutdown -h now") and then after 3 minutes, the Arduino cuts the power to Pi with a relay.

Here's more Solar Power information (Part 2 of 3) from Project Curacao.

http://www.switchdoc.com/2014/07/solar- ... results-2/

Obviously, I love graphs.

Faraday

[hampi]

I have been thinking about an antenna, but I try to get permission to place the RPiAOne closer to the router first.

I am recycling my one year old DIY power supply project here. The switcher LM2576-ADJ is turned on/off from a PIC microcontroller. This is an economy version with easily available parts. Should be possible to build anywhere in the world. For that reason and to save every microamp in sleep mode the voltage measurement has a large error. For example yesterday 12.2 V was measured from the PIC while the real voltage was 12.4 V (60 % vs 80 % capacity left on battery). Could probably do some (more) fuzzy control to mitigate that.

In my case the service (daemon) pipicpowerd calls the

shutdown -h now

for immediate shut down and power down or

shutdown -h +5

if only 40 % of battery capacity is left. This allows quick login before system goes down.