Tuesday, June 16, 2015

2015-06-14: First Week of Arduino Data

I walked out to Green Hive on Sunday in between rain storms.  I popped the lid, pulled the SD card walked it into the house and downloaded the data.  A quick return trip to the hive and I placed the card back into the Arduino and hit the reset button.

My main purpose in making the Arduino solar powered is to see if it will be able to run continuously.  So, I'm looking for gaps in the data or any other unusual behaviors.

Here is a link to the Excel spreadsheet with the data

First thing to highlight is that I set up the Arduino on June 6 and it ran until June 12.  I pulled the memory card on June 14.  It was cloudy and rainy during the week.  So, once the battery dropped below a certain voltage, it could no longer power the Arduino.  I'm curious if the solar panel will be able to charge the battery back up while the Arduino is still drawing power from the battery.  And if so, how many full sun days would that require?

According to the specs on the panel, it outputs 330 mAh @ 6v. 

The battery has a 2000 mAh capacity so by my horrible math skills, it would take right around 6 hours to fully charge the battery.  Of course, that is in full sun and without a power hungry Arduino stealing energy from it!

The second thing to highlight is that I think one of the sensors is not measuring very well.  The external sensor seems to measure outside of the norm.  I pulled some historic data from weather underground and plotted their recorded high and low for temp and humidity as a base line.  The data often has some wild swings above and below those values.  The sensors I'm using are not meant for outdoor use, so I protected the external sensor with a plastic cup with a few small vent holes drilled in the side.  I also knew it might be sitting the sun so I painted it white to hopefully mitigate that temperature swing.

So either my protective housing is backfiring on me and trapping humidity or the sensor is not working well.  At this point I'm guessing it is the former.  If you look at the chart you can see the humidity spike to 100% almost every single day.  Maybe there is even condensation forming on the sensor.  I may have to look at something like this https://www.sparkfun.com/products/11050 to get some better readings.

It has been a fun project that has made me learn a lot.  I'd really love to be able to measure the hive weight and maybe even noise frequency!  Maybe some day.

As always, thanks for reading!


  1. Apologies, but it appears that if you view the Excel document just in Google that it renders it in a bunch of split pages. You may need to download the document and then open it in Excel to get it to look correct.

  2. I just read an article on humidity in the hive:


    The key sentence I read is this
    “During the brood rearing period median levels of humidity in the nest of a healthy strong colony is between 50% and 60%. It is rarely found to be below 40% and above 80%”

    Looking at the Arduino data, the humidity from the sensor in the brood nest is almost always between 50 and 60%!!! Awesome!

  3. Thanks for all the links, though I never opened it all yet. More power!

    1. Yes, there always seems to be a need for more power =)

  4. Really interesting data. I'm with you in guessing that the exterior sensor protector is the problem. It'll be interesting to see what happens when you take it out of the jar.

    1. I'm thinking the internal sensors are probably more important anyway. The external is really for a base line and comparison so maybe it isn't that big of a deal. I'm wondering if it might be more fruitful to try and measure sound frequency instead of messing around with one temp/humidity sensor.