Open Source Aquaponics
~ Reconnecting with Food
Geodesic BuildingGeodesic_Building.html

The acoustic sensor I’m using as a sump depth gauge has met with limited success.  It is quite the fickle sensor and is probably a result of the humid environment it is in.  Periodically it decides to quit working with no apparent reason or indication of cause.  Given this unreliable nature, I wouldn’t recommend this type of setup for others and will likely move this sensor to another project or to storage for a future project.  
Comment on Facebook or Gimme Feedback!

I wanted to find a way to keep tabs on the water levels in the sump to see how flow rates and temperature may affect transpiration rates in the plants.  Measuring the amount of water continually along side the temperature sensors will certainly help me figure that out.  It also will allow me to instantly know if my water is getting too low and potentially causing problems with my pump.  So, I looked at getting a liquid level sensor, but they're not very long so they have limited conditional use.  I decided I would try building my own liquid level sensor using an ultrasonic range finder which can work over greater distances and is less expensive.  After researching various options in sensors I chose the least expensive one I could find that would meet my desired parameters in terms of distance, simplicity and cost.  I chose a LV-MaxSonar - EZ4 (Part #MB1040) from Sparkfun electronics.  You can get is here…  if you'd like to try building a similar setup.
I tried mounted the sensor in various ways with respect to the barrel I'm using and found the signal noise within the barrel (lots of splashing from returning water lines) created too much distortion and I could not get stable readings.  I ended up mitigating the problem by inserting a 2.5 foot long x 3 inch PVC pipe into the sump and mounted the sensor at the top facing into the tube.  I then cut a piece of wood to match the inside of the pipe and have that floating on the surface within the pipe to give a more solid surface to reflect the ultrasonic sound waves more consistently.  
Wiring the Chip: The sensor chip was extremely easy to wire up and worked immediately on my first attempt! :)  For basic use anyways it only needs connections to the ground, power (~ 3-5 volts) and an analog line to take periodic readings.  Analog readings were then cross-referenced against data collection from the sensor at different distances.  From that I could apply a calculated coefficient factor to convert the analog reading to a distance.  
For example… at 24 inches I obtained a reading of 41 so I simply multiply every reading ( $reading ) I obtain by 24/41 or 24 * $reading / 41 or simply multiplied my readings by 0.5854 to get a value in distance (inches).  To get my actual depth reading I subtract my actual distance from the depth of the barrel (36 inches).  I can then plot these on my temperature graph as well as run statistical analysis to determine correlational aspects of water use with temperature and light exposure.

So far I've been able to obtain consistent readings over the past week or so and have been able to re-install the center pedestal without considerations for having to move it regularly. :)

Comment on Facebook or Gimme Feedback!

I've been working on setting up a database for others to use in processing Arduino data, but the instability of the Arduino sensors/wiring gave me a lot of grief so I put that on the back burner for now.   It took me several days to figure out that I needed to adjust my pull-up resistor in my circuit to be able to get the proper voltage for  consistent readings from my array of one-wire sensors.  What worked fine before suddenly didn't work and I couldn't figure out what was going on.  Electronics is definitely a love-hate relationship for me.  It's awesome when it works, but oh so frustrating when it doesn't!
Comment on Facebook or Gimme Feedback!

Spent much of today (and part of yesterday) re-wiring the greenhouse to increase automation services.  Unfortunately the Ardunio wiring for the sensors is not forgiving at all and I spent a great deal of time troubleshooting.  No mistakes are allowed as this follows the typical GIGO computer rule (Garbage In, Garbage Out)!  
I did, however, manage to successfully move my light sensor so I can now get a better idea of the light levels within the greenhouse vs my office window.  I have one sensor that is still giving me trouble so I’ve disabled it for now and will have to set up another for the outdoor air temps.
What I’d really like now is to setup a pH sensor for the fish and an underwater webcam so I can keep an eye on this where ever I am!  Perhaps when more funds and time allows...
Comment on Facebook or Gimme Feedback!

One of my goals is to automate as many processes as possible to ease the management of the system and avoid catastrophic failures that can result in unexpected changes such as running a pump dry or temperatures going haywire.  The fish requirements drive the system in terms of water chemistry and properties as they are much more sensitive to and dependent on the parameters of their environment than the plants... especially in terms of acute change.  So, I intend to automate temperature controls to regulate air and water temperatures, water flow cycles, send alerts in the event of power failures or low water levels, and monitor chemical properties of the water such as pH, temperature, etc. to maintain as much control over the system as possible with as little effort as possible.
To meet these goals I have been researching and learning the Arduino programming language and Arduino Uno board wiring configurations.  As of May 2012 I have accomplished collecting daily data on temperature from six different temperature probes installed in various locations and daily light readings in 40 second increments.  I have also created a database for data-tracking, graphing and statistical analysis which has been tremendously useful in determining if my ideas on thermal mass storage, door configuration, foyer, etc. are working as intended vs. “neat ideas.”  
Below are a couple of graphs showing the various temperatures throughout the day and their relationships to each other, various conditions and the light cycle.  Click on the graphs to see details and use your browsers “Back” button to return to this page...

Comment on Facebook or Gimme Feedback!

If you like what you see here... please click “like” below and share this site with others you feel may be interested.