“Wait,” I hear you say, “didn’t you already bore us enough?” Well yes, but I haven’t come close to exhausting soil moisture sensing techniques. Lucky, lucky you…
Actually, I mainly forgot to cite my sources and give some handy links to more information! So rather than a thousand words on the many joys of capacitance sensing, here’s a link dump of some resources I found but didn’t mention last time.
- SOWACS “Soil Water Content Sensors and Measurement” Yes, a whole website dedicated to sensing soil moisture. No, I have not set this to be my homepage (yet).
- Wireless, Solar-Powered, Acoustic Wave Soil Moisture Detection System I’ll be real honest, this technique looks impractical to me – using an audio pulse to probe for moisture levels and using multiple emitters and detectors to cover the whole area. Then again, the technique isn’t very well documented compared to the hardware to implement it. I’ll be taking a look at this again.
- Soil Moisture Circuit Nothing all that new here, but I want to point it out for using a shunt ammeter to boost the level to 0-5V.
- Moisture Level thread on Parallax forums This has been a great resource for finding pages + resources, such as…
- BodenFeuchte sensor In German (link is to google translated version of the page) – another capacitance based sensor, using a slightly different design and oscillator circuit. When I go to investigate capacitance testing, I hope to test this circuit out.
- Wikipedia Moisture Sensors This is not a great page, I may be contributing to it. There is also Moisture Analysis which is more generic.
See, that wasn’t so bad?