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Comment by 2III7 | Hacker News Reader

I bought this moisture sensor for a gardening project

https://www.tindie.com/products/miceuz/i2c-soil-moisture-sen...

Haven't had the chance to try it out in soil yet, but reading the comments it looks promising. It uses capacitance instead of resistance and connects directly to the I2C pins of the Pi. So, easier to setup and should be more reliable.

On the software side I use Grafana https://grafana.com/

Not really made for gardening projects but its monitoring and alerting capabilities are pretty much perfect for this kind of application. Not to mention how easy it was to set it up on the Pi and get all (temperature, moisture, light) the sensor data in.

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Or.. you can use a $2 Arduino Nano clone, a 1¢ 10MΩ resistor and some aluminum foil strips to build one yourself.

http://playground.arduino.cc/Main/CapacitiveSensor

Thank you for that. I was really beginning to give up hope for the site :-)

...nope. This'll give you a nice little touch sensor but not much more than that. Try turning this into any sort of usable measurement of soil moisture as opposed to "there's wet soil on this strip of foil" and you'll run into a wall.

Reminds me of Cheesoid.

https://www.youtube.com/watch?v=B_m17HK97M8

Another, more polished, option is http://vegetronix.com. I've used their probes for years and can't believe they're not more popular.

They use capacitive sensing and they're enclosed and waterproof.

I highly recommend them.

$40 is quite steep compared to the rest of components usually used in such a project.

Have you had any fail yet? $40 seems like a lot until you add up replacement of failed units for the cheaper stuff.

I admit the price is steep, but it's worth it for me. They're more for a professional application than the hobby side of things.

I have found them to be reliable and accurate. No failures yet in about a year and a half.

I usually adhere to the old "you get what you pay for" mindset, so I have no problem spending more on something I can rely on.

Miceuz's work is excellent and this sensor in particular is on point. I've been using a handful of them with an ESP8266 as a wireless I2C master for the last year or so.

Thanks for the tip! I hadn't seen this.

Beware of the delivery time though. It took them 3 weeks to ship the sensor from Lithuania to Estonia :)

For pump and other peripheral control I plan on using an opto-isolated relay board. You can get one for really cheap and they're easy to setup with the Pi. Check this wiki on how to use the board in isolation mode.

http://arduino-info.wikispaces.com/ArduinoPower

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