SDI-12 Buddy Bluetooth

SDI-12 Buddy Bluetooth is my latest product that helps researchers and growers like you to get your tasks done with ease. This device connects an SDI-12 sensor to your Android smartphones or tablets via Bluetooth. You can detect the sensor, read its values, including calibrated values per manufacturers’ formulas or you custom calibrations, change its address, and more!

Use cases:

  1. Setting up a data logging sensor node. Test each sensor and assign a unique address.
  2. Troubleshooting an existing data logging sensor node. Test each sensor for correct responses.
  3. Spot check your field or grow room. Carry a sensor and read its values at different locations.

If you wish to log data on the long run such as using this device as a wireless data logging node, this is not the right use case. The Serial-over-Bluetooth profile used by this device means it can’t go to sleep between data points so it must stay awake and the battery will drain after several hours.


  • Compatible with SDI-12 sensors with my SDI-12 core technology that has been used and tested for the past decade on numerous sensors by countless users
  • Powered by 2 X AA batteries
  • Internal boost circuit provides 12V to power the SDI-12 sensor
  • IP67 water and dust proof rugged enclosure with waterproof button and cable gland
  • Bluetooth connection to Android smartphone and tablets with a free app
  • Calibrated readouts and raw readouts (more calibrations will be added to the app)
  • Custom calibration curve
  • Connectivity is indicated on the power button’s ring illuminator
  • Optional mounting flange kit

Android app download:

I have applied for a Google App developer’s account and have the app as an internal release for testers for now. If you’re interested in testing it, here is the link:

If you just want to download the app outside Google Play Store, here is the .apk. You may have to tweak your app installation settings to enable installing apps from unknown source if you download this .apk.

Liudr SDI-12 Buddy Bluetooth Android app V 1.8

Liudr SDI-12 Buddy Bluetooth Android app V 1.5

Here are some photos of my first prototype:

Front view
Side view of power button and stereo connector
Android app

I have just built my first printed-circuit-board prototype. The flashing power button’s blue LED ring indicates the Bluetooth is not connected. A steady blue means it’s connected to your phone. In this small build, I’m only supplying to a major client. I will be releasing this soon.

I have built in enough protection so you can swap sensors without having to power the device off. If your sensor doesn’t come with a 1/8″ (3.5mm) stereo plug, my SDI-12 Buddy comes with an adapter like this:

The pin out is:

  • Tip (left channel) is power
  • Ring (right channel) is SDI-12 signal
  • Sleeve is GND

Where to buy:

Currently SBNV consulting LLC is selling the product exclusively for me: