LeoPhi USB enabled pH interface

Ryan Edwards met up with the DP crew at Maker Faire and he sends in this post on his experiments with open source water quality sensors.

For the last few years I have been creating open source water quality sensors. One of my other passions is Gardening and I had a need for pH and other (DO, eC) sensor interfaces for an Aeroponics setup I was creating. After not finding much on the market I decided to create my own, and as a result LeoPhi and MinipH were created.

LeoPhi is a USB enabled pH interface with an Atmega32u4 onboard. It allows someone to create standalone meters, or program it however needed.

MinipH is a very cost effecitve I2C pH interface meant to be added to projects very easily! It has a 12bit ADC and a fair amount put into the analog layout.

And while at the MakerFaire bring a hack dinner I showed off a DIY pH meter build and have a brief write up about it.

For those that want to start off from the begining and create their own interfaces I have a pH interface tutorial.

I plan on getting tutorials and writeups for my other sensors as the come online (eC and DO are next).

Visit Sparky’s Widgets for LeoPhi project info and code.

Via the contact form.

Join the Conversation


  1. Awesome, really great to see this get featured! Thanks for featuring my project DP!!
    Originally started back around 07ish it took me a long time to ramp everything up learning everything on the way! Just wanted to say thanks, off to my day job I hope these help some out!

  2. Awesome! I have been looking for pH (and other water quality) meter DIY ideas for my pool. Poor water quality can destroy a plaster or in-ground pool, to say nothing of making swimming unpleasant. I look forward VERY much to your other projects, and hope you will share your insights as you progress.


  3. It was an insight to me thanks! Did you though of measuring the oxygen content and temperature of the water for the safety of fish (aquarium)
    Will you mind if I know also the microcontroller part on how to interface and the coding procedures

Leave a comment

Leave a Reply to John Cancel reply

Your email address will not be published. Required fields are marked *

Notify me of followup comments via e-mail. You can also subscribe without commenting.