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Water Sensors

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Many people interested in measuring various water quality parameters that are relevant to environmental health in low-cost and accessible ways. Many have been working on low-cost, open-source sensors for water chemistry and physical properties, and there are also several commercially available water sensors and analog tools that can measure relevant water quality parameters.



Often, electronic environmental sensors are just one part of a system that includes:

And we also have to consider:

It's hard work writing good documentation. Let's team up and share as much of the above as possible -- many of these steps are either not device-specific, or are at least very helpful if written in a way that supports use across projects.


Getting started

If you have never used an electronic water sensor before, try the Coqui project, which is specifically designed for folks who are just starting out.

Build a Coqui - a simple device to read a sensor via an audible tone.

The Coqui is also a stellar example of how to document a project. (above photo by @akshaya)

Choosing Sensors

Often the first step is to look for a sensor for what you're hoping to measure. Below we're collecting info on different kinds of water quality sensors, and their:

  • cost
  • sensitivity/accuracy
  • links and documentation

Can you afford a sensor? Can it detect what you're looking for? Where can you learn more about it?

And here's a longer collection of many different sensors (add to this list here!):

See and edit the full spreadsheet here

To be added

Are there others you're interested in? Please add them to the list here and to the linked Google Doc! (below are some not listed above yet)

  • transparency
  • chemical oxygen demand - COD
  • phosphate
  • total dissolved solids - TDS
  • Hardness
  • Lead
  • bacteria
  • fluoride

heavy metal

[prompt:text:ie temperature]


Title Author Updated Likes Comments
Any experience with knockoff temperature sensors? @wln215 over 4 years ago 1
DFRobot Turbidity Sensor Troubleshooting @mimiss over 4 years ago 5
Pros/cons to cheap handheld water meters for pH, TDS, conductivity? @warren almost 5 years ago 3
Dissolved Oxygen Testing and Citizen Science @belkinsa over 5 years ago 7
Are there any DIY equipment that measure dissolved oxygen levels in water? @belkinsa almost 6 years ago 6
Substitution for conductivity meter @Ag8n over 6 years ago 7
Have you encountered either success and/or problems utilizing water quality sensors? If so, can you share your specific experience? @gilbert over 6 years ago 0
Where are places (online) to look for off-the-shelf water sensors? @warren over 6 years ago 1
How do you account for signal drift with sensors in the field? @gretchengehrke almost 7 years ago 1
Can commercially available water sensors work with DIY data loggers? @gretchengehrke almost 7 years ago 2
What information do I need to assess if a data logger and sensor will be compatible? @gretchengehrke almost 7 years ago 3
How accurate are KnowFlow probes? @rockets about 7 years ago 3
Sensor: ORP versus PH @MadTinker about 7 years ago 2

Connecting sensors

Most of the data loggers on this site are Arduino-based (#arduino) while some are Raspberry Pi-based (#raspberry-pi).

Vernier has a lot of good resources on connecting their Arduino-compatible sensors, with example code:

As we build out resources for connecting different sensors or different types of sensor interfaces (i2c, analog, etc), let's think about how best to list those guides and support materials here.

Help add activities below for connecting specific sensors to different data loggers, and pitch in on researching how these connect here.

Purpose Category Status Author Time Difficulty Replications
Nothing yet on the topic "connecting-sensors" -- be the first to post something!

Activities should include a materials list, costs and a step-by-step guide to construction with photos. Learn what makes a good activity here.

Analog methods

Even though this wiki page is labeled "water sensors," the most accessible modes of measuring water quality parameters are often analog, non-digital methods where you directly observe water (e.g. using a secchi disk to assess turbidity) or collect a sample and test it with a visual method (e.g. color-change pH strips). Several analog tools are included in the spreadsheet, and please add more!

Hybrid approaches and enclosures

In some cases, it may be possible to couple a commercially available probe sensor with a DIY data logger (such as the Riffle, and an water-tight enclosure to create a lower-cost deployable sensor. Deployable sensors can be extremely useful for long-term monitoring, monitoring in places that are difficult to access frequently, or to document fluctuations in water chemistry with greater temporal resolution.

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