About this Project

The hydrometric pendulum idea works equally well in a "float&anchor" configuration, allowing open water deployments.

The hydrometric pendulum idea also works in a “float&anchor” configuration: allowing us to also deploy them in open water environments.

Early in 2011 I realized that open source micro-controller boards had the potential to replace expensive commercial sensor units with cheap & cheerful DIY equivalents. In January 2014, I started this blog to record my attempt to build a simple flow sensor using an Arduino. The project has grown quite a bit since then, and my current goal is to create a robust underwater  logging platform, from pre-assembled modules, which can be adapted to a variety of environmental monitoring applications.

This ‘lowest common denominator’ approach means that any component in the build can be changed without requiring a significant re-write of the operating code.  My performance benchmark is at least one full year of operation on three AA batteries, and with that system as a foundation, I will build instruments that focus on a theme of water because of it’s crucial role sustaining us, and connecting everything we do to the natural world.

The current logger base unit. Many different sensors can be attached.

This is one of the current underwater configurations.  The three component  logger forms a generic base unit which supports many different sensor configurations.

It’s fantastic that anyone can learn enough to build something like this from scratch, and I hope that this blog is a useful contribution to the Makers movement; engaging people with environmental  issues and giving them a chance to actively participate as citizen scientists.  So if you want to start a project of your own, browse through my ongoing adventures from the place where it all startedand I hope something in there helps you out. There have been many successes and many failures along the way, and I still learn something new every day…

 NOTE: If you want to read “the story” of this device,  and you are not used to navigating the reverse chronological order that blogs use, you will find links at the bottom of some pages that look like this: <—Click here to continue reading—>
These links will take you through the pages in a somewhat linear narrative, skipping over most of the nerdy technical posts.  I assume everyone else* knows how to use the categories in the sidebar, or the search feature, to go directly to the information they are after. 

And for the real propeller heads out there:
 I am doing my best to make this blog a content rich source for others, so there are hyperlinks throughout the text to the best sources I have come across so far. But I am always looking for more, so your insightful comments are much appreciated! This is my first Arduino project…actually it’s my first real diy electronics project of any kind…

With support from the National Geographic Society / Waitt Grants Program

16 Responses to About this Project

  1. Grace Cagle says:

    Wow, I’m so happy to have come across this page. Thank you for your diligent documentation! I can’t wait to see how I can use this information. I especially enjoyed your writing on the inception of the project.

  2. cpadi says:

    Your blog is an outstanding source of technical information, ideas and links… Thanks for sharing!

  3. Dan Cross says:

    Wow, I can’t tell you how much I’ve been enjoying this blog. As a relatively recent “Maker” (and ham radio nerd) things like this have been extremely inspiring! Thanks for it and keep it up.

  4. Great blog. Motivated me to buy an Arduino and begin prototyping a pressure sensor for monitoring cave stream water depths. Curious: What temperature sensor would you recommend given your experiences? Thanks.

    • edmallon says:

      To date I have been working with I2C breakouts (Sparkfuns tmp102 & Adafruits MCP9808) and one-wire DS18b20’s. All give you 0.0625C resolution but the MCP9808 gives a reasonably decent ±0.25 accuracy. The DS18s take quite a bit of calibration because there is a large amount of quality variation, but they have the strength that you can hook so many of them to very long wires. This multi-drop aspect of the DS18B20’s keeps bringing me back to that sensor over and over again. To be honest, all of them are ‘just OK’ as most of the caves we work in have less than 1 degree Celsius of variation all year. But what I really want for the cave work is an affordable sensor that can give me ±0.1C accuracy and 0.01C resolution. RTDs and Thermistors can deliver that but I have not had a chance to play with them yet.

  5. jesadaph says:

    Thank You for Sharing Your Knowledge. Great blog , I’m never seen before.

  6. Christophe C. says:

    Thanks for your blog and sharing information. I’ll come back on it to search for Arduino information, power consumption reduction, sensors selection and epoxy pouring. For now, you just took 2 hours of my work day .. pfff.

  7. Mark Woods says:

    Great work!

  8. Jimmys says:

    Thank you! You are a big source of inspiration even to hardened engineers. The reading of the articles is a joy and also I learned a great deal for sensors calibration and what not. Also the density of information you provide is fantastic I truly consider this blog a Arduino university. If you need to deploy to Crete, I will be GLAD to help. Over a hundred caves in the island are waiting.

  9. koitoliver says:

    Thank you for this inspiring blog. Do you happen to have any experience on coupling the pro mini with ultrasonic sensor to log stage height?

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