Build a Pool or Spa Monitoring System

Anyone who has owned a hot tub knows that without keeping a close eye on the water with test strips and water test kits, a hot tub can quickly get green, cloudy, and unusable. A pool can often be just as hard to manage. Monitoring the temperature, pH, and ORP 24/7 and alerting you when chemicals need to be added is a valuable tool to stay on top of managing your water. This was my motivation behind the SpaSitter, an open source spa or pool monitor using a Nanode (an Arduino based network enabled node) and 's easy graphing API and triggers. Now you can always have easy access to your water conditions on your smart phone or the web. Set up email alerts to notify you when water conditions start to degrade.

The  SpaSitter is an open source, easy and simple way to get reliable and accurate readings on the current sanitation and chlorine levels of your hot tub or pool.  Monitor temperature, pH, ORP 24/7 and set up your own alerts with

Here are some benefits to Open Source Hardware and a great resource for more info.

Open source is great way to build things, there are numerous support articles on the web for building Nanodes and trouble shooting code.  There is a community of active makers in forums that are willing to help answer questions if you get stuck.  The hot tub monitor is open source so please feel free to copy and improve on the design.  We just ask that if you improve it, you share the new design.  If you make the design commercially, we ask that you pay a small royalty for supporting the projects continued development and community support.  We ask that you attribute the OpenSpaMonitor project and other that this project was build upon.  The un-spoken rules of open-source hardware business is a great reference.

Building your own products allows you to fix it when broken, the product shelf life becomes much longer when you can replace one broken part instead of the whole commercialized product.  The product can also become re-purposed easily into other applications instead of throwing it away at the end of its use.

Being able to calibrate and recondition the monitor on your own means the hot tub monitor or SpaSitter will last much longer than other devices currently on the market.  Using industrial probes designed for continued use means that there is virtually no maintenance, the gel filled reference solution never has to be refilled.

Customization is an amazing factor in open source hardware projects. There are many ways you can make the SpaSitter your own.   Change the source code to report to your own server.   Add a Twitter account to your hot tub or spa and have it tweet you.  Build an embedded event log that details your chemical applications and usage of your pool or spa. The list is endless.

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  1. This definitely is interesting thinking about building my own addition to my pool. Something that really stands out, that I like, is that you mentioned that the good thing about building your own parts is that it is easy to fix. That definitely rings true for the most part. I really like the idea of having some kind of monitoring system as well. Thank you for sharing.

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