Water Quality Sensor

Developed during the Water Hackathon on March 23-25 in New York City, the water quality sensor is a multipurpose tool for collecting data remotely. This tool is rapidly changing and is being used as part of the on going research initiative called [DontFlush.me](https://web.archive.org/web/20160111004345/dontflush.me) (archived). This tool consists of an Arduino microcontroller, a set of water quality sensors, and a network connection module. As currently developed this tool uses a GSM based cellular module to send data via SMS. For this design a custom arduino shield was created. This shield allows the arduino to be powered by a 3.7v lithium ion battery. The shield includes a 3.3v to 5v setup circuit based on the Adafruit Mintyboost. Currently there are two versions of the shield. Both versions use the waterproof digital temperature sensor from Adafruit. The shields differ in the electrical conductivity probe they are designed to use. Electrical conductivity (EC) is basically a measure of water's purity. The more pure the water the less conductive. When pollutants enter water it usually causes an increase in EC. Lots of details about EC are available from the EPA site. The first probe is DIY. It was created using designs published in the book Environmental Monitoring with Arduino. This probe uses readily available parts from most Radio Shack stores. More details about this probe will hopefully be posted with permission from the book's author. The second type of electrical conductivity sensor is much more expensive but is lab quality. Its available from Atlas Scientific. Here is the shield designed for the Atlas Scientific probe. Connected between the battery and the Arduino is a solar charging circuit. And also use for [quality control systems](http://www.aquar-system.com/). This is connected to a 2w 6v solar panel. Both of these are available from Adafruit. The data from this sensor is uploaded to Pachube using a GPRS shield from Seeedstudio. The initial prototype was using a TCP/IP connection, which requires a SIM card with a data plan, but the Arduino code is poorly optimized for long durations. The second prototype is sending SMS messages directly to Pachube's beta SMS gateway. Here is the sensor all wired up in a pelican case with the solar panel on the top. ...

Author Comment Last activity Moderation
EdMallon "I had a project that needed some live data display, and looking for the cheapest low-power solution for our loggers lead me to the Nokia 5110 LCD. ..." | Read more » almost 6 years ago
Paquicamus "I have done many calibrations to correlate Conductivity vs TDS. One thing that I have found out it will only work for one Creek, river or any surfa..." | Read more » almost 6 years ago
warren "Awesome!!! " | Read more » about 6 years ago
MadTinker "Ran across this article that discusses at a high level the relationship between salinity, TDS, and conductivity. Reference . It specifically mentio..." | Read more » about 6 years ago
MadTinker "Confirm? Hmmm... well, I have two data points, both of which coincidently use the same multiplier on EC to get TDS. From discussions with folks wh..." | Read more » about 6 years ago
warren "@stevie - maybe this could at some point be a good kit for students to use? Pretty cool, @MadTinker !! Interestingly the TDS pen also converts to ..." | Read more » about 6 years ago
MadTinker "An quick update: The TDS sensor from DFRobots performs as describes. Very easy to connect to the MiniPearl logger. In general, it collects a voltag..." | Read more » about 6 years ago
Ag8n "You hit the nail on the head with auto correct. Good luck with your project. " | Read more » about 6 years ago
MadTinker "@Ag8n - yes, I saw the other discussion, but it had seemed to go on a tangent. ‘crazy’ @cfastie I think hits it right on the head (gotta love that ..." | Read more » about 6 years ago
Ag8n "There are several other previous questions that discuss this. But crazy is is correct, all tds meters are conductivity meters. One side note- ther..." | Read more » about 6 years ago
cfastie "I agree that the DFRobot TDS sensor looks like a useful device at a good price. My lame understanding is that this and other sensors which purport ..." | Read more » about 6 years ago
warren "I love this idea. Here are some leads on connecting a TDS meter to an Arduino, if that's what you're interested in: https://forum.arduino.cc/index..." | Read more » about 6 years ago
warren "wow!!! This is very cool. Here's an amazon link: https://www.amazon.com/s/?tag=duc0c-20&url=search-alias%3Daps&field-keywords=tds%20aquarium " | Read more » about 6 years ago
Ag8n "I checked Amazon. There are several tds meters that also do conductivity for a price of under $20. Since a scientific model lists for about $1000,..." | Read more » about 6 years ago
Ag8n "Sorry. Truncated the internet address: Https://www.hydroponics.net/learn/debate_over_ec_and_tds.php " | Read more » about 6 years ago
Ag8n "Check out: Https://www.hydroponics.net/lear All tds meters are conductivity meters, but according to the article, they may not all use the same c..." | Read more » about 6 years ago
Ag8n "I think it is. Was hoping someone was more familiar than me. Different websites talk about charge and others about conductivity, which can be two..." | Read more » about 6 years ago
gretchengehrke "Hi @Ag8n, Do you know how the aquarium TDS meter works? Maybe it really is just a super cheap conductivity meter? " | Read more » about 6 years ago
EdMallon "Thanks xose! Its been a long road, and we documented the entire process on the blog over time, including the mistakes. Now we are working towards..." | Read more » about 6 years ago
xose "Guys, all of you specially Ed, this thread is awesome! " | Read more » about 6 years ago
EdMallon "We have finally published: A Flexible Arduino-Based Logging Platform for Long-Term Monitoring in Harsh Environments http://www.mdpi.com/1424-8220/..." | Read more » about 6 years ago
EdMallon "I try to keep the blog tightly focused on the logger build details. But this year, I felt that I had to say something a bit more pointed about the ..." | Read more » over 6 years ago
EdMallon "Like a great Hollywood franchise I finally released the prequel to that "Configuring I2C Sensors" post from a few months ago: Adding Sensors to an..." | Read more » over 6 years ago
donblair "Hi @gretchengehrke! Sorry for the much-delayed reply :) and thanks for the comment. I, too, liked this approach -- basically, using the differenc..." | Read more » over 6 years ago