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Water Quality Sensor
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 "It's been a while so I thought I would post a project update to Public Lab 1) We had another successful fieldwork season, marking the deployment o..." | Read more » almost 8 years ago
EdMallon "Despite my zeal for the project, I have tried not to bomb everyone here with the many incremental updates as I go along. But I think I might have p..." | Read more » over 8 years ago
mathew "WARNING: do not, under ANY CIRCUMSTANCES get distracted by searching e-bay for vintage Hygrothermographs. " | Read more » over 8 years ago
donblair "Also: how hard would it be to rig up some sort of 'pen' that connects to a 555 and writes out a 'record' of the conductivity on some physical mediu..." | Read more » over 8 years ago
donblair "ZOMG that's brilliant. I'm going to try to bring the materials required to do a rough prototype of this to Plymouth -- but anyway shouldn't be hard..." | Read more » over 8 years ago
mathew "Yes, exactly! I would love to see an analog "retro edition" riffle with a microcassette recorder and a 555, maybe in a really nice Ball jar. " | Read more » over 8 years ago
warren "Wow, i'm not sure I follow all of this, but is one potential advantage of the 555 that we could even skip the arduino entirely, if, say, we wanted ..." | Read more » over 8 years ago
donblair "E.g. I just found this: http://wiki.openmusiclabs.com/wiki/PWMDAC And, oh gosh, this is fun: http://sensorium.github.io/Mozzi/ And: http://www.ucho..." | Read more » over 8 years ago
donblair "Good call on the power control chip -- for the riffle-ito design, I'm just using an LDO, which should provide a relatively clean signal? But yeah,..." | Read more » over 8 years ago
mathew "the power issues are going to be tough. Most power control chips do tricky high-speed things to push out a DC signal and the voltage isn't very cle..." | Read more » over 8 years ago
donblair "Egads! Mat, thanks for pointing this out! I totally flubbed that one: in the 555 approach, the signal that is passing through the water is indee..." | Read more » over 8 years ago
mathew "the 555 is pretty simple. There's not that much inside of it. If it simplifies the power circuitry issues you're facing then go with it. I hadn'..." | Read more » over 8 years ago
donblair "Ah -- great thoughts! And your comment points to an important issue, which is that I myself was unclear (and still am, a bit) as to the utility of..." | Read more » over 8 years ago
mathew "This is really cool. I would never want to discourage someone from using a 555. And it would be totally sweet to use audio gear to record and ima..." | Read more » over 8 years ago
EdMallon "Hi everyone, Just a quick note to say the first gen loggers survived their initial 3 month deployment giving us real water flow data, (6m depth,~ ..." | Read more » over 8 years ago
flint "I would be happy to take some advice as to how to best show off the strembot. " | Read more » over 8 years ago
mathew "well, there's no explanation on your website. By googling the name on the sensor name visible in a photo of yours, I can see that its an e-tape mi..." | Read more » over 8 years ago
flint "No, it uses a passive depth sensor strip. See website. " | Read more » over 8 years ago
mathew "I'm wondering if you could post some more details or sketches of your design? is it using conductivity? " | Read more » over 8 years ago
EdMallon "Hi everyone. I just wanted to post an update as I have done some major code development for the Cave Pearl data logger recently, and a weeks wor..." | Read more » over 8 years ago
EdMallon "Hi Warren. Nice to meet you. Wrt cross posting, I am wondering about the content that would be most helpful to the audience here, as I interwove (w..." | Read more » over 8 years ago
warren "Also see this newly posted discussion of dragging underwater loggers: http://publiclab.org/notes/maxliboiron/02-11-2014/underwater-plume-sampling-m..." | Read more » over 8 years ago
warren "Wow, very cool, Ed. Would you be able to cross-post your blog here? How could we make that easier for you? I think a lot of folks here would be int..." | Read more » over 8 years ago
eustatic "Ed, see my note, excited about this effort. http://publiclab.org/notes/eustatic/3-27-2012/thoughts-water-sensing-needs-non-profits-louisiana " | Read more » over 8 years ago