As explained [in @donblair's primer](/notes/donblair/08-25-2015/turbidity-001), measuring turbidity means "measuring the amount of suspended solids in water -- solids that haven't fully dissolved". That is, "turbidity, an optical technique for assessing suspended solids in liquid -- is an important water quality parameter. Typically, light is shone into a liquid sample, and the amount of light scattered back out of the sample (off of particles suspended in it) is measured; the intensity of this scattered light is considered to be related to the amount of suspended solids in the sample." ([reference](/wiki/turbidity_sensing)) _image credit: https://castlebrookestreamstudy.weebly.com/_ This page needs help! * Info about regulations * Info about ecological or human health impacts * Advocacy leverage points * Constraints we're working within: cost, complexity, sensitivity, time There are a LOT of resources available on these pages by @donblair and others: * https://publiclab.org/notes/donblair/08-25-2015/turbidity-001 * https://publiclab.org/wiki/turbidity_sensing **** ## Questions [questions:turbidity] **** ## Sensors Here's a list of different turbidity sensors and measurement systems. See below for some Do-It-Yourself approaches to measuring turbidity, and [this page](https://publiclab.org/wiki/turbidity_sensing) for more information on how turbidity sensors works. * Kelley et al., An Affordable Open Source Turbidimeter http://www.mdpi.com/1424-8220/14/4/7142/pdf * Hackteria.org, Turbiduino: http://hackteria.org/wiki/DIY_turbidity_meters * Lambrou et al., A Nephelometric Turbidity System for Monitoring Residential Drinking Water Quality: http://www2.ucy.ac.cy/~faniseng/publications/SENSAPPEAL09.pdf - Fondriest review: http://www.fondriest.com/environmental-measurements/equipment/measuring-water-quality/turbidity-sensors-meters-and-methods/ - Hach overview: http://www.hach.com/asset-get.download-en.jsa?code=61798 (see [Water sensors](https://publiclab.org/wiki/water-sensors) for more, and [click here to add to this table](https://docs.google.com/spreadsheets/d/1UwjRqU8kHTwEcnDdO2Zxkr8zkFkaGfyePJ-cdnxJzw0/edit#gid=28737041)) **** ## Activities Activities for people to test methods (these develop over time) [activities:turbidity] **** ## Existing work [notes:turbidity] ...
| Author | Comment | Last activity | Moderation | ||
|---|---|---|---|---|---|
| ggallant | "I have decided to suspend my current turbidity sensor and instead adapt yours to my base station. If it is of interest I have modeled the mechanica..." | Read more » | over 8 years ago | |||
| bhickman | "Hi ggallant. Sounds interesting. I'm trying to picture your design, but I'm not sure if I have it right. Can you post a picture? I definitely thin..." | Read more » | over 8 years ago | |||
| ggallant | "My current led and sensor boards are 6 sided and designed to attach to hardware store 3/4 plugs with plenty of epoxy and silicone sealant. Next rev..." | Read more » | over 8 years ago | |||
| bhickman | "Hi ggallant. I'm using Texas Instrument's Tiva microcontroller which has a couple pins that allow you to tap into the bus power (5V at 1A). For sho..." | Read more » | over 8 years ago | |||
| ggallant | "The LED is specified at 100ma. This "should" need a driver transistor. Outputs pins from the CPU are typically rated at 25ma max. " | Read more » | over 8 years ago | |||
| bhickman | "Hi gretchengehrke, thanks. To answer you questions: (1) I'm using this LED and this photodarling as the detector. The LED has a maximum output at 8..." | Read more » | over 8 years ago | |||
| gretchengehrke | "Hi @bhickman, this is great. Other folks (mostly @donblair) have been working on developing a turbidity sensor too. I have a couple of questions wi..." | Read more » | over 8 years ago | |||
| bhickman | "Hi ggallant. To answer your questions: 1. Yes, the unit is intended for submerged operation. So far I have only had it submerged in beakers in the ..." | Read more » | over 8 years ago | |||
| ggallant | "Couple of questions: 1. Is the unit intended for submerged operation? 2. Extended deployment? 3. How is the water cycled to the chamber? 4. What ar..." | Read more » | over 8 years ago | |||
| pdhixenbaugh | "Re: square wave, I feel really out of my comfort zone here, but that's ok :). I know to make a square wave voltage source, you have to add up sine ..." | Read more » | over 8 years ago | |||
| pdhixenbaugh | "I'll do what I can :D it might be good weekend reading. So take everything that follows from the perspective of me not knowing much about measuring..." | Read more » | over 8 years ago | |||
| donblair | "I need a little help understanding this background. When you modulate the LED at 1 kHz, that means it's flashing on and off 1000 times a second? E..." | Read more » | over 8 years ago | |||
| donblair | "@pdhixenbaugh -- These are great ideas / questions / suggestions! I just posted a quick follow-up here: https://publiclab.org/notes/donblair/03-2..." | Read more » | over 8 years ago | |||
| pdhixenbaugh | "I need a little help understanding this background. When you modulate the LED at 1 kHz, that means it's flashing on and off 1000 times a second? Ho..." | Read more » | over 8 years ago | |||
| liz | "Wow this is so well-written! Thanks for making these concepts accessible. " | Read more » | over 8 years ago | |||
| jpkearns | "Our systems are simpler, lower in cost, and made from common local materials. Please get in touch if you have questions - www.aqsolutions.org " | Read more » | almost 9 years ago | |||
| eustatic | "very cool. good question regaring the water pressure control, I've often wondered that myself. " | Read more » | almost 9 years ago | |||
| liz | "FYI Public Lab, additional informal conversation on this is also happening on the WeChat app -- let us know if you want to join there " | Read more » | almost 9 years ago | |||
| donblair | "Yes, nice! In the picture, it looks like one could place a little cuvette right there in the middle and assess the turbidity :) " | Read more » | about 9 years ago | |||
| warren | "At the Somerville coworking yesterday it occurred to me how similar this is to the optical particulate monitor designs! http://publiclab.org/notes..." | Read more » | about 9 years ago | |||
| cfastie | "This looks very promising. There are a couple of controls that might add a lot to the interpretability of your tests. 1) With the water bottle in ..." | Read more » | about 9 years ago | |||
| mathew | "real clever thinking! " | Read more » | about 9 years ago | |||
| gretchengehrke | "Please post pictures in the comment section that are good example photos. I intend to put this information into a wiki page soon, and would love t..." | Read more » | about 9 years ago | |||
| cfastie | "Neil, Yes, the window slime will probably have to be removed every couple of weeks. Or maybe window transparency could be monitored with a separat..." | Read more » | about 9 years ago |