Project lead: Mitch Nelke


The OPEnSampler is an openly published water sampler capable of sampling from various sources into either mylar bags or hard plastic bottles. Printed circuit boards interface with an Arduino Uno microcontroller to control an array of 24 solenoid valves, allowing the sampling containers to be sealed from the environment when they are done filling. The frame is assembled with Misumi's 15mm aluminum extrusion, cut to length by the manufacturer. The universal mounting system of aluminum extrusion allows users to add their own modifications to the sampler, such as sensors or additional mechanical components. 3D printing is used extensively to create new bag caps that interface with both the aluminum extrusion and silicone or teflon tubing, as well as for electronics mounts and containers. The entire device fits in Pelican's 80QT Wheeled Cooler which retains ice for up to 10 days. 


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  • 24+ individually addressable sample containers
  • Configurable sampling intervals and timing
  • Capable of 60+cm/s flow velocity
  • Openly published, modular design and PCB
  • Customizable dimensions and components
  • GSM communications enabled
  • Follows the EPA's qualities of an ideal sampling device discussed in multiple studies [1] [2] [3], including but not limited to sample velocity, configurable sample intervals, number of sample containers, and device portability and adaptability.


We have recently shipped the first OPEnSampler to Zurich, Switzerland, where it will be field tested and compared to other samplers already in use. We are currently building two newer versions of the OPEnSampler: the bagged sampler shown in the CAD, and a larger bottled sampler. 


The goal of this project is to have it grow on its own; we want you to help develop it. By publishing the design, code, and instructions, we will enable others to add their own modifications to fit their applications with minimal effort. We will serve as the hub of activity, sharing new developments publicly so that a database of ways to use the OPEnSampler and how to modify it to fit specific needs can be viewed by anyone working on similar projects around the world.


OPEnSampler. Water Sampler. 3D Printing. Customizable Instrument. Arduino.



The studies linked below, conducted by the EPA in the 70's and 80's, form the basis of the decisions behind qualities of many commercial samplers. We also based many of our design criteria on the discussion of ideal water sampler characteristics. The EPA's studies are also great references for how to collect and store samples in the field to achieve the best results.

[1] United States Environmental Protection Agency, (1982). Handbook for Sampling and Sample Preservation of Water and Wastewater. Cincinnati, OH, EPA. [Accessed Nov 20, 2017].

[2] Harris and Keffer, United States Environmental Protection Agency, (1974). Wastewater Sampling Methodologies and Flow Measurement Techniques [Accessed Nov 20, 2017].

[3] United States Environmental Protection Agency, (1977). Sampling of Water and Wastewater. Cincinnati, OH, EPA. [Accessed Nov 20, 2017].



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