The sub-surface automated dual water sampler (SAS) was designed by researchers at NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) and the University of Miami to help scientists study water chemistry on shallow reef habitats. It was also created to minimize some of the financial hurdles in marine research by serving as a low-cost open-source alternative to existing water samplers. Explore the SAS website, use it to guide you in building and using your own water samplers, embrace the maker movement and improve on our design. If you are a teacher, there are free lesson plans to download that include labs and activities related to science, technology, and engineering. Enjoy this site and please use the SAS to learn about and explore our oceans!
Origin of the SAS
Build a SAS
DIY Instructions & Open-Source Design
Use a SAS
Programming and Deploying the SAS
Get Lesson Plans and Presentations
The website will always have the most up-to-date build and operation instructions for the SAS on the related pages. This update section is here as a quick reference
for users to identify when changes have been made to the website or SAS design and user protocol.
April 8, 2020:
The company that makes the peristaltic pumps used in the SAS design updated their pump roller carriage in February 2020 to accomodate 4mm diameter motor shafts, rather than just 3mm motor shafts. This means the
new pumphead will work as is and the 3D printed roller carriage outlined in the SAS design is not neccessary as long as the new pumphead is used. The directions and designs online will remain the same for now as this is a new change. If you have any feedback on the new pump style for use in the SAS design let us know!
Updates to the Arduino IDE and the associated Teensyduino software do not include updates to some of the libraries required for the SAS code. Until the SAS code or the software libraries are updated, the simplest workaround is to download older versions of the software. Currently the
versions tested in-house are the 1.8.10 Arduino IDE and the 1.48 Teensyduino loader. Click here
for guidance on downloading past versions of the Teensyduino software.
Thank you to everyone trying out and applying the SAS design! As the companies that we sourced our hardware and software from refine their products your user feedback is invaluable in helping us keep this website up to date and as useful as possible.
If you have any issues, updates, or success stories to share send us an email and we'll do what we can to help.
October 18, 2019:
After identifying issues with power drain on the SAS and variability in battery life the following changes were made to the SAS design.
(1) Installed larger resistors in the voltage divider used in measuring battery voltage for the SAS.
(2) Switched to name brand batteries to maximize consistent deployment time.
(3) Switched to higher quality MicroSD cards of Class 4 or higher to minimize current draw in sleep mode.
The manufacturer of the SAS pumpheads has had issues with some of its tubing being poorly cured which can allow welding, or sealing shut, of the tubing as it sits in the pumphead.
The manufacturer is now using a different style of silicone tubing that seems to prevent the welding from occurring. An alternative is to use any similarly soft peristaltic silicone tubing
of the same diameter as a replacement tube for the pumpheads.
The code has been updated to shorten the calibration step to 10 seconds from 60 seconds. Refer to the Use A SAS section for the updated protocol.
During long deployments the SAS code had trouble functioning properly. The solution was found with the guidance of the creator of the Teensy Sleep Library. Instructions to edit the Sleep library to allow for deployment alarms set for more than
10 days in the future can be found under the "Install the Sampler Code" directions in the Build A SAS section.
The ACCRETE lab has invested in injection molds for production of the SAS endcaps and motor mounts. If you're interested in ordering a production run of these parts for building your own SAS please contact the lab by emailing firstname.lastname@example.org.
Shipping SAS around the world as luggage and mailing boxes of SAS to collaborators has led to more lessons learned, so the team has added a small section with packing recommendations in the Use A SAS section.