Public Lab Research note

EcoSen -> How healthy are our water resources? (In construction)

by alejobonifacio | May 17, 2020 20:17 17 May 20:17 | #23659 | #23659


We need healthy water resources!

Clean freshwater around the world is scarce and it is becoming more scarce. But we can do something.

We can measure water quality to claim to the government or to the people who is polluting it, so we are going to :

  • learn how to measure water quality
  • build a data logger for environmental quality
  • share our work to raise awareness about caring for clean water

EcoSen - LoRa Data-Loggers for environmental quality (Español abajo)

Environmental monitoring is essential due to the variety of ways in which it is threatened. Usually recording environmental variables can be carried out by private data loggers. These devices, due to their high costs, or being of closed design, do not allow us to buy in quantity or build them. Our proposal consists in the design and development of open hardware data loggers with LoRaWan technology for communication with devices for downloading data. The data loggers will be of two types: aquatic and terrestrial. Aquatics will measure relevant data for the determination of water quality such as turbidity, dissolved oxygen, conductivity and pH. The terrestrial, will measure bee activity variables in hive, biological indicators of environmental quality. These data loggers are based mainly in the Cave Pearl Proyect, but with adaptations to surface waters.


We want to bring to society the passion for monitoring rivers and lakes. Also with the plus of learning about open electronic projects with possibility of reproduce, modify and customize data loggers. The Open technology that we bring is associated with open data repositories that will make the environmental information accessible to everyone!

The first steps, measuring

To begin recording environmental variables is necessary to develop some abilities measuring these. To do that we are gonna start making a Coqui conductivity sensor of Public Lab website. With this task, we are learning to measure environmental variables with an open source hardware

Second step, logging

To begin logging we are going to made an Arduino Uno based data logger. This data logger is based in one of the [Cave Pearl Projects] ( After complete the datalogger we are going to add a DHT11 temperature and relative humidity module to pin 8 of Arduino Uno. The code.ino is downloadable in the following linkor in the Codes folder.


Materials needed

Specifications & Technical Attributes

The specific attributes of the data logger you build will depend slightly on the type of sensors you buy for the system. The numbers shown below are for the full version of the data logger that contains exactly the parts that we suggest in our build documents and parts list. Below, you can see which parts could be changed for which spec upgrades.

Attribute Value [SI]
Weight 1 [kg]
Footprint 30x5 [cm]
Battery Capacity 6800 [mAh]
Operating time 3months
Approximate Max wireless communication 3 [km]
Communication (in this guide) Arduino IDE (windows, mac, GNU/linux)
Cost ~ U$S350
Table of compenents

Quantity Value U$S Link
arduino pro mini 1 3.881656805 ->
Arduino mega 1 9.349112426
temperature sensor ds18b20 1 4.130177515
sensor de turbidez 1 15.66863905
pH sensor 1 29.5
conductivity sensor 1 79.9
disolved oxygen sensor 1 169
real time clock 1 2.970414201
18650 battery charger 1 2.911242604
battery holder 1 1.124260355
rechargable 18650 batteries 2 3.360946746
LoRa module 2 15
Hermetic case 2 8,272189349
Electronic stuff(jumper wires, terminal boards, soldering tin, etc.)


This data logger is designed to function similarly to the Cave Pearl Proyect data logger designs:

  • Autonomous: this data logger has an autonomy of several months
  • Customisable: Allows to choose what sensor you want for your data logger
  • Wireless communication: Thanks to the LoRa connectivity this device can send a measurements to a server and get access to the information wherever you are. This feature is new to the Cave Pearl Proyect data logger.

We chose a Arduino pro-mini to be the "brain" of this data logger for its versatility, accessibility, simplicity, and ability to add and upgrade your own modifications. Any method with which you can communicate with a arduino pro-mini (bluetooth, WiFi, LoRa, etc) can be added to the data logger to get the information from its.

List of components


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Hi @alejobonifacio , glad to see this project getting started! What are you thinking about doing next?

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Hello Liz! the project is about data logging and sharing water quality with open hardware. If you want to hear more about the project, I invite you to see the presentation this Thursday at 16 UTC And you can follow the project on twitter Sincerely Alejo

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Thank you @alejobonifacio ! I aim to tune in.

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I did this! Hi! Long time has passed since this original post. I was doing some in field measurements with this Cave Pearl Project based data logger. I have to give thanks to @edmallon and Patricia Beddows for the terrific job with the Cave Pearl Project. For this instance I just measure temperature. This is only one variable related to water quality. I choose to begin with this because it is the most inexpensive sensor. I put the data logger in a plastic case for measurements of water temperature in four different sites. This case has to be outside water because it is not waterproof. My next step will be the submerged case. I took advantage of a work trip in which I went to sample fish, invertebrates and birds with the research team that I work for to assess water quality. In this kind of trips, we use privative probes and data loggers for field measurements and I want to change it to Open Science Hardware alternatives.

Let’s see what I got in the field.


This is a graphical shows the different temperatures between 4 sampling sites of Suquía basin, Córdoba, Argentina and a measurement in the laboratory

These table shows the average Timestamp for each site


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