Context : We are a group of diverse people participating in the Aquathon 1 in Paris, which is a 7 day hackathon about Ocean and River. Here in Paris, citizens come together to brainstorm, design and build something to improve the canal in 7 days, At the last day, we will also put our final prototype in water to test and collect feedbacks from citizens.

Question : Is the water in front of me drinkable ? Can I swim in it ? Is it suitable of biodiversity ? Water pollution is often invisible, we wanted to make it visible more any citizen.

Solution : We decided to provide a DIY device and that could measure different parameters of water quality (pH, NO2, N03, CO2, Cynobacteria, etc). Each water sample tested is geolocalised so that citizen can contribute to generate a water quality profile of the river. This "lab" is based on colorimetric tests measure by a colorimeter.

Step 1: Box Construction

-Wood planks 35x35 cm

-Wooden batten 2x2x8cm

Glue and screw each elements

Step 2: Water Testing Tank Construction

  • Draw the plan of the tank on inkscape
    • Do not forget to add holes for the supply and drain pipe
  • Laser cut a plexiglas plate according to the plan
  • Glue each part with a water resistant glue

Make sure not to put too much glue otherwise it could spill and impact the transparency of the tank.

Step 3: Conception and Creation of the Measurement and Control Device

  • ESP32-Firebeetle
  • LED hot white
  • Photosensor TSL2561
  • Ecranoled 0,96"
  • Temperature probe DS18b20
  • SD card adaptator
  • Clock RTC DS3231
  • Servo motor sg90
  • boutons
  • electric water pump
  • 9V battery
  • power bank usb

Step 4: Support Design for the Tank

We used foam that we cutted with a hot wire to create a support for the tank. We also anticipated that a magnetic agitator could be put underneath the support to mix the water of the reagent.

Each elements are glue with a glue gun.

Step 5: Construction of a Droplet Device

  • Servo motor
  • Wooden stick
  • 4mm pipe
  • Medical droplet device

This was a tricky part. At first we wanted to use a solenoid or a peristatic pump to control the amount of reagent added for each measurement. For time and money sparing we decided to use a medical droplet device instead.

The problem is that the amount of drops that will fall in the tank is dependant of the volume remaining of the tank of the dispenser.

When the arm (servo motor + stick + pipe) goes down it will make drops of reagent fall into the tank. The amount of drops is controlled by the scroll wheel on the medical device.

Step 6: Functioning System (video Incoming)

Step 1 : Fill the tank with the water you'd like to analyse

Step 2 : Click the button the launch the process

The arm will go down to add the reagent

The magnetic agitator will mix the solution

The photosensor will measure the intensity of the solution

Step 3 : Click the button to empty the tank

Step 7: Poster Design and Presentation

The final step of the Aquathon is the public demonstration. For that we designed a poster to present the idea, conception and process.

What was the challenge ? What is our solution ? How did we get there ?

The concept is well received and people are puzzled by the device (espacially children that are happy to test it). People were concerned about the quality of the river, the water they drink. A lot a false idea were also present in their mind.



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