About water quality monitoring

Together with Citymine(d), a non-profit focusing on urban development, Bagaar put together a water quality testing unit that will measure the quality of pond water in urban areas, the Pacco-test.

The challenge

Citymine(d) had been working on the Pacco-test project for a while but was struggling to get everything working together. That’s why they asked Bagaar to have a look at it and get it up and running, both software and hardware. We evaluated the task and found two main challenges.

First, this is an open source project, so it was important that everything we built, can be built by people from the community. Therefore, we tried to reduce costs and we constructed the raft using materials that can be bought in a local DIY hardware store.

And as for the technical side of things: battery usage has been a big challenge. The testing unit has to be in the water for as long as possible with as little maintenance as possible. So we set out on a mission to keep energy usage low, eventually reaching -theoretically- 1,5 years of battery life on a single charge.

Our approach

We started by selecting the components that were needed to collect the data. This includes probes, a communication module and the right hardware to tie it all together. The main focus during the search was energy usage and the shielding of the probes.

The probes are connected to a Tentacle Shield which sends the data via a Waspmote and LoRa communication module combination to a server where it is stored. The data is collected every two hours and sent through twice a day.

When the right components had been selected, the construction of the raft kicked off. Main focus during this part of the design was to keep the electronics dry but still accessible for maintenance work using durable, eco-friendly and accessible materials. This posed quite a challenge, as we also didn’t want it to look like floating trash. We ended up using PVC sewer pipe modules as a housing and a cork base to keep it afloat on the pond.

Finally, we also put together a manual that guides the users through the entire process of assembling a Pacco-test.


We tested the entire assembly in our very own Bagaar Aquatics Centre, making sure everything was fully watertight and the probes did their job. Multiple versions of the cork base were tested, and we tried to keep the design simple and elegant while maintaining strength and durability.

Testing in our very own Bagaar Aquatics Center


When the design was close to being finished, we got ourselves a boat and tested the complete assembly on the pond in the Leopoldpark in Brussels. It worked!

The data

The Pacco-test uses 5 parameters to assess water quality: pH level (acidity), dissolved oxygen, ORP (oxidation-reduction potential), conductivity and temperature. The combination of these values offers an insight into the current state of life in the water and how it can develop. The raw data is processed into a graph which is accessible online to anybody who is interested.

The launch

The Pacco-test was launched in the Leopoldpark in Brussels with a large part of the community attending the festivities. Together with Brussels’ Secretary of State Bianca Debaets, the entire Citymine(d) team witnessed how Antoine Pacco, Georges Lieben (Bagaar) and Sofie Van Bruystegem (Citymine(d)) bravely got into a tiny rowing boat and installed the unit in the middle of the pond.


In the long term, the Pacco-test has to become a low-cost solution for monitoring the water quality of ponds and streams. It feeds the awareness that needs to be created about water in the city. By making it accessible to schools and other communities, a network can be created that maps the water quality of large areas. This kind of data can then be used for scientific purposes but also as an alarm whenever a stream or pond is polluted.

Find out more about the Pacco-test and Citymine(d) at Citymined.org


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