This is a guide to a filter compatible with the ‘Air Conditioning Water Collector and Reuse System’ (SCRAAC) developed by the FLL robotics team Galilegos from Porto Alegre, Brazil.

Step 1: Materials

For this project you will need:

1. Four PET bottles;

2. Gravel;

3. Activated charcoal (powder or stick);

4. Medium sand;

5. Cotton;

6. Coffee strainer (cloth);

7. Insulating tape;

8. Scissors;

9. Drilling machine.

Step 2: Cut the Bottles

In this part of the project you may cut the bottles 13cm (5,1 inches) from the superior part of the tap.

Step 3: Limit the Sections

Use the drilling machine to open a hole in the superior part of the taps and accomodate the coffee strainer, in a way that covers the hole.

Step 4: Sterilization

In the process of sterilizing the materials, rinse the sand and gravel, remove excess water and bake the materials for 2 hours at 300 Celsius degrees (572°F).

Step 5: Distribution of Materials

Fill the bottles with cotton, activated charcoal, medium sand, and activated charcoal and gravel together in one.

Step 6: Glue the Bottles

To assemble the filter, attach the bottles with insulating tape so that the top of the bottle is centered in relation to the bottom bottle.

Order of the bottles (top to bottom);

- Activated charcoal and gravel;

- Medium sand;

- Activated charcoal;

- Cotton.