AquaSense

Florida nature preserves rely on infrequent manual water-quality checks. Continuous monitoring is the right tool, but commercial buoys cost thousands per unit. For a high school CAS team that's not a project, it's a barrier.

A four-person CAS team built a buoy from a Raspberry Pi, three sensors (DS18B20 temperature, pH probe, TS-300B turbidity), an ADS1115 ADC, an INIU power bank, and an IP67 case mounted on a PVC float frame. Total bill of materials kept under $150. Logs to a small dashboard over Wi-Fi when in range.

Deployed in a local preserve and operated through a CAS cycle. Proof that real environmental hardware doesn't have to be expensive — only the BOM has to add up.

• Raspberry Pi · $35
• DS18B20 (temp) · $4
• pH probe · $35
• TS-300B (turbidity) · $9
• ADS1115 ADC · $5
• INIU power bank · $25
• IP67 case + PVC float · $30
• Total · <$150

Hand the design off to the next CAS cohort. The interesting durability test is whether the build survives a year of student turnover.