This work will be presented at MTS Great Lakes in 2025. If curious, I can send you the paper in prep, or check out my website's page for some pictures.
- Traditional CTD: Salinity, temperature, depth sensors with three variants: 1.5in and 2.0in PVC (~140m) or 2.0in steel pipe (~350m)
- Temperature logger: Temperature only monitoring for a ~few days to ~two weeks, based on system configuration
- Bottom Pressure Recorder: Pressure only for tide measuring, research ongoing for three used in conjuction for wave height and direction
- Surface Float: All sensors optional. Salinity, water temperature, GNSS/location, LED beacon, atmospheric pressure/temperature, light, etc.
| Name | Adafruit Part # | What it does | Accuracy | Cost |
|---|---|---|---|---|
| Adafruit Feather RP2040 Adalogger w/ microSD Card | 5980 | Datalogger | — | $15 |
| SD/MicroSD Memory Card (512 MB) | 5252 | Data storage | — | $5 |
| DS3231 Precision RTC FeatherWing | 3028 | Real time clock | ±2 minutes per year | $14 |
| CR1220 12mm Diameter 3 V Lithium Coin Cell Battery | 380 | Battery for RTC | — | $1 |
| Lithium Ion Battery Pack 3.7 V 2.2 Ah (or 2.5–10 Ah) | 1781 (2.2 Ah) | Battery | — | $10 |
| Display | ||||
| Adafruit FeatherWing 128×64 OLED Display (optional) | 4650 | Screen, buttons | — | $15 |
| Location | ||||
| Mini GPS (PA1010D) | 4415 | GPS/GNSS, Time | Testing 10 Hz | $30 |
| Ultimate GPS Breakout (PA1616D) | 5440 | GPS/GNSS, Time | Testing, 10 Hz | $30 |
| External Active GPS Antenna | 960 | For Ultimate | Testing | $21.5 |
| High-strength 'rare earth' magnet | 9 | Hold antenna | — | $2.5 |
| Sensor Cables | ||||
| STEMMA QT / Qwiic JST SH 4-pin Cable | 5385 | Sensor connection | — | $1–1.5 |
| STEMMA QT / Qwiic 5 Port Hub | 5625 | Sensor connection | — | $2.5 |
| Type | Part # | Variable | Depth Rating (m) | Response Time | Accuracy | Cost |
|---|---|---|---|---|---|---|
| Atlas Scientific Mini Conductivity K 1.0 Kit | — | Conductivity | 353 | 90% in 1 s | 99% in 1 s | $200 |
| Waterproof 1-Wire DS18B20 | 381 | Temperature | Not specified | 60% in 12 s, 90% in 31 s | ±0.5 °C | $15 |
| DS18B20 Extender | 5971 | DS18B20 accessory board | — | — | — | $— |
| 10K Precision Epoxy Thermistor | 372 | Temperature | Not specified | 60% in 3 s, 90% in 7 s | ±0.1 – 0.5 °C | $4 |
| Platinum RTD Sensor – PT100 | 3290 | Temperature | Not specified | — | — | $— |
| PT100 RTD Amplifier – MAX31865 | 3328 | Amplifier for PT100 | — | — | — | $— |
| Atlas Scientific K 1.0 Kit | — | Conductivity | 353 | 90% in 1 s | 90% in 1 s | $200 |
| Blue Robotics Celsius Fast-Response (TSYS01) | — | Temperature | 975 | 3 s (90% in 2 s, measured) | ±0.1 °C | $70 |
| Blue Robotics Bar02 / Bar30 / Bar100 (pressure options) | — | Pressure | 10m, 300, 1,000m | — | — | $80, $90, $380 |
Note: Response time and accuracy are from manufacturer specs and initial testing. For reduced costs, static deployments may not need a pressure sensor.
Depth rating for temperature sensors not from Blue Robotics are not specified by manufacturers and depends on sealant/epoxy.