Huliwai (HD)
The HD version of the huliwai is capable of measuring temperature and pressure for over four months at eight measurements per second. It is self-contained with sensors and data logger integrated in one waterproof package.
Compare to the standard version, the HD version has a larger data memory and higher max. measurement rate, but no light measurement capability. Communication requires a USB-to-serial adapter as it has no infra-red communication interface. The temperature and pressure sensors are other the same.
Specifications
| Variable | Metric | Value | Unit | Condition | Note |
|---|---|---|---|---|---|
| Temperature | Range | [0,40] | °C | - | Non-freezing. |
| Accuracy | +/-0.1 | °C | - | - | |
| Resolution | 16 or 24 | bit | - | Configuration-dependent. | |
| Pressure | Range | [0,30] | Bar | - | Roughly 300 meters. |
| Accuracy | 100 | mBar | - | - | |
| Resolution | 0.5 | mBar | - | - | |
| Sampling Interval | - | {1/8, 1/4, 1/2, 1} | Second | - | User-configurable. |
| Endurance | - | 4 | Month | 2xAA alkaline cells. | Battery-limited. |
| - | 6 | Month | 2xC alkaline cells; 1/8s interval. | Memory-limited. Custom battery pack required. |
Note: Endurance tests were conducted with off-the-shelf alkaline cells (e.g. Energizer EN91 for AA). Lithium primaries such as Energizer L91 typically last ~30% longer.
Interface
The logger has a serial (TTL) interface for configuration and data transfer. A USB-to-serial adapter is used to communicate with the loggers from a computer. This requires opening the housing for access to the logger circuit.
Battery
The logger can be configured with 2x AA or C cells. The logger has battery holder for AA cells by default. To use C cells for the extended endurance, a custom battery pack and an alternative chassis are required.