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| sensors [2019/10/08 14:16] – created nikolal | sensors [2025/01/28 13:14] (current) – [Sensors] nikolal | ||
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| ====== Sensors ====== | ====== Sensors ====== | ||
| - | To receive information from the fish tags, the Otter is equipped with an Thelma Biotel | + | The hydrophone used on the Otter is a [[https:// |
| + | tag, as well as measurements taken in the hydrophone. | ||
| + | Depending on the software version ordered from the manufacturer, | ||
| + | on 63-77 kHz. Typically, lower frequencies are only suitable for larger tags, while higher frequencies are mostly | ||
| + | used in smaller tags. It detects tags that transmit using using Differential Pulse Position Modulation (DPPM), and | ||
| + | can use different protocols to give meaning to the time delays between pulses. | ||
| + | |||
| + | The communication with the controlling computer is through a RS-485 interface, delivering messages in | ||
| + | a NMEA 0183 inspired format. Bluetooth communication is also present, but | ||
| + | not used for real-time operations like those the Otter target. Instead, it can be used to download lists of | ||
| + | detections after a mission has been performed. | ||
| + | |||
| + | Power is supplied through the same cable as the RS-485 uses, but in a separate lead. It accepts a DC voltage of 5-12V, so 5V is used in the Otter because it was available and unused by the other components. | ||
| + | ===== Making custom IMC messages ===== | ||
| + | * [[http:// | ||