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sensors [2019/10/08 14:16] – created nikolal | sensors [2022/09/19 11:34] (current) – external edit 127.0.0.1 | ||
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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. Battery power is also possible, | ||
+ | but not used in the Otter project. | ||
+ | |||
+ | ===== Making custom IMC messages ===== | ||
+ | * [[http:// |