New version with added features of the great plugin W-Geronius/signalk-hwt901b-imu (https://github.com/W-Geronius/signalk-hwt901b-imu)
Original documentation (will be update)
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SignalK node server plugin (BETA) reading roll, pitch and magnetic heading from WITMOTION's HWT910B sensor
INPUT:
as of device data sheet and own testing, cable plug respresenting the boat's stern:
0x55 0x53 PitchL PitchH RollL RollH YawL YawH VL VH SUM
CALCULATION：
- Pitch (x axis):
((PitchH<<8)|PitchL)/32768*180(°) - Roll (y axis):
((RollH<<8)|RollL)/32768*180(°) - Yaw (z axis):
((YawH<<8)|YawL)/32768*180(°) - Version：
(VH<<8)|VL - Checksum：
SUM=0x55+0x53+RollH+RollL+PitchH+PitchL+YawH+YawL+VH+VL (least significant byte must match SUM) - Magnetic Heading:
z axis value (yaw) plus an offset determined after calibration and install
PROCESSING:
- Gyroscope has to be calibrated by wit motion windows software prior to final placement onboard
- acceleration calibration, as well as levelling pitch & roll can be accomplished via the plugin's settings:
OUTPUT TO SIGNALK (in rad):
{"updates":[{"$source":"WIT.n",
"values":
[{"path": "navigation.headingMagnetic",
"value":123.456},
{"path": "navigation.attitude",
"value":{"roll":0.123456,
"pitch":-0.123456,
"yaw":null}}
]
}]
}