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WEGMATT
LLC
Contents
1
Disclaimer ..................................................................................................................................3
2
Introduction ...............................................................................................................................3
3
Pinout ........................................................................................................................................4
3.2
Power ............................................................................................................................................ 5
3.3
Serial 1 ........................................................................................................................................... 5
3.4
Serial 2 ........................................................................................................................................... 6
3.5
I2C ................................................................................................................................................. 6
3.6
GPIO .............................................................................................................................................. 6
3.7
Antenna connector ....................................................................................................................... 6
4
Interfaces ...................................................................................................................................8
4.1
I2C ................................................................................................................................................. 8
4.1.1
Read/Write Operation .......................................................................................................... 8
4.1.2
Device Address ...................................................................................................................... 8
4.1.3
Register Layout ..................................................................................................................... 8
4.1.4
NMEA message stream ......................................................................................................... 8
4.2
GPIO .............................................................................................................................................. 9
4.2.1
Overview ............................................................................................................................... 9
4.2.2
None ...................................................................................................................................... 9
4.2.3
Reset ..................................................................................................................................... 9
4.2.4
Sleep ...................................................................................................................................... 9
4.2.5
LNA ........................................................................................................................................ 9
4.2.6
AIS message ........................................................................................................................ 10
4.2.7
I2C data ............................................................................................................................... 10
5
Using the dAISy FeatherWing .................................................................................................... 11
5.1
Interpreting the status LEDs ....................................................................................................... 11
5.2
Configuration and debug menu .................................................................................................. 12
6
Tips for good AIS reception ....................................................................................................... 14
6.1
Antenna ....................................................................................................................................... 14
6.2
Location, location, location ......................................................................................................... 14
1
dAISy FeatherWing AIS Receiver
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Table of Contents
Related Manuals for Wegmatt dAISy FeatherWing
Summary of Contents for Wegmatt dAISy FeatherWing
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Page 1: Table Of Contents
LNA ............................9 4.2.6 AIS message ........................10 4.2.7 I2C data ..........................10 Using the dAISy FeatherWing ....................11 Interpreting the status LEDs ....................... 11 Configuration and debug menu ....................12 Tips for good AIS reception ....................... 14 Antenna ............................14... - Page 2 Radio frequency noise ........................ 15 Troubleshooting ........................15 Specifications ........................... 16 Source code and schematics...................... 17 Contact ..........................17...
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Page 3: Disclaimer
. The dAISy FeatherWing allows you to receive these transmissions, enabling real-time tracking of nearby vessels. The dAISy FeatherWing outputs the AIS data as a stream of ASCII messages, which are encoded in a marine standard format known as AIVDM sentences . -
Page 4: Pinout
3 Pinout The pinout of the dAISy FeatherWing is compatible with the Adafruit Feather Specification Figure 1: Bottom view of dAISy FeatherWing The table below lists all pins and their function. All other pins are not connected to any part of the circuit. -
Page 5: Power
3.2 Power Power for the dAISy FeatherWing is supplied through the 3V3 and GND pins. The pins align with 3.3V and GND pins of the Adafruit Feather. dAISy Feather 3.3V Table 2: Power pinout The dAISy FeatherWing is a 3.3V device. Applying a voltage higher than 3.3V will damage the dAISy FeatherWing! In regular operation the dAISy FeatherWing draws 70 mA of current, equivalent to 230 mW of power. -
Page 6: Serial 2
By default, no function is enabled, and the IO pins are disconnected. See chapter 0 for a detailed description of the configurable GPIO functionality. 3.7 Antenna connector The edge-mount antenna connector of the dAISy FeatherWing is a female SMA connector with standard polarity. - Page 7 The dAISy FeatherWing is matched for an antenna with an impedance of 50 ohms, which is standard for marine VHF communication.
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Page 8: Interfaces
4.1 I2C 4.1.1 Read/Write Operation The dAISy FeatherWing supports the I2C protocol with 7-bit device address, followed by the R/W bit. For a write operation, the first byte sent is the register address byte. The next byte sent is written to that address. -
Page 9: Gpio
4.2 GPIO 4.2.1 Overview The functionality of pins IO1 and IO2 of the dAISy FeatherWing is configurable. The following functions are available: Function Electrical High None (default) Not connected Reset Input, pull-down Pulse high for > 100 ms to trigger reset... -
Page 10: Ais Message
4.2.6 AIS message With this function enabled, the selected IO pin will output a positive pulse when a valid AIS message is received. Typical applications include waking up the Feather when new AIS messages arrive, or driving an LED indicating when valid AIS messages are received. The length of the pulse depends on the size of the AIS message and typically ranges from 400 to 1200 us. -
Page 11: Using The Daisy Featherwing
5 Using the dAISy FeatherWing Using the dAISy FeatherWing is as simple as connecting it with an antenna and a PC and powering up your AIS capable application of choice. When powered on, the dAISy FeatherWing automatically starts to listen for AIS transmissions. -
Page 12: Configuration And Debug Menu
The LEDs are turned off while the dAISy FeatherWing is in sleep mode. Ensure that the IO pin configured for sleep control is either driven low or not connected. Reconfigure the IO pins if sleep mode is not required. The LEDs are also turned off while the dAISy FeatherWing is in the configuration menu. Connect to dAISy with a serial terminal and press ESC. - Page 13 C: Configure the radios of the dAISy FeatherWing to listen to specific AIS channels. The dAISy FeatherWing has two radios, which by default are configured to listen on channel A at 161.975 MHz and channel B at 162.025 MHz respectively. The dAISy FeatherWing also support the less common “Long range AIS”...
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Page 14: Tips For Good Ais Reception
VHF antenna installations. IMPORTANT: Do NOT directly connect the dAISy FeatherWing to the same antenna as your VHF radio. This will damage the AIS receiver! To share an existing antenna with a VHF radio, use an ACTIVE splitter. -
Page 15: Radio Frequency Noise
Outdoors is better than indoors (computers, power-supplies, wireless networks, LED lights ...). Countryside is better than down-town (taxi radios). The dAISy FeatherWing has an integrated bandpass filter to reduce the impact of radio frequency noise outside the marine VHF band frequency. -
Page 16: Specifications
8 Specifications Power Input voltage 3.3 V Input current with LNA enabled (default) 70 mA Input current with LNA disabled 35 mA Input current in sleep mode 0.35 mA Radio Independent receivers Frequency bands 161.975MHz, 162.025MHz, 156.775MHz, 156.825MHz AIS channels 2, freely configurable Sensitivity with LNA enabled (default) -113 dBm @ 20% PER... -
Page 17: Source Code And Schematics
Currently the dAISy FeatherWing is only partially open source. The core of the dAISy FeatherWing, how the Silicon Labs Si4362 radio IC is programmed to receive AIS, is available on Github. While that project does not include all the functionality of the dAISy FeatherWing as sold, we do backport any bug fixes that are relevant to the task of receiving AIS.
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