st599 / nmea0183-wifi-multiplexer

Reads NMEA0183 messages from two serial lines and forwards multiplexed messages to USB-Serial and WLAN as UDP broadcast.

NMEA0183 WiFi Multiplexer with ESP8266 (D1 Mini)

Caution!

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This is an updated version (0.2) with pins changed from D7/D8 to D6/D7 to avoid boot problems (see Issues). If you ordered already a version 1.0 PCB, then just cut the connection to D8 (e.g. with a knife) and solder a wire to D6 pin on D1 Mini. The updated software (version 0.2) will work then. But with changed serial line numbers from #1 to #2 and vice versa.

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The project reads NMEA0183 messages from two serial (RS232) inputs and forwards multiplexed messages to USB-Serial and WLAN as UDP broadcast.

The multiplexer is powered either from USB connection or with 12 Volt via DC-DC converter. ESP8266 is using Software Serial on ports D6 and D7.

Main purpose is to provide GPS and AIS information wirelessly to a tablet/smartphone for navigation. Works with Navionics app (configure UDP connection with Host: x.y.z.255 and Port: 4444).

There is also a software version that is parsing the messages and can suppress certain messages. This version needs this additional NMEA0183 libray: https://github.com/ttlappalainen/NMEA0183

Just change the settings in the programm according to your needs:

// Change these values only
// ------------------------------------------------------------------------
#define AP 0             // Set to 1 to act as Access Point, 0 as client 

const char *ssid      = "ssid";           // Set WLAN name
const char *password  = "password";      // Set password

const char *udpAddress = "192.168.4.255"; // Set network address for broadcast
const int udpPort = 4444;                 // UDP port

#define BaudRate1 4800   // Baud rate for serial#1
#define BaudRate2 38400  // Baud rate for serial#2

// -------------------------------------------------------------------------

KiCad files are available to change/extend and to create a PCB.

Parts

• U1: ESP8266 (D1Mini)
• U2: Max232
• C1-C4: 4* Capacitor 1µF
• J1-J3: 3* Connector
• U3: DC-DC Converter
• Board @Aisler.net

Updates

• 10.11.2022 - Version 0.3: Corrected line end handling to avaid duplication of messages sent (see Issues).
• 01.10.2021 - Version 0.2: Changed pins from D/D8 to D6/D7 to avoid boot problems (see Issues).
• 06.03.2021 - Version 0.1: Initial version