smithtek-nodered-gps

GPS USB extension for the PassPort

Installation Install using the NodeRED palette manager

Usage

The smithtek-nodered-gps node parses NMEA sentences from GPS data received from the PassPort USB GPS module. Every second, it outputs a JSON object containing the following properties:

• Latitude and Longitude (converted to decimal degrees format)
• Date and Time UTC (converted to standard format and Unix epoch)
• Speed
• Heading
• Number of satellites in view
• Altitude

Serial Port Setup

To correctly set up the serial port for communication with the GPS module, use the following settings in a Serial In node:

• USB Port: /dev/ttyACM0
• Baud Rate: 9600
• Data Bits: 8
• Parity: None
• Stop Bit: 1
• Split Input: After a timeout of 500ms
• Data Format: ASCII strings

Note: DTR, RTS, CTS, DSR are not used in this setup. Leave these settings as default.

Units

• Latitude and Longitude (converted to decimal degrees format) - Units: Degrees
• Date and Time UTC (converted to standard format and Unix epoch) - Units: UTC and Epoch Time
• Speed - Units: Knots
• Heading - Units: degrees
• Number of satellites in view
• Altitude - Units: Meters

Epoch Time

The node will convert the GNS time to epoch. This will be stored in the global context "gns time" and can be used within your project.

if (gnstime !== undefined) {
    // "gnstime" is defined in the global context
    node.warn("gnstime: " + gnstime);
} else {
    // "gnstime" is not defined in the global context
    node.warn("gnstime is undefined");
}
return msg;

The GNS time is UTC. The UTC is converted to Epoch unix, there is a offset property in hours that allows you to synchronize your Epoch time output to your local time zone. Use the provided UTC time chart to assist you get the correct offset. Offset is in hours + or -. For example to match the time of Western Australia you would enter 8 that is 8 hours.

License

Copyright (c) 2023 www.smithtek.com.au Licenced under the terms of the GPLv3 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAMIEN CLARK BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

www.smithtek.com.au