Display Formatted GPS Info on OLED

Brad Buskey

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Brad Buskey

Here is a raw example
{
"age": 0,
"latitude": "38.1234",
"longitude": "-80.1234",
"elevation": "123.4",
"course": "",
"speed": "N"
}

Or with the -S
{"age": 0,"latitude": "38.1234","longitude": "-80.1234","elevation": "123.4","course": "","speed": "N"}

Brad Buskey

Update - the script is now working correctly (it was not pulling in the GPS at all, actually)

'#!/bin/sh
oled-exp -c
oled-exp invert on

VAR=$(ubus -S call gps info)

if [ $VAR != '{"signal":false}' ]
then
oled-exp write $VAR
else
oled-exp write "No or Weak GPS Signal"
fi
exit 0

the above script actually writes the GPS info to the OLED. I just dont know how to parse the text to show it in the format I wish. It currently looks like this on the OLED

{"age":174,"latitude"
:"38.3541","longitude
":"-85.5559","elevati
on":"194.7","course":
"","speed":"N"}

Below is how I wish the text to be displayed, but I dont know how to do that. I realize the coding in the OGPS package has the Speed and Course interchanged.

Current Location
Latitude: 12.3456
Longitude: -65.4321
Elevation: 123.4
Course: N
Speed: 12

Lazar Demin

@Brad-Buskey You can modify the $VAR variable before you display it on the OLED.
Try looking up the sed and awk commands for string manipulation

Brad Buskey

I am wondering if I should use Python instead? I was looking into SED and AWK and my head spun. Use the shell script to create a txt file with the information and then the oledExp functions in python to write the lines exactly how I want them. Or, is it possible to pull the "ubus call gps info" from python into a variable and do everything within python? Or is there even a GPS module for python?

This is probably going to only really show my own journey trying to figure out string manipulation.

Brad Buskey

Python may be the answer. I can now run a shell script that writes the GPS data to a file and then runs a python script that reads that file and outputs the data to the OLED. Now, I just have to figure out how to pull different bits of data from the string and get it on the correct lines.

Brad Buskey

OK, new scripts have been created, I can now get the screen set up the way I want. All I have to do now is to read in the file and separate the data into the variables. I'm getting there, but slowly.

{"age":6357,"latitude":"38.1234","longitude":"-80.1234","elevation":"1234.5","course":"12.34","speed":"N"}

needs to be split so that I get back

lat="38.1234"
lon="-80.1234"
elv="1234.5"
cou="12.34"
spd="N"