Hi Folks,

Today I’m going to show you how to create a Sigfox GPS tracker using Wia and the Pycom SiPy.

This tutorial assumes that you have already connected Sigfox to Wia if you haven’t, please click here to find a tutorial for initial Sigfox setup and publishing data to Wia.

Components

• Pycom SiPy
• Pytrack Expansion Board
• Sigfox compatible antenna
• Mobile device (iOS or Android)
• Wia Platform

Setup your board

• Connect the SiPy to the Pytrack board. (The RGB LED on the SiPy should be on the side of the usb port on the Pytrack board)
• Connect the Sigfox antenna to the SiPy. (The connection is just left of RGB LED)

Setup Your Project

• Create a new folder for your project. I'm going to call mine pycom-pytrack
• In Atom, go to File > New Window to open a new window
• Add your newly created folder by clicking File > Add Project Folder and navigating to it
• If the Pymakr plugin is not open at the bottom of your Atom window, click on the arrow on the right hand side to open it
• Select Settings > Project Settings. In the address field replace the value with the device name from the step above e.g. /dev/tty.usbmodemPy343431 (Mac OS X), COM3 (Windows), /dev/ttyACM0 (Linux) then save the file

Add required libraries

• Right click on the folder name in Atom and click Add Folder. Enter lib as the folder name
• Right click on the lib folder and click New File. Enter urequests.py as the file name
• Click on the file then copy and paste the code from here into that file then save it.
• For Pytrack, additional libraries must also be added to the lib folder, these can be found here

Publish A Location Event

• We'll need two files for our application:
  • boot.py which is run when the device is powered up
  • main.py which is where our main code is
• In Atom, right click on your project and click New File. Enter boot.py as the filename
• Copy and paste the code below into the file

from machine import UART
from network 
import Sigfox 
import binascii 
import machine 
import os
# initalise Sigfox for RCZ1 (Europe) (You may need a different RCZ Region) 
sigfox = Sigfox(mode=Sigfox.SIGFOX, rcz=Sigfox.RCZ1)  

# print Sigfox Device ID 
print("ID: ", binascii.hexlify(sigfox.id()))  

# print Sigfox PAC number 
print("PAC: ", binascii.hexlify(sigfox.pac()))  

uart = UART(0, baudrate=115200) 
os.dupterm(uart)  

machine.main('main.py')

• Right click on your project and click New File. Enter main.py as the filename
• Copy and paste the code below into the file

from network import Sigfox 
from pytrack import Pytrack 
import urequests as requests 
from L76GNSS 
import L76GNSS 
import socket 
import time import pycom 
import struct  

py = Pytrack() 
gps = L76GNSS(py, timeout=60)  

init_timer = time.time()  

print("connecting to Sigfox") 
# init Sigfox for RCZ1 (Europe) 
sigfox = Sigfox(mode=Sigfox.SIGFOX, rcz=Sigfox.RCZ1)  

# create a Sigfox socket 
s = socket.socket(socket.AF_SIGFOX, socket.SOCK_RAW) 
# make the socket blocking 
s.setblocking(True) 
 
s.setsockopt(socket.SOL_SIGFOX, socket.SO_RX, False)  

# Post an location to the Wia cloud via Sigfox backend 
def post_location(latitude, longitude):
 try:
   print(str(latitude), ":", str(longitude))
   s.send(struct.pack('f',float(latitude)) + struct.pack('f',float(longitude)))
 except:
   pass  
# main loop 
while True:
 final_timer = time.time()
 diff = final_timer - init_timer
 # Get coordinates from pytrack
 coord = gps.coordinates()

 # If the GPS has coordinates and 15 minites has past. Post the location data
 if not coord == (None, None) and diff < 900:
 lat, lng = coord
 post_location(lat, lng)
 init_timer = time.time()

• L76GNSS.py

• LIS2HH12.py

• pytrack.py

• boot.py

• main.py

Parsing the Data

• Drag the trigger event node from the left hand side onto the canvas
• Click on the node and enter sigfoxDataUplink as the event name
• Enable your Sigfox Device as the event source
• Now add a function node from the logic section (We’ll parse the data here)
• Add a location node from the output section

Click on the function node and add the following code:

• Each of GPS coordinates is 32 bits or 4 bytes of data

• They are 2 characters that can fit into 1 byte of data, hence why we split our hexadecimal string by 8

Send a Push Notification

• Drag over a location node from the trigger section now. With this we can capture the node created from the previous Flow chain
• Add the same Device as earlier to the location trigger node
• Drag over a notification node and enter the following text

Now you should receive Sigfox data to your mobile device.