John McDermott

This LoPy project uses a GPS receiver and sends the location data from LoPy device #1 to LoPy device#2, then posts to the internet using MQTT protocol. Owntracks is used as a mqtt client to map the GPS points.

GPS RX --> LoPy1 > - - - > LoPy2 (mqtt-wifi) > - - > R Pi (mqtt broker) > - - > Owntracks Android mqtt map

For the GPS I use a ublox module NEO 6M on a carrier pcb: GY-GPS6MV2 pin out: VCC <-> LoPy expansion board pin VCC RX <-> LoPy expansion board pin G24 TX <-> LoPy expansion board pin G11 GND <-> LoPy expansion board pin GND

Files in project:

boot.py # unmodified pycom boot file

main.py # set's up wifi and connects to local network if available # updates real time clock from ntp. Not strictly necessary and may be omitted # calls the module to handle GPS and Lora. # use one of the following lines, leave the other as comment, flash one version of each main.py into each LoPy device. # either: # execfile('/flash/LoRaGPS.py') # run GPS and Lora loop to transmit, use this command for sending GPS unit # execfile('/flash/LoRaGPSpost.py') # run Lora loop to receive and post to mqtt

homewifi/homewifi.py # connect to local wifi if available. homewifi/ntp_time.py # update real time clock using ntp. Not strictly necessary and may be left out if desired. homewifi/wifi_name.txt # file containing SSID and password for connecting to wifi. This file must be created and saved to flash. This method done to avoid putting SSID/password in source code files.

gps.py # module to convert data from GPS receiver into object containing required data. Thanks to Peter Affolter for this code.

LoRaGPS.py # module used by LoPy that has GPS receiver and will transmit data to home base LoPy LoRaGPSpost.py # module used by home base LoPy to receive LoRa data containing GPS information, then post using mqtt to broker server.

This example assumes a mqtt server hosted locally, (for example Raspberry Pi with mosquitto installed - there are plenty of tutorials for installing and testing, note if you have wheezy or jessie verions of Raspian)

I have also used the Owntracks app for mapping the data, and connected using the private mqtt setting. refer to: http://owntracks.org/ http://owntracks.org/booklet/ http://owntracks.org/booklet/guide/mqtt/

When testing the setup it is useful to compare the console output from each LoPy, and also on the Raspberry Pi to view using the command: mosquitto_sub -v -t '#' This checks that GPS data is being generated, the second LoPy is receiving, and that the mqtt broker is getting messages.