search

benagricola / tracker

Particle Electron GPS / GSM tracker based on fancy-asset-tracker demo and ULOC tracking example.
GNU General Public License v3.0
30 stars 24 forks source link

Bad checksum #2

Open dokterbob opened 8 years ago

dokterbob commented 8 years ago

After starting the app and moving the device (causing a wakeup), while attaining a GPS fix, I am receiving two bad checksum events:

{"name":"spark/status","data":"online","ttl":"60","published_at":"2016-03-20T14:55:43.357Z","coreid":"3f004c000b51343334363138"}
{"name":"GPS","data":"{ error: \"bad checksum\"}","ttl":"60","published_at":"2016-03-20T14:55:46.925Z","coreid":"3f004c000b51343334363138"}
{"name":"GPS","data":"{ error: \"bad checksum\"}","ttl":"60","published_at":"2016-03-20T14:55:47.460Z","coreid":"3f004c000b51343334363138"}

However, regardless of this, the application seems to function properly:

{"name":"t/l","data":"{\"lat\":41.5858552,\"lon\":1.6477745,\"a\":0,\"q\":3915,\"t\":\"gsm\",\"spd\":0,\"mot\":0,\"s\": 0,\"vcc\":3.951100,\"soc\":84.765625}","ttl":"60","published_at":"2016-03-20T14:57:19.526Z","coreid":"3f004c000b51343334363138"}
{"name":"t/s","data":"sleeping","ttl":"1800","published_at":"2016-03-20T14:58:24.503Z","coreid":"3f004c000b51343334363138"}
dokterbob commented 8 years ago

P.S. Yes, Spain is beautiful this time of year. ;)

benagricola commented 8 years ago

This is published by the Adafruit GPS library (copied from fancy-asset-tracker :D), and happens when it is unable to verify the checksum of an NMEA sentence supplied by the GPS module (I believe).

Can remove the message publish or log to Serial instead but requires modifying the Adafruit library. I'm not averse to this but it may be useful to know when bad checksums are received since this might explain why there's no GPS fix.