Lopy with pytrack, how connect/use GPS?

[zceld]

@zceld
Well finally it seems that with this code at least try to get the GPS coordinates.

On the other hand now comes another problem and it seems that it runs out of memory. What do you think? the idea of operation is to collect the signal from the gps of a vehicle and send it to LoRa. I understand that if it is due to lack of memory, it will be necessary to program something to clean the cache or something that increases when using the program, not?

CODE:
import time
from L76GNSS import L76GNSS
from pytrack import Pytrack

py = Pytrack()
l76 = L76GNSS(py, timeout=30)
while (True):
coord = l76.coordinates()
print(coord)
time.sleep(1)

I am waiting for new news. Thank you very much for your patience

[zceld]

@zceld

I am happy to inform you that with this code I have at least managed to obtain coordinates without failure:

Code:

import machine
import math
import network
import os
import time
import utime
from machine import RTC
from machine import SD
from machine import Timer
from L76GNSS import L76GNSS
from pytrack import Pytrack
# setup as a station

import gc

time.sleep(2)
gc.enable()

# setup rtc
rtc = machine.RTC()
rtc.ntp_sync("pool.ntp.org")
utime.sleep_ms(750)
print('\nRTC Set from NTP to UTC:', rtc.now())
utime.timezone(7200)
print('Adjusted from UTC to EST timezone', utime.localtime(), '\n')
py = Pytrack()
l76 = L76GNSS(py, timeout=30)
chrono = Timer.Chrono()
chrono.start()
#sd = SD()
#os.mount(sd, '/sd')
#f = open('/sd/gps-record.txt', 'w')
while (True):

coord = l76.coordinates()
#f.write("{} - {}\n".format(coord, rtc.now()))
print("{} - {} - {}".format(coord, rtc.now(), gc.mem_free()))

Result:

Thank you very much to all of you who have had to endure my clumsiness and have helped me especially: @seb and @livius, include @crumble ! :-)

taking advantage of the post with the doubts and problems that I have had, I will shortly upload a guide in Spanish (since it is already in English) on the subject to facilitate other people.

[olliec]

@zceld I appear to be having a similar issue that you were having, with a LoPy4 and PyTrack.
My error however is "I2C bus error"..

I've updated the PyTrack to 0.0.8 (tried via Windows 10 and Debian) and LoPy4 to 1.14.0.b1, ran "os.mkfs('/flash')" and re-uploaded the files from a ZIP download of the Git (https://github.com/pycom/pycom-libraries).

This is what I get (I added the "print(e)" in pycoproc.py which is returning "I2C bus error"):

@zceld - was there anything else you did other than update PyTrack via your Mac?!

[zceld]

@olliec said in Lopy with pytrack, how connect/use GPS?:

was there anything else you did other than update PyTrack via your Mac?!

hello, well, you'll see that the only thing I did was really update, I attached the screenshots of what I did. I honestly do not know why you can fail, surely you can get a hand those who really know. The teachers who have guided me.

Screenshots:

Greetings, I will be here attentive to your problem to know how it is solved. luck.

[olliec]

@zceld :( yeah I think my error is different.. I'll start a new thread. Thanks anyways!

[zceld]

@olliec good luck!

[seb]

Hi,

I'm glad you got it working! The out of memory issue is a known problem with the GPS library on our older devices that have less RAM. This is due to the large amount of string data that needs to be processed. The advice is to retry a few times and once it gets a lock it will start working. This library will need to be improved in the future to try fix this.

It is very interesting that the update via windows didnt work but via mac it did, I will pass this on to the rest of the team.

Thanks,
Seb

[zceld]

@seb
Good afternoon, I just got back on.
Seeing that happiness is not forever. Since today again I have not managed to obtain GPS coordinates. I'm back in Windows, I'll mention it, but I do not think the problem comes from here. The story is that he always runs out of memory.

Is there anything I can do ?

[zceld]

@seb
Apart from the memory issue, I do not know how to solve it. I have other doubts to see if you can help me:

• Every time I run 'gc.mem_gree ()'. Am I occupying memory? More than anything because as you can see in the image is going down the amount of free memory, until I run 'gc.colletct ()' that seems to empty the cache. It is right ? Image:
  

-On the other hand, executing 'gc.collect ()' and then executing this code to obtain the coordinates, it seems that I avoid the full memory error, but instead it always stays that way and does not continue until I cancel. The doubt is that I do not know if it is because it does not find GPS today or what happens ...
code:

import machine
import math
import network
import os
import time
import utime
from machine import RTC
from machine import SD
from machine import Timer
from L76GNSS import L76GNSS
from pytrack import Pytrack
# setup as a station

import gc

time.sleep(2)
gc.enable()

# setup rtc
rtc = machine.RTC()
rtc.ntp_sync("pool.ntp.org")
utime.sleep_ms(750)
print('\nRTC Set from NTP to UTC:', rtc.now())
utime.timezone(7200)
print('Adjusted from UTC to EST timezone', utime.localtime(), '\n')
py = Pytrack()
l76 = L76GNSS(py, timeout=30)
chrono = Timer.Chrono()
chrono.start()
#sd = SD()
#os.mount(sd, '/sd')
#f = open('/sd/gps-record.txt', 'w')
  while (True):
     coord = l76.coordinates()
     #f.write("{} - {}\n".format(coord, rtc.now()))
     print("{} - {} - {}".format(coord, rtc.now(), gc.mem_free()))

[livius]

@zceld

Apart from the memory issue, I do not know how to solve it

use simple fix for this
https://github.com/pycom/pycom-libraries/pull/43/files

[zceld]

@livius said in Lopy with pytrack, how connect/use GPS?:

use simple fix for this

This solution and you told me about it and the thing is that you have to replace lines 74 and 75 with the lines that are in green, right?

[livius]

@zceld
Yes, but you have indentation problem
remember that python work on proper indentation.
nmea line must be indented

[zceld]

@livius said in Lopy with pytrack, how connect/use GPS?:

@zceld
Yes, but you have indentation problem
remember that python work on proper indentation.
nmea line must be indented

I suppose you mean this:

But then how do I fix it?

[livius]

@zceld

[zceld]

@livius

Perfect!. working correctly again. I do not understand how a tabulation can give an error. XDD it shows that I am new? Thank you very much again, although I'll probably come back with something else. But good Thanks to your patience as always.

[crumble]

@zceld

Is there anything I can do ?

You can try to call the garbage collector before and after you read the coordinates.

The better solution. Implement the GPS stuff by your own and share the code with us. You have to read the stream from the GPS chip into fix allocated buffers and parse them by your own. If you need only the coordinates, it is simple, you will need around 100 lines of code. I stuck with my version :-(. Had no time to work on it.

[zceld]

@livius
Well, I have another doubt. I am trying to send the coordinates by LoRa and it gives me the following problem that I do not know how to solve.

Other questions more:

print("{} - {} - {}".format(coord, rtc.now(), gc.mem_free()))

This returns (latitude, longitude) - (Real time clock) - free ram
But and the altitude?
The time can be updated?

[livius]

@zceld said in Lopy with pytrack, how connect/use GPS?:
touple is not buffered
you need bytes you can try to cast this as bytes() but for lora better is using pack.
look at samples about lora in official docs https://docs.pycom.io/

Time you can update from wifi connection
by e.g.

rtc.ntp_sync("pool.ntp.org")

or retrive it from GPS
or some external device for DCF or MSF

[crumble]

@zceld

But and the altitude?
The time can be updated?

If you look into the code of the library you will see, that only the coordinates are read from the GPS. No altitude and no dateTime.

The time information is read from WiFi. You will need access to an NTP server.

The sentence which is used to get the coordinates contains the time as well, but not the date. If you need only the time, you can simply add this to the library.

For date and time you have to add support for parsing additional NMEA sentences.

[livius]

@crumble
better use existing one
https://github.com/livius2/micropyGPS
and exctend it if needed