Alex's Corner - Week 7 - Pytrack, GPS & more!

[PiAir]

It might be out of the scope of you demo, but I am currently looking at ways to send GPS coordinates of a LoPy to the TTN network.
As you know, for TTN / LoRaWAN you want to encode the data you are sending as efficient as possible because of the limitations in data that you can transmit.

I have found a discussion and code suggestions on the TTN forum to send them, I still have to convert the provided code to microPython before being able to use that on the LoPY though. Bitwise shifting is one of those lovely topics related to data transmission. :)

Anyways, just thought that I'd mention it as something that people struggle with related to GPS>

*p.s. I am not using the Pytrack, but the regular Expansion Board together with a 7 euro external GY-NEO6MV2 GPS receiver over UART, works like a charm.

[RobTuDelft]

@PiAir Sounds like a nice topic for one of your blog posts? :)

[PiAir]

@RobTuDelft Once I've got it working, I'll of course blog about it, time is a bit limited though, life is requesting some attention also at the moment.

[bucknall]

@PiAir Absolutely! I know there are some clever means to reduce your payload size - so I'll discuss some of them in my video next week! I'm currently working on a library that compresses GPS values for LoRa/Sigfox/etc.

[PiAir]

I wanted to combine the use of GPS with logging to the SD-card, but ran into problems setting the RTC. I didn't always get the needed date/time info from GPS (don't know if the Pytrack does that better :) ) and ran into problems setting the RTC using NTP (could be that it is fixed in the latest firmware version, will have to document my project first before I can test the upgrade).

But combining GPS-tracking with writing to SD card would be another nice use-case. :)

[bucknall]

Quick Update - Looks like I'll have to delay this Alex's Corner until next week when the Pytrack/Pysense arrive (see - https://forum.pycom.io/topic/1208/pytrack-pysense-delivery-status-latest-info).

Instead, I'm planning to do a 'best practices for deployment' so looking at disabling radios when not in use, when to put the device to sleep (once the deep shields/pytrack/pysense arrive) as well as changing default passwords and using secured sockets for communication, amongst other techniques.

I'll squeeze another Alex's Corner in next week to align with the Pytrack & Pysense release dates!

Thanks!

P.S.

@PiAir, have noted your issue and am looking into it for you!

[felirangelp]

@bucknall Do you know what happened with this video? I can't see this video.

[bucknall]

Hi @felirangelp, I've unfortunately been super busy with events and helping with the libraries (as well as a new documentation project!) I didn't manage to get around to uploading the video yet!

I'm finally back to normal schedule so Thursday I'll put it up then!

Thanks for your interest!

P.S. Did you want to see anything in particular, in a future video? :)

[robmarkcole]

@bucknall how about setting the Pysense up as a web/flask server?

[Jiemde]

@bucknall Waiting the video this afternoon!
I have a question: what's the difference between the machine.deepsleep() and the pytrack setup_sleep() + go_to_sleep() ?
Is the read_battery_voltage() is working, because I read already the same measure event in usb or Lipo powering ?

[bucknall]

Hi @Jiemde,

The difference between machine.deepsleep() and pytrack setup_sleep() + go_to_sleep() is that the first uses a Pycom device (i.e. LoPy) to control the sleeping procedure. This currently doesn't work on the existing batch of LoPy, WiPy 2.0 and SiPy development modules but does work on their OEM counterparts.

The read_battery_voltage() does work, however you must update the firmware on your Pysense/Pytrack to the latest version (https://docs.pycom.io/chapter/pytrackpysense/installation/firmware.html) in order for this feature to be enabled!

Thanks,

Alex

[Jiemde]

Hi @bucknall
Read somewhere that the deepsleepshield is incorporate on the pytrack and pysense board ! am I right ?

[bucknall]

@Jiemde This is correct! They use the same sleep method as the deep sleep shield to control the devices sleep. I.e. setup_sleep() + go_to_sleep().