Pycom + Pytrack - various questions

  • Hello

    I've been doing alot of research on the Sigfox network and Pycom products. I am wanting to build a GPS tracker which will is compatible with RC4.

    I require the GPS tracker to wake up when movement is detected and parse co-ordinates (latitude/longitude) to the Sigfox network.

    Given the amount of support for Pycom, I think the best product for my purpose is Pycom LoPY4 + Pytrack.

    A few basic queries before I get started (Apologies if my queries about Sigfox are outside the scope of this forum):

    1. Assuming the GPS tracker is always running and transmitting back to the Sigfox network @ 140msgs per day, what is the expected power consumption (i.e. mAH) for the Pycom LoPY4 + Pytrack?

    2. What is the ambient rating for these chipsets before they fail?

    3. I've read alot about loss of GPS signal with the Pytrack unless it has visibility to clear sky. Have they developed support for an external aerial? Are there alternative devices out there which will work better indoors (suited to the Sigfox network)?

    4. Is there a front end interface which can read the GPS co-ordinates and automatically placed them on an interactive map (i.e. parsed through the Sigfox network)?

  • @pyshi were you able to connect the adafruit gps to lopy4 ?

  • @jcaron said in Pycom + Pytrack - various questions:

    GPS is not designed to work indoors. If you need indoor positioning, you need a different technology (usually based on Wi-Fi network scanning). Not sure if Sigfox can be relied on indoors.

    Sigfox shall offer a location service as well.

    You need good maps for locating by WiFi/Bluetooth. You have to place the sender well planned, so your device is not fooled by reflexions and shadows.

    GPS repeaters exist as well. But I have no idea if there is a region where they are legal and how detailed the position is.

    Using sigfox for location transmission sounds like the OP has no controll about the hardware. So a mix of GPS, sigfox and WiFi location sounds OK. So it will be a mix of getting a location by last GPS and actual sigfox position. Than have a walk in that area and find a matching WiFi setup.

  • @pyshi How much power is used depends a lot on the chip used (i.e. the one included on the Pytrack or another one), how often you use it and a lot of settings.

    As an example, the Quectel L76-L used on the Pytrack used between 19 and 29 mA when active. There are various power saving modes, or you could switch if off and switch it back on when needed to reduce this, but the parameters will depend a lot on your use case.

    The LoPy 4 itself uses anywhere between 40 and 200 mA depending on what it's doing (just active, listening, transmitting, etc.). Again, there are power saving modes, but whether you can use them, how you do, and how much you save depend a lot on your use case.

    In the best case you could have the whole setup in deep sleep most of the time, waking up once a day to get a position fix and sending it, which would enable you to get an average power draw around 100 µA.

    If you do the same but wake up every 5 minutes instead, your average will probably be in tens in mA instead.

    That means that will a relatively large 2500 mAh battery, in the first case it lasts a couple of years, in the second case a few days.

    Note that instead of fixed time intervals, you may use movement detection using an accelerometer (or combine both, doing frequent updates when movement is detected, and very few when not moving).

    GPS is not designed to work indoors. If you need indoor positioning, you need a different technology (usually based on Wi-Fi network scanning). Not sure if Sigfox can be relied on indoors.

    When you use Sigfox or LoRaWAN, you don't read data from the device (it's not listening), it's the device that sends data based on whatever triggers you set up in your device. The data is then stored in a database, and you use a front-end to display that data.

    I've never used any off-the-shelf components for that, but I'm pretty sure there are many, though which ones may be suitable depend a lot on what you need exactly (the last received position, a track of the positions received over time...).

  • I've done a bit more digging and found the Adafruit Ultimate GPS Breakout - 66 channel which seems to support an external aerial and can talk to the Pycom LoPY4 chipset.

    Has anyone had any experience with this chip + external antenna and integrating it with the Pycom LOPY4?

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