Powering Pytrack + Gpy without USB - How to connect?

[jpgamboa]

Hello everyone.

From other posts in the forum I realize that it's possible to power the Pycom modules via the VIN and GND pins but the information is very fragmented and I'd like to clarify some aspects of this option for myself and others in the future:

1. Connecting 5V to the VIN pin will power both the Gpy and the Pytrack (and it's GPS module, SD card...) without issues?

2. How are people achieving this connection?

   • By soldering to the pins on the Gpy from above?
   • By soldering to the pins on the PyTrack from below?
   • Somehow connecting to the pins where the Gpy meets the Pytrack?
     .

3. Instead of using the VIN pin, is it possible to power the device directly from the battery connector with voltage coming from a step-down dc converter? If so, should this be done with 5v or 3.7v?

Hopefully someone can answer this.
Thank you!

[Gijs]

I can understand your confusion. There's some slight differences between boards, and it also depends on what you want to achieve.

1. Using the Vin connection
   Powering the device from the Vin pin will power the Gpy and GPS, but not the PIC on the Pytrack, meaning you will not have USB (this is because the Pytrack includes a power switch, allowing to turn off the power to the Gpy, and thus the Vin is located after this mosfet switch). Though this would not be a problem in your application I presume? Except if you want to use the py.go_to_sleep() method, for which you need the PIC powered.

2. Using the battery connector
   It would be possible to power the device through the battery connector with 3.7V, which ties into the Vusb voltage. Though I would be hesitant there, as there is a battery charger on the other side which does not expect voltages above 4.2V. There is an on-board switch that selects the voltage source there, and if Vusb is applied, Vbat is disabled.

I would suggest you use the test pads labelled Vusb_AUX for a 5V connection. There's test pads close to the Pyport connection that allow for this. In this case, do not supply both the USB and this port at the same time. I'll make this more clear in the documentation

[jpgamboa]

@Gijs ,

Thank you for such a quick reply.

For my use case, I plan on having the device running for as long as there is power coming in. (vehicle tracking)
So I don't need to send the device to sleep and I don't need a battery.

My goal is to provide power from the step-down dc converter to the pytrack without using USB, as using USB connectors would have a large footprint on the case.

Using the VUSB_AUX looks like a good alternative.

If you could clarify, does powering through the VUSB_AUX allow for battery charging or is it similar to powering through VIN?

[Gijs]

VUSB AUX does allow for battery charging. It is exactly the same as plugging in a USB cable to supply voltage.

[jpgamboa]

Just to give feedback,

I've had the Pytrack + Gpy powered via the VUSB_AUX for a few hours and all is working fine.

Thank you for all the help!