Faulty Electron Asset Tracker Shield?

[Derek]

Hi there,

I am playing with my new asset tracker kit and I’m wondering if the shield is faulty. I’ve lined up the labels on the shield with the pins on the Electron, and ensured it is seated well.

I’ve installed the “gps features” demo app on my electron and have verified I can call “batt”, “gps” etc. It is calling enable() and gpsOn() on setup, as well as updateGPS() on loop.

However, the thing never gets a fix, and the “gps fix” light never blinks, even once.

Is it possible my kit is faulty? Do you have any recommendations? I’ve seen recommendations that pulling D6 to low turns on the shield – I’ve tried doing that with a custom script, but see no changes.

[Moors7]

Where exactly are you trying to get a fix? Indoors, reception will be bad. Just making sure

[Derek]

I’m trying outdoors, but the datasheet says the “GPS Fix” LED should blink red once per second while trying to obtain a fix – and I’m never seeing anything light up on the shield

[harrisonhjones]

Can we get a picture of your shield with the Electron plugged in and the power connected? Just to verify that everything is in the right place.

[Derek]

My understanding is that the Asset Tracker shield should be powered by the LiPO battery. Is that correct?

[ScruffR]

Can you try to flash this sample from the AssetTrackerRK library
https://build.particle.io/libs/57e98f06d94585ab81000aa9/tab/1_SimpleGPS.ino

And yes, the Electron LiPo will power the shield - the coin cell is just there to provide backup power to the GPS module to save any already downloaded satellit dictionaries to speed up fixing time.

[Derek]

Thanks @ScruffR, I just that… Serial1.available() is never > 0. I don’t see any lights come on when D6 is pulled low.

I can’t visually see any damage or anything wrong with the shield. Are there any common issues like this that anyone is aware of?

[ScruffR]

Can you double check that your code is actually running on the Electron?
e.g. by adding some blink D7 code.

How are you building and flashing?

[Derek]

@ScruffR I’ve done that, as well as added a bunch of logs to verify the state of the program. The program begins listening on Serial1 but no data ever becomes available, and the GPS doesn’t seem to power on.

I got this particular electron with the AssetTracker as a combo, so I’ll try it with another Electron which I know to be working, just in case its the Electron itself. It definitely appears that the shield is just broken.

[ScruffR]

Maybe then it might be time to file a support ticket and refer to this thread.
Trying another Electron (or even Photon, if you have) could help to tell who’s the actual culprit - shield or controller.

[BDub]

@Derek if you programmed that example, it should blink the GPS fix LED as stated. If not, the GPS unit is probably not getting power. Either a problem with the D6 output not going LOW (electron failure) or the shield hardware not working correctly to turn on the GPS module. There is a mosfet that controls it.

If you don’t have a multimeter, you can use the D7 led on the electron as one. Just make sure you are running that example app from above and NOT controlling the D7 LED as an OUTPUT … it needs to be an INPUT and then you can apply 3.3V to that pin and light up the LED.

See here where to touch:

You can also try manually pulling D6 low with the electron in RESET.

If this doesn’t work, the shield is faulty. If this does work, the electron is faulty.

Either way, after figuring out which one please work with Particle Support to get a replacement. Thanks!

[Derek]

Well, it looks like it’s officially the shield. I double-checked that connecting the jumper wire to D7 and 3v3 turns on the LED, but connecting to D7 and the VIN pin of the GPS module as shown above does not.

I also verified again with logs and Particle functions that D6 is pulled low and it’s trying to communicate with the GPS.

Thanks for the tip for diagnosing it! I’ll reach back out to Particle support next