Heltec esp32 Lora v3 + GPS

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1

I just got a pair of stock Heltec Lora v3 boards and they work fine with GPS info from Bluetooth connected smartphones.

I’d like to use the heltec without the phone and add a ublox neo6 compatible GPS module.

My question is : using the already compiled and installed firmware , which heltec pins should I solder the GPS TX and RX leads to?

Also, where are the pin assignments defined in the src? I looked in configuration.h but didn’t see anything.

Many thanks for reading and hopefully answering…

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2

Looks like you should be able to connect to GPIO 2 and 3 according to this: Enable GPS capabilities on heltec V3 by ghostop14 · Pull Request #2039 · meshtastic/firmware · GitHub

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thanks. Does this mean I need to flash the firmware contained in the zip file ? or am I ok just to connect the GPIO 2 and 3 and set Device settings>Position Config : GPS Enabled , Redefine GPS_RX_PIN = 2, Redefine GPS_TX_PIN = 3 ?

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You would need 2.0.8 or later as the gps wasn’t enabled until that release.

5

Many thanks for your help. I’ll give that a try when my GPS arrives.

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6

good info. Just got my v3 boards in today and waiting on gps modules myself too!

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7

GPS modules arrived and I hooked it up and it works!! Just to be clear , meshtastic’s ‘Redefine GPS_RX_PIN’ is the pin number on the V3 for connecting to the GPS module’s TX pin.

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8

how many more mAs does it need???

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9

Does anybody know what’s the best way to power the GPS-Module?
I have connected:

  • [+5V Heltec Lora v3] → [VCC GPS-Module]
  • [GND Heltec Lora v3] → [GNS GPS-Module]

This works as long as I connect my [Heltec Lora v3] with USB
But when connecting a battery to the Lora Board, then the GPS-Module won’t start.

10

Ok, Reading the Datasheet of the Heltec LoRa v3 Chatpter “3.3 Power Output” helped:

I needed to connect the [3v3 Pin] of the LoRa board to the [VCC Pin] of the GPS Module.
The datasheet says, that the 5v PIN on the LoRa Board is only USB powered.

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11

Yeah I didn’t see this yesterday but that’s what I would have said too, ran into the same issue myself lol. Glad you figured it out!

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12

Does anybody know if it makes sense to connect (TX-LoRa) → (RX-GPS)?
If yes, what would the LoRa-Board send to the GPS-Board?

I only connected (TX-GPS) → (RX-LoRa) and everything seems to work perfectly fine.

13

What text is displayed on Heltec screen when it is unlocked and locked?
My screen still says "No GPS "
I have the TX of the GPS connected to GPIO Pin 34.
The Redefine GPS_RX_PIN set to 34 in Position Config
Using a GT-U7 module - It’s still flashing red.