Carloop gps question

The connector fits what gps receiver?
I have one that is close… but it is not the same!

hey @macsboost, the GPS is the GP-735 (56 Channel) found at SparkFun GPS Receiver - GP-735 (56 Channel) - GPS-13670 - SparkFun Electronics. You will need a jumper wire like this one as well to connect it to Carloop: JST SH Jumper 6 Wire - 1.75" - GPS-00574 - SparkFun Electronics

What if you want to connect Carloop to Particle Asset Tracker, how would you do it?

There are ways you can do that, but I’m curious, what features of the Asset Tracker do you want to use? In other words, what is your project?

I just want to get some location reading off the Tracker since I don’t have any gps modules laying around. I’m gonna other the GP735 but now it’s a national week long holiday in Thailand.

I just got my GP-735. I couldn’t get a gps readings at all even Serial1 logging.


void loop()
  while (Serial1.available())  
    Serial.write(;  // pass RX data to USB serial

  while (Serial.available())
    Serial1.write(;  // pass USB serial to TX pin 

Please help.

I looked again at the PCB for the unit we shipped you and there’s a layout error on the GPS connector. The pins are backwards (1 is 6, 2 is 5, …).

If you’re able you can reorder the pins on the wire between the Carloop and the GPS unit. Lift up the white plastic tab holding the terminal with the tip of a knife and pull out the terminal. Reinsert the terminals in the opposite order.

We have another batch being produced right now that doesn’t have this issue. We can ship you a new unit when we receive it if you don’t want to re-pin the connector.

Sorry about that @Izeroman

I would like a replacement please. Please give me the address. Also instead of v. 2, can you send v. 3?

@Izeroman please send me a private message with your mailing address. V3 is not ready for production just yet!

1 Like

put me in line for a v3.
I ended up just deadbugging in another gps to make it go. The miswire makes sense now.

I would like to suggest using another gps unit anyway. These can be had for about $20 and include an i2c compass.
It is possible to use i2c for the gps as well, eliminating any serial port rate issues. They operate up to 10hz and are glonass/gps/beidou/galileo compatible.

Look for the pixhawk px4 compatible. Sirf also has a binary mode that has a lot less overhead than a nmea stream.

1 Like

This is based on the ublox m8n chip… the sparkfun was a ublox 7.

It’s rather unfortunate but one of the pins for the CAN bus is the same as one of the pins for I2C on the Photon. You could use an I2C GPS on the Electron since it has an additional I2C bus on C4/C5.

@jvanier Can I use this with both Photon and Electron?
This =

Yes, you can use it for both!

@jvanier, I just received my devices - is this pin reordering still required for Carloop R2.3 2016/05 and GPS GP-735T VRN 0.20?

Could you maybe also post an image of the correctly done done wiring?
And I hope the wrong wiring didn’t do any harm to the GPS module.

This is how mine looks currently (before reordering):

1 Like

The Carloop 2.3 has the correct wiring for the GPS. I did not see negative impact to the GPS module of the wrong wiring so you should be ok.

The picture you took shows the correct wiring.

Good luck on your projects!

1 Like

Strange then that I don’t get any GPS info with the carloop-minimal.ino sample - even after waiting for over an hour for a GPS fix (in car with clear view to sky).
I only ever get zero gps.charsProcessed()

As a side note, when having Carloop with and Electron and carloop-minimal.ino plugged into my Renault Espace (2007) it won’t start and always complains about oil pressure loss :flushed:
Removing Carloop cures the problem :wink:

Let me take a look on my end if anything changed recently with the GPS setup and I’ll get back to you.

@jvanier, after some messing with my other problem, unplugging, replugging GPS module and Particle devices, I now do get GPS readings.
No idea what cured it, but that’s settled for me now (with the original wiring).

1 Like

whew! that’s fantastic news! This is a new batch of GPS + wiring so I’m glad to hear that. What do you suspect was the issue? Can you reproduce it at all?