Comments: SparkFun RTK Express Hookup Guide


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #333735 / about a year ago / 1

    Has anyone been able to successfully use the Sparkfun RTK devices using iOS? It seems the only connection option is bluetooth SPP, which iOS does not support

  • Member #1534665 / about 2 years ago / 1

    The hookup guide for the GPS device suggests using a radio solution that's now retired. Could you update that please?

    I see that you have a kit that seems to do a similar job:, but I see a comment that says "In order to use the Serial Telemetry Radio Kit, you'll need to cut the one of the provided JST-GH cables in half and tin the ends (for insertion into Arduino headers) or solder the connections to your remote unit". Will this kit work with the GPS unit out of the box?

    • I know - sorry about that! The vendor has assured us they would have stock by now so I was hesitant to rip out that content only to have to add it back when the new version of the radio comes out. I'll take care of it.

      Yes, the 100mW radio is identical to the 500mW radio in every way except power output. Pretty much any serial radio will work (including those on ebay/amazon) but you'll have to identify the TX/RX pins correctly.

  • ddegn / about 3 years ago * / 1

    It would be nice if the pinouts were labeled better in the diagrams .

    Edit: The phrase "highlighted photos" would probably be a better description than "diagrams." Below is some clarification. The Hardware Overview\Connectors\Radio: section includes the following text:

    The pinout is 3.5-5.5V / TX / RX / GND. 3.5V to 5.5V is provided by this connector to power a radio with a voltage that depends on the power source.

    The Data: section includes similar text:

    The pinout is 3.3V / TX / RX / GND. 3.3V is provided by this connector to power a remote device if needed.

    The RTK Express includes a connector with wires which can connect to these locations. The included wires use red for the power line and black for the ground line. These wires can be used as an aid when making a custom wiring harness. Unfortunately, I didn't use the included wires as a guide and I reversed the order of the lines in my custom harness. Reversing the order swaps the power and ground lines. Fortunately connecting a radio with reversed power causes the less expensive radio to go up in smoke and not the expensive RTK Express device.

    I built my own wiring harness to connect the RTK express to some cheap telemetry radios I had on hand. I built the harness while watching YouTube videos. In hindsight I should have double checked the wire order.

    Maybe if the diagram had been a bit more explicit about the pinouts, I wouldn't have smoked one of my telemetry radios. Yes, the burned out radio is completely my own fault.

    On a bit more reflection, the Hookup Guide is probably just fine as it is. Hopefully my pitiful story will help someone reading to double check their wiring and not destroy any innocent hardware.

    Thanks for making so many great tutorials SparkFun. SparkFun has been a very important component in my electronics education.

    • santaimpersonator / about 3 years ago / 1

      I tossed in a note clarifying that the pins mentioned are from left to right in the pictures. I also linked to the Advanced Features section because users can actually see the pins broken out and labeled on the board.

If you've found an issue with this tutorial content, please send us your feedback!