Simple Propeller GPS status display

If you’ve ever wanted to know how many GPS satellites are receivable at your location here’s a good beginneer’s Propller project that provides the answer. Its a GPS status display project Nick Ernst developed written in SPIN code and using a Propeller Mini Board, VPN11513 GPS Receiver, shift register and 7-Segment LED display. “The Propeller Mini Board talks to the VPN1513 GPS Receiver and converts the received data to usable values that you can use in an application of your choosing. In this case, we are looking at the “Signal Validity” and the “Number of Satellites” strings from our GPS unit and converting that data into a visual representation through two LED’s and a 7-Segment Display.”

Full details, schematic and SPIN source code can be found at Learn.Parallax.

Join the Conversation


  1. The Propeller Mini board is nice and small, and the propeller can do things some other basic uC chips cannot (like synthesize a VGA signal directly, bitbang / timer at 80 – 100 MHz, 32 bit wide port, etc). If you want to learn Propeller coding that’s fine. I just note that board is $25, and for simple lower-speed tasks like this example, I’d think something like an Arduino Mini (less than $4 shipped from ebay) would be more cost-effective. The bare Propeller chip by itself ($7.99) is more than twice the price of a fully-functional Arduino Mini board. See for example, ebay item 271251071444

  2. I don’t understand why they’re driving the 7-segment display via a 74HC595 shift register. There are plenty of pins to drive the display directly. Maybe the 595 is there as part of the tutorial…

    1. There are many possibilities:
      – They do this out of habit.
      – They had a 7 seg library from a previous project… you never know when you’ll need to add more displays.
      – They have features they haven’t added yet.
      – They have always wanted to use a 595.
      – They felt like doing it this way.

      I agree that they have the pins, but, it is possible that they just mocked this up and aren’t going to keep it past the blog post.

Leave a comment

Your email address will not be published. Required fields are marked *

Notify me of followup comments via e-mail. You can also subscribe without commenting.