Propeller GPS

3dogpottery · 2019-03-28 17:58

In order to learn about GPS and how they work, I purchased a cheap
Satellite Positioning Module on eBay. I wanted to try and communicate with
it using Parallax’s Propeller microcontroller. I was able to parse and
display NMEA sentences on a serial terminal, but thought that with the
addition of a display module, I could make a portable GPS unit. The results
are what I call the "Propeller GPS". I uploaded the whole shebang to the
Parallax Objex Exchange. Just look for "Propeller_GPS". Both the GPS and the
display module can be purchased on eBay for about $8.00 each. I used a
Propeller Mini because of its small size. All this can be mounted
in a small enclosure with a 9V battery. This was a very fun project and I
hope you find it so too!

Publison · 2019-03-28 19:43

Nice project!. With a couple of pictures and links to the program and products used, we can include that in the "Customer Projects" page. I can help with that.

I believe this is the GPS module used:
https://www.ebay.com/i/303105342240?chn=ps

And the OLED:
https://www.aliexpress.com/item/0-96-inch-IIC-Serial-White-OLED-Display-Module-128X64-I2C-SSD1306-12864-LCD-Screen-Board/32896971385.html?src=google&albslr=225519109&src=google&albch=shopping&acnt=494-037-6276&isdl=y&slnk=&plac=&mtctp=&albbt=Google_7_shopping&aff_platform=google&aff_short_key=UneMJZVf&&albagn=888888&albcp=1582410664&albag=59754279756&trgt=296904914040&crea=en32896971385&netw=u&device=c&gclid=Cj0KCQjw4fHkBRDcARIsACV58_GjKrV9Q1YejLlcH9tEH-mMzorWgEMHQqIRNU5qFDvwcbqpV0F06C8aAp9OEALw_wcB&gclsrc=aw.ds

3dogpottery · 2019-03-28 21:02

You are correct. They are the modules used. However, the .96 inch OLED I purchased on eBay is labeled VCC, Gnd, SCL and SDA. You have to be careful with some of the modules from China. I've seen several that say communications are I2C when in reality they are SPI. Here is a link to the one used in my project:

https://www.ebay.com/itm/0-96-I2C-IIC-Serial-128X64-White-OLED-LED-Display-Module-for-Arduino-SSD1306/391742247377?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

JonnyMac · 2019-03-28 22:05

Neat. Sometimes I will look at a program and wonder I I would do things differently. One example is the tx() method -- I think this streamlines it a bit.

pri tx(ch) : idx

'' Send character ch to OLED

  case ch
    "0".."9":
      send_byte(@0 + (ch-"0"))

    "A".."Z":
      send_byte(@A + (ch-"A"))

    other:
      idx = lookupz(ch : " :.&,-")
      if (idx => 0)
        send_byte(@Space + idx)

3dogpottery · 2019-03-30 13:54

Thanks for the input Jon. I plan to write a stand alone module expressly for writing to the OLED. I found that communicating with the GPS unit was pretty straight forward. Writing to the OLED was a royal pain. The datasheet for the SSD1306 is written in Chinglish and I had to re-read sections about 100 times before some of it sunk in. And one must be careful with the cheap .96" 64 x 128 OLED modules from China. Some have VCC and GND backwards. I found that the 1.3" version of this OLED is actually driven by the SH1106 controller even though it is described on eBay as having the SSD1306 controller. And the screens are actually 64 x 132. On another topic, after reading the datasheet for the SH1106, it seems that the only difference is that it controls OLED screens that are 64 x 132 pixels in resolution. However, try as I might, I can't seem to put the damn thing into "Horizontal" address mode. In order to clear the screen, I have to keep it in "Page" address mode and write zeros' to each page in turn.

3dogpottery · 2019-04-02 22:05

Hey Jon: I tried some of the code you posted and found it very helpful. The "lookupz" I think you might have backwards in terms of "idx" and "ch". However the rest of your suggestions were brilliant! It really shortened my code!

macrobeak · 2019-04-03 01:06

3dog,
I am glad you optimized your code.
Can I ask if you have incorporated this improvement in your OBEX object 906 mentioned in the other post?
Keep up the good work. A cheap user-friendly text display is great for project debugging and as a live implementation display.

3dogpottery · 2019-04-04 00:39

macrobeak wrote: »

3dog,
I am glad you optimized your code.
Can I ask if you have incorporated this improvement in your OBEX object 906 mentioned in the other post?
Keep up the good work. A cheap user-friendly text display is great for project debugging and as a live implementation display.

Yes I have.

Propeller GPS

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