Portable GPS Box
I was looking at the Ultimate GPS from AdaFruit, and decided to see if I could get it working without a huge effort. The last time I worked with GPS was a bunch of years ago. So, the Ultimate GPS has some pretty nice parameters, basically, the MTK3339 chipset on a nice breakout board, can track 22 satellites on 56 channels, with a sensitivity of -165 dB tracking. Plus, the version 3 has a uFL connector, so with a uFL-to-SMA adapter, an external active antenna can be attached. A coin cell battery (CR1220) holder is also included.
The enclosure was created with OpenSCAD, sliced using Ultimaker Cura, and printed with a 3D printer, using PLA. I wanted to use the Pimoroni Pico Display Pack 2.8 for plenty of real estate for large numbers. A bit of eye candy never hurts…
I also decided to include a BME280 weather sensor, handy for instant conditions in the field. This gives everything necessary for a fairly accurate location and altitude reading, while providing the current weather conditions. To power everything, I used a Lithium Ion 3.7 volt battery at 4400 mA capacity. So, to connect the battery to the Pico, a LiPo Shim is required, which mounts on the Pico pins, while still allowing room to mount the Pico on the bottom of the Pico Display Pack 2.8.
The above image shows the parts locations. In the box bottom, at the left is the battery, and the other end is the weather sensor. Directly above the weather sensor is the uFL-to-SMA adapter cable, exiting the box side for attachment of an external GPS antenna. The box top contains the Pico Display Pack, with the Pico and shim plugged in. The right side is the Ultimate GPS module, with the built-in antenna facing up when the box top is in place. All the parts are secured with hot glue, a great sticky solution to parts placement.
Having described all that, above is the final result, showing all the data needed for home or the field, including the time. All the data used is from the GPS GPGGA sentence. Notice the external GPS antenna cable exiting the box.
So, another project is completed. Nowadays, projects like this are accomplished much easier because of the availability of modules. If a person had to create the same project using only discrete components, the result would be a rather large bulky item!
We thank God for the ability and knowledge to create something like this, as a hobby, and for the parts availability. Praise God!