As I wrote at the beginning, I started my own GPS logger development for the following motivations. I put marks for my currently developed GPS logger.
|Easier log extraction||✓||GPS log is now a regular file!|
|QZSS support||✗||Only 1 of 4 satellites supported.|
|Much larger log memory||✓✓||Modern SD card sizes are virtually infinite for GPS log.|
|More compact than smartphone||?||Compact but still larger than M-241.|
|Longer battery life than smartphone||✓||Lasts for a whole day while logging every second.|
As you can see, there are two points to improve: QZSS support and physical size.
Consideration on QZSS Support
I looked for other GPS receiving modules for QZSS support. However, I cannot find anything other than the current one (Global Top PA6H).
Maybe I could develop receiving module from bare-bone receiving chips like MT3339 or ublox 6. But considering that my current logger captures as many satellites as 8 or 9, which is well above required to get position fix, it is not worth trying.
Someday, when companies like Adafruit or SparkFun releases newer GPS receiving module, I would consider to replace.
Consideration on Physical Size
As you can clearly see, the current green pill case is quite roomy for my GPS logger. I considered two options for smaller case as below.
- 3D printing original case.
- Searching smaller case.
For option 1, the biggest barrier is 3D modeling. I have no experience in 3D CAD. I tried FreeCAD just for a while and found 3D CAD is way too difficult and time consuming.
For option 2, there is a great case manufacturer Takachi here in Japan. See its home page for very wide variety of cases. I looked through its PDF catalog, but surprisingly, the best one is almost same in size as the current green case.
Also, I found that the current case isn't too big if I can put it in a bag.
Conclusion for Now
I will conclude the development with big satisfaction. I may rewire with shorter cables.