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A project log for Light level geolocator

If you have a lot of time, you can decide your position on Earth just using watches and eyes. Or RTC and LDR.

jaromir.sukubajaromir.sukuba 01/08/2018 at 21:462 Comments

Though started 12th of December - less than month ago - this project was funny a rewarding one. From beginning I knew there will be a few weak spots I have to addres:

Despite that, I've been able to make 6 light loggers, five of them being sent across the Europe, being ready to collect data which served as basis of my geolocation algorithm setup. After I succesfully received four of them I honed the algorithm, discovered some peculiarities making my life harder, but at the end I validated my ideas and established approach to use on real LLG.

In the meantime, I designed and made the LLG hardware. Because I had no time to wait days or weeks to collect reasonable amount of results from LLG measurement, I implanted data previously measured by simple loggers into LLG as if it were measured by LLG and observed results, being surprisingly good considering how trivial is the measurement method, even proving some degree of robustness against unsuitable conditions.

At the end I calculated projected battery life, being 10 years with display on and 30 years with display off - just running geolocation and logging the location points.

Firmware, PCB files and 3D files are available on github.

LLG has error of, say 100km versus 10m for GPS, ie. four orders of magnitude worse accuracy. On the other hand, commonly available GPS units have consumption in order of tens miliwatts, while LLG can track and log its position with consumption of microwatts, that is four orders of magnitude less.


Discussions

bobricius wrote 01/12/2018 at 20:01 point

DS3231? I am using it daily. Display is best part of this device. I want make wrist watch with this display but never used LCD, only LED displays, also I have no experience with PIC :( I am using BPW34 diodes as solar cells. https://www.youtube.com/watch?v=8XubLl-EHh4

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jaromir.sukuba wrote 01/09/2018 at 10:52 point

Somebody asked about compiling sources - they are designed to be opened by MPLABX and compiled using XC16 compiler. Both are free to download at microchip website, just run two executables are you are set. People insisting on not using MPLABX can surely adjust the makefile to their needs.

While both are free as for zero dollars, XC16 has actually sources available and is one is able to persuade it to behave like full version, see more here https://hackaday.io/project/27250-mcu-how-tos-reviews-rants/log/72734-exploring-microchip-xc16-compiler

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