2020 Nov 09
Nice tutorial using ESP32 and 4.2 " e-ink display
Associated library, GxEPD is here
Link for project code in the tutorial is here
|Heltec Wifi LoRa v2 pinout.|
Instructions for Adafruit MicroSD are here.
Formatting a microSD tutorial here
Convert to byte array code here
converting input images to proper grayscale here
this conversion pipeline looks great -- here
which is explained along with other code here
Code on github is here
Great little tutorial here
convert Lenna.png -monochrome lenna-1.png
convert lenna.png -monochrome -resize 200x320\! lenna4.bmp
Good quality compass offered here
Typical map tile size is 256x265 -- reference here
Guide to creating your own tiles here
Browsing local tiles guide here <---- this seems like a great guide to dive into.
More basic guide to OSM tiles here.
Design considerations for UBlox here
|Fig 9 from the UBlox App Note mentioned above.|
Nice discussion and review here
Main project description is here.
Open map tiles project update is here
OMT is compatible with Stamen's Toner -- post here.
Thread discussion here.
Doing it without dithering:
convert bone.png -colorspace gray -threshold 80% -type bilevel -resize 200x320\! bone4.bmp
Link to waveshare guide for 4.2 in e-ink here
Datasheet is here.
There's a nice description here.
Tutorial on using ESP32 deep sleep here.
In particular, wakeup from external pin here.
E-Pulse project is [here](https://thingpulse.com/product/epulse-low-power-esp32-development-board/#:~:text=ePulse%2C%20the%20low%20power%20ESP32,and%2035uA%20(at%2012V).
Arduino APRS project, here.
Key project. Marinus, and APRS display project, here. Great set of links, here!
Online code to generate OSM tiles for download is here.
Source code for generating tiles from OSM is here
Grid square locator on above site is broken; perhaps this works?
Grid square locator here.
Computing lat / lon here.
Conant road lat / lon: 42.41158 -71.2983
Grid square utility here works, but doesn't give 10 character grid squares ...
Another tool is here, which generates a nice overlay ... <-- this is the tool to use!
So, the combined tools are:
Example grid square:
Reference on gridsquares here
Ham radio chat on grid squares here.
General term for this is the Maidenhead Gridsquare System.
(Alternative: the World Geodetic System)
Nice explanation of the grid locator system.
Nice historical background on the system.
Really nice video explanation of grid squares.
Guide to tiles here.
Tutorial on how to use OSM tiles in an application, here.
Leaflet providers here <-- really useful survey of free tile providers.
Good list of hiking maps
Would be nice to include the GridSquare system in an offline map. Easily switch between a device and a paper printout.
How would one overlap on a 'regular' map? Might be neat to try to do via features. Would need same project I suppose.
Note that there's a TTGO EINK+ESP32 module here.
E-ink calendar display project here for ESP32.
If custom board:
can sell for 4X to support project, or around $200?
If DIY kit:
Can sell the PCB + SD card + GPS + screen as a kit for (10+30+5+5)*4 = $200 ... hmm. Maybe if also sell a case ...
Sparkfun ublox library.
Various Sparkfun ublox products.
I think the cheap chip vis a vis ublox is the NEO-6M. That's on the meshtastic, and that's what I'm using via Amazon. E.g. here.
This is the 'NEO-6M' item I've been using, here.
Module description is here.
Dimensions of module are thus:
Sparfkun thumb slide joystick.
Two-axis analog thumb joystick from adafruit.