Config for my moto harpia to turn it into a bike computer. We will
need

- working gps
- bluetooth (ble) stuff
- wayland "cage" compositor
- an app
- rsync service so that trails can be downloaded to a computer
- ip connectivity with flight mode
 - give it telent and dandroid as APs
 - use rfkill aggressively to save battery
 

Absent any reason I should not write the app in fennel I'm going to
write the app in fennel. I want it to

- display speed/cadence/time of day/power
- show where I am on a map
- record trail of where I've been (note: indoor counts too)



can we somehow do non-flakey bluetooth (is it dbus?)



cool extras
===========

adjust screen brightness 

* turn off backlight when stopped after a minute
* dim the screen when following a route and the next
 navigation instruction is still some way off
* tap to wake screen

note that IPS LCD requires as much battery for dark pixels
as light ones, so we get no power saving by colouring only part
of the screen


------

random notes follow ...



https://git.syndicate-lang.org/tonyg/squeak-phone/raw/commit/474960ddc665ed445a1f5afb0164fe39057720f9/devices/pine64-pinephone/modem-docs/80545ST10798A_LM940_QMI_Command_Reference_Guide_r3.pdf



1) [done] connect Satellite to qmi-nmea

https://codeberg.org/tpikonen/satellite/src/branch/main/satellite/nmeasource.py#L106

2) [nope] do we need modemmanager? might be required if we want lte data,
but that's up to the "site admin" - we don't need it for biscuit itself

3) we should make saturn give visual feedback while it's loading an
app. How does it know when the app has finished loading?  Maybe it
could get told when its window is obscured

4) rename Maps to soemthing that describes its role better. Cockpit?
HUD? (but it's actually H Down D)  Head Unit? Navigate? Dashboard? Cluster?
Codriver? Satnav? Binnacle? Launch? Ride? Embark?

5) [all done]
Maps also needs to open the nmea port and parse data from it.
5a) Maps needs to open a fake nmea source for testing
5b) we need a generator of fake nmea data

6) Cockpit
- show [done] speed and [done] direction
- show speed limit
- [done] scroll and [not done] rotate map
- overlay planned route on map
- show next turn
- voice prompts
- when off-course, calculate route to nearest point on course
- fetch planned route from nominated url
(don't want to type the url in, is there a better way to have it check in
with a mothership?)
- save trail (maybe this could be a separate task entirely)

elapsed time: what should it actually show? moving time, I guess
- moving time since when?

should we rename bearing as course in nmea?

rotating the map is going to be complicated because the widget we're
using doesn't support it (bitmapped map tiles)



perhaps we need a server-side component for route planning


7) think about how to use nfc tags or something for profiles so that
it can recognise when it's attached to bicycle or motorbike


8) use OSM directly?

we can't rotate the map using OsmGpsMap widget because the labels will
be sideways or upside down, so we need something with vectors that we
can rotate

a) we can get data from overpass api as json

b) we would like to cache the results, which means some kind of
chunking or tiling so that the json for position a is the same as the
json for position b.

c) at coarser zoom levels, we need to query for fewer objects: either 
do it by hand -

- houses
- minor roads
- major roads

or so something smart but complicated like "only return ways that
cover more than 1/16th the length of the tile"

d) I think we will need some kind of server so that multiple users get
the benefit of the caching. If we're going to do that, should it also
do transformation e.g. from lat/long to x/y co-ordinates? We don't
need this bit yet though

3) alternatively we could use mapbox vector tiles, but tbh I'm
struggling to see now that helps. we don't have to transform from
lat/long but instead we have to parse a protobuf, how is that simpler?