Configuration (config.json)

m5-grayline reads its settings from /grayline/config.json on the microSD card.

Creating the settings file

Insert a microSD card into the device and turn it on. If /grayline/config.json does not exist, it is created with default values.
Turn the device off and put the microSD card in your computer.
Open /grayline/config.json in a text editor and fill in wifi.ssid and wifi.password. Change other settings, such as your location, as needed.
Put the card back in the device and turn it on.

You can also copy config.example.json to the card as /grayline/config.json and edit it.

Example

{
  "version": 1,
  "wifi": { "ssid": "your-ssid", "password": "your-password" },
  "home": {
    "name": "Tokyo",
    "lat": 35.6895,
    "lon": 139.6917,
    "geoip": true,
    "ipinfo_token": ""
  },
  "map": { "center_lon": 139.6917 },
  "time": {
    "tz_label": "JST",
    "tz_offset_min": 540,
    "ntp": ["ntp.nict.jp", "time.google.com", "pool.ntp.org"],
    "ntp_interval_min": 360
  },
  "display": { "brightness": 160, "dim_brightness": 16, "wake_sec": 30, "day_alt_deg": -6 }
}

Settings

Omitted keys use their default values.

Key	Type	Default	Description
`version`	integer	`1`	Format version of the file. Do not change it.
`wifi.ssid`	string	`""`	Wi-Fi SSID. Use a 2.4 GHz network.
`wifi.password`	string	`""`	Wi-Fi password.
`home.name`	string	`"Home"`	Name of your location, shown on the info screen. Used only when `home.lat` and `home.lon` are set.
`home.lat`	number	none	Latitude in degrees, positive north.
`home.lon`	number	none	Longitude in degrees, positive east.
`home.geoip`	boolean	`true`	Whether to estimate the location with GeoIP (ipinfo.io) when `home.lat` / `home.lon` are not set.
`home.ipinfo_token`	string	`""`	ipinfo.io access token (optional). The free tier works without a token.
`map.center_lon`	number	your longitude	Longitude of the map center in degrees.
`time.tz_label`	string	`"JST"`	Time zone name shown before the local time at the top.
`time.tz_offset_min`	integer	`540`	Offset from UTC in minutes, e.g. `540` for Japan, `330` for India, `-300` for New York (standard time).
`time.ntp`	array of strings	`["ntp.nict.jp", "time.google.com", "pool.ntp.org"]`	NTP servers, up to three.
`time.ntp_interval_min`	integer	`360`	Interval between NTP syncs in minutes. After a failed sync, the device retries every 30 minutes.
`display.brightness`	integer (0-255)	`160`	Backlight level when the screen is bright.
`display.dim_brightness`	integer (0-255)	`16`	Backlight level when the screen is dimmed.
`display.wake_sec`	integer	`30`	How long (seconds) a button press lights up a dimmed screen.
`display.day_alt_deg`	number	`-6`	Sun altitude (degrees) at your location above which it counts as daytime, for the backlight.

How your location is chosen

Your location is chosen in the following order. The info screen shows the source (config, GeoIP or default) at the top right.

home.lat and home.lon, if set.
Otherwise (and if home.geoip is true), an estimate by GeoIP (ipinfo.io) after connecting to Wi-Fi and synchronizing the time. The result is stored on the device and used first at the next startup.
Otherwise, Tokyo (35.6895° N, 139.6917° E).

GeoIP gives an approximate location (often city level) estimated from your global IP address. Depending on your internet provider, it can be far from where you are. For an exact location, set home.lat and home.lon.

GeoIP and privacy

If home.lat and home.lon are not set, the device queries ipinfo.io at startup and at every NTP sync (every 6 hours by default). This sends your global IP address to ipinfo.io.

The device does not contact ipinfo.io if you do either of the following:

Set home.lat and home.lon.
Set home.geoip to false (Tokyo is used if no latitude / longitude is set).

If home.ipinfo_token is set, the token is sent with the request in an HTTP header, not in the URL.