diff --git a/docs/docs/features/battery.md b/docs/docs/features/battery.md new file mode 100644 index 00000000..0b4172c2 --- /dev/null +++ b/docs/docs/features/battery.md @@ -0,0 +1,38 @@ +--- +title: Battery Level +sidebar_label: Battery Level +--- + +If your keyboard has a battery sensor, ZMK will report its battery level to the connected bluetooth host and show it on the keyboard's display, if it has one. + +For split keyboards, only the battery level of the central (usually left) side is reported over bluetooth. + +:::note + +Windows may not properly ask the keyboard to notify it of changes in battery level, so the level shown may be out of date. + +::: + +## Adding a Battery Sensor to a Board + +To enable a battery sensor on a new board, add the driver for the sensor to your board's `.dts` file. ZMK provides two drivers for estimating the battery level using its voltage: + +- `zmk,battery-voltage-divider`: Reads the voltage on an analog input pin. +- `zmk,battery-nrf-vddh`: Reads the power supply voltage on a Nordic nRF52's VDDH pin. + +Zephyr also provides some drivers for fuel gauge ICs such as the TI bq274xx series and Maxim MAX17xxx series. If you use a battery sensor that does not have an existing driver, you will need to write a new driver that supports the `SENSOR_CHAN_GAUGE_STATE_OF_CHARGE` sensor channel and contribute it to Zephyr or ZMK. + +Once you have the sensor driver defined, add a `zmk,battery` property to the `chosen` node and set it to reference the sensor node. For example: + +``` +/ { + chosen { + zmk,battery = &vbatt; + }; + + vbatt: vbatt { + compatible = "zmk,battery-nrf-vddh"; + label = "VBATT"; + }; +} +``` diff --git a/docs/sidebars.js b/docs/sidebars.js index cbeceef7..ea66439b 100644 --- a/docs/sidebars.js +++ b/docs/sidebars.js @@ -17,6 +17,7 @@ module.exports = { "features/encoders", "features/underglow", "features/backlight", + "features/battery", "features/beta-testing", ], Behaviors: [