Monitor battery charge in hid keyboard example

[bscdb]

The hid keyboard example includes the battery service. But how does it work? I would like to monitor the battery charge. After I use the voltage divider, to which AIN pin should I connect? Where will the battery charge be displayed?

[Jørgen Holmefjord]

Hi,

Unfortunately, the ble_app_hids_keyboard example does not actually measure the battery voltage. It pass a simulated value to the battery service, see battery_level_update(). The ble_app_proximity example implements actual battery voltage measurement, you can use that as reference. Note that the proximity example use VDD as input. If you use a voltage divider, you should change the input to one of AIN0-AIN7 in parameter to NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE in adc_configure().

Best regards,
Jørgen

[bscdb]

Hi Jorgen,

I have connected a potentiometer to AIN0. I changed the parameter to NRF_SAADC_INPUT_AIN0 in ble_app_proximity example. The values are not getting updated. It is showing 00 constantly under Battery Service tab in nrfconnect even if I refresh/reset. I also tried reducing BATTERY_LEVEL_MEAS_INTERVAL. Ideally ble_bas_battery_level_update() should send updated values. What might be the problem?