bluetooth battery service uuid 0x2A19 polling with gatttool

checkbattery

#!/usr/bin/bash

# prints in CSV format for import into visualization tools

hextodec ()
{
  hci_test_device_batterylevel=$((16#$1))
}

if [ -z "$1" ]
  then
    hci_test_device=EC:7E:45:9D:24:C0
  else
    hci_test_device=$1
fi

if [ -z "$2" ]
  then
    hci_polling_interval=60
  else
  hci_polling_interval=$2
fi

echo Polling battery service \(UUID 0x2A19\) from $hci_test_device each $hci_polling_interval seconds >&2

echo Date,Battery Level

while true
do
#read battery level
read_level=$(timeout --preserve-status 10s sudo gatttool -b $hci_test_device -t random --char-read -u 0x2a19 | cut -d ' ' -f 5)
  if [ ! -z "$read_level" ]
    then
      hextodec $read_level
      echo $(date +'%F %T'),$hci_test_device_batterylevel
    else
      # in case for example; connect error: Function not implemented (38)
      echo Problems reading battery level with gatttool >&2
  fi

  sleep $hci_polling_interval
#read HR data for 1 minute
# HR at byte 40-41 (format in https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml)
# Output without filtering:
#    Characteristic value was written successfully
#    Notification handle = 0x000e value: 10 ca 30 01 30 01 30 01 30 01
#  sudo timeout 60s gatttool -b EC:7E:45:9D:24:C0 -t random --char-write-req -a 0xf -n 0100 --listen | awk -v blevel="$BLEVEL" --non-decimal-data '{ printf "%s,%d,%d\n", strftime("%F %H:%M:%S"), "0x",blevel $7 }' | tee -a miobattery.log
done