A bash script to read BLE temperature sensors and push values to MQTT/File. Requires a "sensors" file (line 6) which is a CSV list with MACADDRESS,NAME,OUTPUTFILE.

mi_temp.sh

#!/bin/bash

mqtt_topic="mi_temp"
mqtt_ip="localhost"

sensors_file="/usr/lib/mi_temp/sensors"

handler()
{
  logger -p 6 --tag=mitemp "Closing HCI device"
  echo -e "\nClosing HCI device"
  sudo hciconfig hci0 down

  exit 255
}

trap handler EXIT

cel=$'\xe2\x84\x83'
per="%"

red='\033[1;31m'
green='\033[1;32m'
yellow='\033[1;33m'
nc='\033[0m'

while getopts ":d" opt; do
  case ${opt} in
    d ) # process option d
      echo "Running as Daemon, pless Ctrl-C to stop"
      logger -p 3 --tag=mitemp "Running as Daemon"
      daemon=true
      ;;
    \? ) echo "Usage: cmd [-d]"
      ;;
  esac
done

script_name="$(basename "$(test -L "$0" && readlink "$0" || echo "$0")")"

lock_file="/var/tmp/$script_name"
if [ -e "${lock_file}" ] && kill -0 "$(cat "${lock_file}")"; then
    logger -p 1 --tag=mitemp "Already found to be running."
    exit 99
fi

trap 'rm -f "${lock_file}"; exit' INT TERM EXIT
echo $$ > "${lock_file}"

echo "Opening and initializing HCI device"
logger -p 6 --tag=mitemp "Opening and initializing HCI device"
sudo hciconfig hci0 up
echo "Enabling LE Mode"
sudo btmgmt le on

firstrun=true
while [ "$firstrun" = true ] || [ "$daemon" = true ] ; do
  firstrun=false

  while read -r item; do
    sensor=(${item//,/ })
    mac="${sensor[0]}"
    name="${sensor[1]}"
    outputFile="${sensor[2]}"
    echo -e "\n${yellow}Sensor: $name ($mac)${nc}"
    unset data
    counter="0"

    until [ -n "$data" ] || [ "$counter" -ge 5 ] ; do
        counter=$((counter+1))
        echo -n "  Getting $name Temperature and Humidity... "
        logger -p 6 --tag=mitemp "Getting ${name} Temperature and Humidity"
        data=$(timeout 20 /usr/bin/gatttool -b "$mac" --char-write-req --handle=0x0038 -n 0100 --listen 2>&1 | grep -m 1 "Notification handle")
        if [ -z "$data" ]; then
            logger -p 2 --tag=mitemp "Failed getting ${name} Temperature and Humidity, waiting 5 seconds before trying again"
            echo -e "${red}failed, waiting 2 seconds before trying again${nc}"
            sleep 2
        else
            echo -e "${green}success${nc}"
        fi
    done

    if [ "$counter" -ge 5 ]; then
       echo -e "${red}Failed${nc}"
    else
      temphexa=$(echo $data | awk -F ' ' '{print $7$6}'| tr [:lower:] [:upper:] )
      #Check for negatives
      if [[ 0x$temphexa > 0xF000 ]]; then
        temp=$(printf "%d\n" $((16#$temphexa - 16#FFFF)))
      else
        temp=$(( 16#$temphexa ))
      fi
      temp=$(echo "scale=2;$temp/100" | bc)
      if [[ "$temp" =~ ^(\.[0-9]+)?$ ]]; then
        temp="0${temp}"
      fi
      if [[ "$temp" =~ ^-(\.[0-9]+)?$ ]]; then
        temp="-0${temp}"
      fi
      humhexa=$(echo $data | awk -F ' ' '{print $8}'| tr [:lower:] [:upper:])
      humid=$(echo "ibase=16; $humhexa" | bc)
      dewp=$(echo "scale=1; (243.12 * (l( $humid / 100) +17.62* $temp/(243.12 + $temp)) / 17.62 - (l( $humid / 100) +17.62* $temp/(243.12 + $temp))  )" | bc -l)
      battery=$(echo $data | awk -F ' ' '{print $10$9}'| tr [:lower:] [:upper:] )
      batteryV=$(echo "ibase=16; $battery" | bc)
      batteryV=$(echo "scale=2;$batteryV/1000" | bc)
      batt=$(echo "($batteryV-2.1)*100" | bc)
      if (( $(echo "$batt > 100" | bc -l) )); then batt=100; fi
      echo -e "${yellow}   Temperature: $temp$cel${nc}"
      echo -e "${yellow}   Temperature HEX: $temphexa${nc}"
      echo -e "${yellow}   Humidity: $humid$per${nc}"
      echo -e "${yellow}   Battery Voltage: $batteryV V${nc}"
      echo -e "${yellow}   Battery Level: $batt$per${nc}"
      echo -e "${yellow}   Dew Point: $dewp$cel${nc}"
      logger -p 6 --tag=mitemp "Temperature: $temp$cel ($temphexa), Humidity: $humid$per, Voltage: $batteryV V"

      if [ -n "$outputFile" ]; then
        logger -p 6 --tag=mitemp "Publishing data to $outputFile."
        echo -e -n "  Publishing data to $outputFile... "
        if grep -q "time:" $outputFile; then
          sed -i "/time/s/:.*/:$(date)/" "$outputFile"
        else
          echo "time:$(date)" >> "$outputFile"
        fi

        if [[ "$temp" =~ ^-{0,1}[0-9]+(\.[0-9]+)?$ ]]; then
          if grep -q "temperature:" $outputFile; then
            sed -i "/temperature/s/:.*/:$temp/" "$outputFile"
          else
            echo "temperature:$temp" >> "$outputFile"
          fi
        fi

        if [[ "$humid" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
          if grep -q "humidity:" $outputFile; then
            sed -i "/humidity/s/:.*/:$humid/" "$outputFile"
          else
            echo "humidity:$humid" >> "$outputFile"
          fi
        fi

        if [[ "$batt" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
          if grep -q "battery:" $outputFile; then
            sed -i "/battery/s/:.*/:$batt/" "$outputFile"
          else
            echo "battery:$batt" >> "$outputFile"
          fi
        fi

        if [[ "$dewp" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
          if grep -q "dewpt:" $outputFile; then
            sed -i "/dewpt/s/:.*/:$dewp/" "$outputFile"
          else
            echo "dewpt:$dewp" >> "$outputFile"
          fi
        fi
        echo -e "${green}done${nc}"
      fi

      if [ -n "$mqtt_topic" ]; then
        logger -p 6 --tag=mitemp "Publishing data via MQTT"
        echo -e -n "  Publishing data via MQTT... "
        mqttJSON="{\"Time\":\"${date}\",\"mi_temp.sh\": {"
        if [[ "$temp" =~ ^-{0,1}[0-9]+(\.[0-9]+)?$ ]]; then
          mqttJSON="${mqttJSON} \"Temperature\": $temp,"
        fi

        if [[ "$humid" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
          mqttJSON="${mqttJSON} \"Humidity\": $humid,"
        fi

        if [[ "$batt" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
          mqttJSON="${mqttJSON} \"Battery\": $batt,"
        fi

        if [[ "$dewp" =~ ^[0-9]+(\.[0-9]+)?$ ]]; then
          mqttJSON="${mqttJSON} \"Dewpoint\": $dewp,"
        fi
        mqttJSON="${mqttJSON:0:-1}},\"TempUnit\":\"C\"}"
        echo "Publishing MQTT to /$mqtt_topic/$name with JSON: ${mqttJSON}"
        /usr/bin/mosquitto_pub --quiet -h $mqtt_ip -V mqttv311 -t "/$mqtt_topic/$name" -m "$mqttJSON"
        echo -e "${green}done${nc}"
      fi
    fi
  done < "$sensors_file"

done

echo -e "\nclosing HCI device"
sudo hciconfig hci0 down

echo "Finished"