A bash script to change the color of a Philips Wiz WiFi light bulb throughout the day

color-clock.sh

#!/bin/bash

IP=192.168.86.24
PORT=38899

while :
do
    HOURS=$(date +"%-H")
    MINUTES=$(date +"%-M")
    MINUTES=$(($HOURS * 60 + $MINUTES))
    HUE=$(($MINUTES * 360 / 1440))

    case $(($HUE / 60)) in
        0)
            R=255
            G=$((255 * ($HUE - 0) / 60))
            B=0
            ;;
        1)
            R=$((255 * (120 - $HUE) / 60))
            G=255
            B=0
            ;;
        2)
            R=0
            G=255
            B=$((255 * ($HUE - 120) / 60))
            ;;
        3)
            R=0
            G=$((255 * (240 - $HUE) / 60))
            B=255
            ;;
        4)
            R=$((255 * ($HUE - 240) / 60))
            G=0
            B=255
            ;;
        5)
            R=255
            G=0
            B=$((255 * (360 - $HUE) / 60))
            ;;
        *)
            R=255
            G=255
            B=255
            ;;
    esac
    printf '{"method":"setPilot","params":{"r":%d,"g":%d,"b":%d}}' $R $G $B > /dev/udp/$IP/$PORT
    printf "It's $MINUTES minutes past midnight for a hue of $HUE degrees and an RGB value of #%02X%02X%02X\n" $R $G $B
    sleep 240
done