Programs to map values for ping times into color values and meter setting

generate_pings.sh

#!/bin/bash
# pings specified host once, greps out latency
# usage:
#   generate_pings.sh <host> <ping_time_limit>
host=$1
ping_scale_limit=$2 
ping_time=$(ping -c1 $host | grep from | cut -d '=' -f 4 |  cut -d " " -f 1) 
printf "%3.0f 0 %3.0F 0 255\n" $ping_time $ping_scale_limit

map.awk

# map values for ping times into color values and meter setting

# usage 
# echo x in_min in_max out_min out_max | awk -f this program
# outputs the scaled x value and r, g, b values


BEGIN{
    # RGB color table -- roughly a spectrum
    colors[1]="255 0 0"
    colors[2]="255 128 0"
    colors[3]="255 255 0"
    colors[4]="128 255 0"
    colors[5]="0 255 0"
    colors[6]="0 255 128"
    colors[7]="0 255 255"
    colors[8]="0 128 255"
    colors[9]="0 0 255"
    colors[10]="127 0 255"
    colors[11]="255 0 255"
    colors[12]="255 0 127"
}

{
    x = $1
    x = constrain( x, $2, $3 )
    
    result = map( x, $2, $3, $4, $5 )
    if( result < 0 ) result = 0 

    color_index = int(map(result, 0, $5, 12, 1))
    printf "%d %s\n", result, colors[color_index]
} 

function constrain( in_x, min_x, max_x ) {
    if( in_x < min_x ) in_x = min_x
    if( in_x > max_x ) in_x = max_x 
    return in_x
}

# implement Arduino's map function in awk
# based  on https://www.arduino.cc/reference/en/language/functions/math/map/
#long map(long x, long in_min, long in_max, long out_min, long out_max) {
#  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
#}
function map(x, in_min, in_max, out_min, out_max) {
    return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min
}

ping_wrapper.sh

#!/bin/bash
# setup for use with cron (1 minute intervals)
. ~jerry/.profile
/home/jerry/generate_pings.sh yahoo.com 500 | awk -f /home/jerry/map.awk | /home/jerry/rgb_lights.sh

rgb_lights.sh

#!/bin/bash
# usage:
#    rgb_lights.sh <meter> <red> <green> <blue>
# where value is between 0 and 255

read meter red green blue 

# pins for rgb led use with pigs command
meter_pin=23
red_pin=17
green_pin=27
blue_pin=22

#echo $meter_pin $meter
pigs p $meter_pin $meter
pigs p $red_pin $red
pigs p $green_pin $green
pigs p $blue_pin $blue

printf '%(%Y-%m-%d %H:%M:%S)T' -1 
printf ",%d\n" $meter 

The pigs command comes from the pipgpio library:.