light-on-new-thing.sh

watcher.sh

#!/bin/bash
echo 18 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio18/direction
echo 1 > /sys/class/gpio/gpio18/value

LAST=`curl -s https://api-davidtaylor-staging.foursquare.com/latest.id`
echo 0 > /sys/class/gpio/gpio18/value
sleep 2
echo 1 > /sys/class/gpio/gpio18/value
echo "waiting..."
killfile=/opt/watcher.kill

if [ -f "$killfile" ]; then
  rm "$killfile"
fi

while [ ! -f "$killfile" ]; do
  ID=`curl -s https://api-davidtaylor-staging.foursquare.com/latest.id`

  if [ -z "$ID" ]; do
    ID="$LAST"
  fi

  if [ "$ID" != "$LAST" ]; then
    echo "changed: $LAST -> $ID"
    echo 0 > /sys/class/gpio/gpio18/value
    sleep 10
    echo 1 > /sys/class/gpio/gpio18/value
  fi

  LAST="$ID"
  sleep 1
done

echo "exiting due to kill file"

rm "$killfile"