GOES-17 receiver and gif animator

I shared a gif on reddit demonstrating the results of my GOES-17 project, phase 1. Some people asked for more information about my setup, so here we go.

Hardware Setup

• I followed This blog as a guide to setup my receiver. Flawless instructions!
• Everything is mounted on my roof on a tripod.
• I put my raspberry pi, SDR, and filter in a project box from Amazon and sealed the holes for the wires with roofing caulk. Ziptied it to the tripod.
• I ran 100ft 16ga wire from a variable power supply to the roof. I used some lever wire nuts to split the power from the 16ga to the raspberry pi and the filter inside the project box.

Image Processing

Additional to the steps using the goes tools from the guide to get images from the receiver in the first place, I put together a small script that runs via cron to send images to a cloud server.

• I have a droplet running on Digital Ocean to host the images.
• Install ImageMagick on the raspberry pi and the remote server.
• I run this script every minute via cron to check if there is a newly received image, and if so then compress the images (so it uploads faster), upload them to the cloud, and convert to a gif on the remote server:

#!/bin/bash

COUNT=48
WIDTH=640
USER=REMOTE_HOST_USERNAME
HOST=REMOTE_IP_HERE

# sort the GOES-17 fullcolor images by date and get the latest file
a=$(find /home/pi/goes17/fd/fc/ -type f -exec stat --format '%Y :%y %n %s' "{}" \; | grep jpg | sort -nr | cut -d: -f2- | head -n 1| awk '{print $4}')
# get the last recorded latest filename
b=$(cat /home/pi/goes17/fd/fc/latest.filename.txt)
echo "latest $a vs $b"
# if the last recorded is different from the newest received
if [[ "$a" != "$b" ]]
then
		# record the newest received to the latest filename record and upload
        echo $a > /home/pi/goes17/fd/fc/latest.filename.txt
        echo "uploading..."
        scp $a $USER@$HOST:/var/www/goes/_latest.jpg
        ssh $USER@$HOST cp /var/www/goes/_latest.jpg /var/www/goes/latest.jpg

		# sort the files by date from newest to oldest. Get the last 48 images.
		# We expect to get one every 30 minutes, so this would ideally be 24 hours worth, but sometimes we
		# lose an image. So check the timestamps and get fewer than 48 if some time slots were missed
        anim=$(find /home/pi/goes17/fd/fc/ -type f -exec stat --format '%Y :%y %n %s' "{}" \; | grep jpg | sort -nr | cut -d: -f2- | head -n $COUNT | awk '{print $4}' | tac | perl -lne 'print;/(\d{8})T(\d{4})/; if (!$a) { $d1 = $1; $a = $2; } else { $d2 = $1; $b = $2; exit if $d2 > $d1 && $b >= $a ; }' | xargs)

        # make the local working directory just in case. only necessary the first time but let's be sure.
        mkdir /tmp/goes_anim

        # remove old temp files
        rm /tmp/goes_anim/*

        # copy new animation source files
        cp $anim /tmp/goes_anim/

        # use ImageMagick to resize the animation source files
        echo "resizing"
        cd /tmp/goes_anim && mogrify -resize $WIDTH *.jpg

        # remove the old animation source files on the remote host
        ssh $USER@$HOST rm /var/www/goes/anim/*
        
        # copy new source animation files to remote
        scp /tmp/goes_anim/* $USER@$HOST:/var/www/goes/anim/

        # convert remote sources to gif using ImageMagick
        ssh $USER@$HOST 'convert -delay 10 -loop 0 /var/www/goes/anim/*.jpg /var/www/goes/24hr.gif' &
fi

• this could clearly be made better if I only upload the latest image and delete the previous oldest if it’s older than 24 hours. I’ll leave that as an exercise for the reader.

FIN

The results are awesome!

• gif
• image