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Cronjob Redux

After days of trying to figure this out, I finally got the video to upload via a cronjob.

There were 2 issues.

Issue the first

Finally found the issue. Original script from YouTube developers guidehad this:

CLIENT_SECRETS_FILE = "client_secrets.json"

And then a couple of lines later, this:

% os.path.abspath(os.path.join(os.path.dirname(__file__), CLIENT_SECRETS_FILE))

When crontab would run the script it would run from a path that wasn’t where the CLIENT_SECRETS_FILE file was and so a message would be displayed:

WARNING: Please configure OAuth 2.0

To make this sample run you will need to populate the client_secrets.json file
found at:

  %s

with information from the Developers Console
https://console.developers.google.com/

For more information about the client_secrets.json file format, please visit:
https://developers.google.com/api-client-library/python/guide/aaa_client_secrets

What I needed to do was to update the CLIENT_SECRETS_FILE to be the whole path so that it could always find the file.

A simple change:

CLIENT_SECRETS_FILE  = os.path.abspath(os.path.join(os.path.dirname(__file__), CLIENT_SECRETS_FILE))

Issue the second

When the create_mp4.sh script would run it was reading all of the h264 files from the directory where they lived BUT they were attempting to output the mp4 file to / which it didn’t have permission to write to.

This was failing silently (I’m still not sure how I could have caught the error). Since there was no mp4 file to upload that script was failing (though it was true that the location of the CLIENT_SECRETS_FILE was an issue).

What I needed to do was change the create_mp4.sh file so that when the MP4Box command output the mp4 file to the proper directory. The script went from this:

(echo '#!/bin/sh'; echo -n "MP4Box"; array=($(ls ~/Documents/python_projects/*.h264)); for index in ${!array[@]}; do if [ "$index" -eq 0 ]; then echo -n " -add ${array[index]}"; else echo -n " -cat ${array[index]}"; fi; done; echo -n " hummingbird.mp4") > create_mp4.sh

To this:

(echo '#!/bin/sh'; echo -n "MP4Box"; array=($(ls ~/Documents/python_projects/*.h264)); for index in ${!array[@]}; do if [ "$index" -eq 0 ]; then echo -n " -add ${array[index]}"; else echo -n " -cat ${array[index]}"; fi; done; echo -n " /home/pi/Documents/python_projects/hummingbird.mp4") > /home/pi/Documents/python_projects/create_mp4.sh

The last bit /home/pi/Documents/python_projects/create_mp4.sh may not be neccesary but I’m not taking any chances.

The video posted tonight is the first one that was completely automatic!

Now … if I could just figure out how to automatically fill up my hummingbird feeder.

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Hummingbird Video Capture

I previously wrote about how I placed my Raspberry Pi above my hummingbird feeder and added a camera to it to capture video.

Well, the day has finally come where I’ve been able to put my video of it up on YouTube! It’s totally silly, but it was satisfying getting it out there for everyone to watch and see.

Hummingbird Video Capture: Addendum

The code used to generate the the mp4 file haven’t changed (really). I did do a couple of things to make it a little easier though.

I have 2 scripts that generate the file and then copy it from the pi to my MacBook Pro and the clean up:

Script 1 is called create_script.sh and looks like this:

(echo '#!/bin/sh'; echo -n "MP4Box"; array=($(ls *.h264)); for index in ${!array[@]}; do if [ "$index" -eq 0 ]; then echo -n " -add ${array[index]}"; else echo -n " -cat ${array[index]}"; fi; done; echo -n " hummingbird.mp4") > create_mp4.sh | chmod +x create_mp4.sh

This creates a script called create_mp4.sh and makes it executable.

This script is called by another script called run_script.sh and looks like this:

./create_script.sh
./create_mp4.sh

scp hummingbird.mp4 ryan@192.168.1.209:/Users/ryan/Desktop/

# Next we remove the video files locally

rm *.h264
rm *.mp4

It runs the create_script.sh which creates create_mpr.sh and then runs it.

Then I use the scp command to copy the mp4 file that was just created over to my Mac Book Pro.

As a last bit of housekeeping I clean up the video files.

I’ve added this run_script.sh to a cron job that is scheduled to run every night at midnight.

We’ll see how well it runs tomorrow night!

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ITFDB Demo

Last Wednesday if you would have asked what I had planned for Easter I would have said something like, “Going to hide some eggs for my daughter even though she knows the Easter bunny isn’t real.”

Then suddenly my wife and I were planning on entertaining for 11 family members. My how things change!

Since I was going to have family over, some of whom are Giants fans, I wanted to show them the ITFDB program I have set up with my Pi.

The only problem is that they would be over at 10am and leave by 2pm while the game doesn’t start until 5:37pm (Thanks ESPN).

To help demonstrate the script I wrote a demo script to display a message on the Pi and play the Vin Scully mp3.

The Code was simple enough:

from sense_hat import SenseHat
import os


def main():
    sense = SenseHat()
    message = '#ITFDB!!! The Dodgers will be playing San Francisco at 5:37pm tonight!'
    sense.show_message(message, scroll_speed=0.05)
    os.system("omxplayer -b /home/pi/Documents/python_projects/itfdb/dodger_baseball.mp3")


if __name__ == '__main__':
    main()

But then the question becomes, how can I easily launch the script without futzing with my laptop?

I knew that I could run a shell script for the Workflow app on my iPhone with a single action, so I wrote a simple shell script

python3 ~/Documents/python_projects/itfdb/demo.py

Which was called itfdb_demo.sh

And made it executable

chmod u+x itfdb_demo.sh

Finally, I created a WorkFlow which has only one action Run Script over SSH and added it to my home screen so that with a simple tap I could demo the results.

The WorkFlow looks like this:

Nothing too fancy, but I was able to reliably and easily demonstrate what I had done. And it was pretty freaking cool!

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Setting up ITFDB with a voice

In a previous post I wrote about my Raspberry Pi experiment to have the SenseHat display a scrolling message 10 minutes before game time.

One of the things I have wanted to do since then is have Vin Scully’s voice come from a speaker and say those five magical words, It's time for Dodger Baseball!

I found a clip of Vin on Youtube saying that (and a little more). I wasn’t sure how to get the audio from that YouTube clip though.

After a bit of googling1 I found a command line tool called youtube-dl. The tool allowed me to download the video as an mp4 with one simple command:

youtube-dl https://www.youtube.com/watch?v=4KwFuGtGU6c

Once the mp4 was downloaded I needed to extract the audio from the mp4 file. Fortunately, ffmpeg is a tool for just this type of exercise!

I modified this answer from StackOverflow to meet my needs

ffmpeg -i dodger_baseball.mp4 -ss 00:00:10 -t 00:00:9.0 -q:a 0 -vn -acodec copy dodger_baseball.aac

This got me an aac file, but I was going to need an mp3 to use in my Python script.

Next, I used a modified version of this suggestion to create write my own command

ffmpeg -i dodger_baseball.aac -c:a libmp3lame -ac 2 -b:a 190k dodger_baseball.mp3

I could have probably combined these two steps, but … meh.

OK. Now I have the famous Vin Scully saying the best five words on the planet.

All that’s left to do is update the python script to play it. Using guidance from here I updated my itfdb.py file from this:

if month_diff == 0 and day_diff == 0 and hour_diff == 0 and 0 >= minute_diff >= -10:
   message = '#ITFDB!!! The Dodgers will be playing {} at {}'.format(game.game_opponent, game.game_time)
   sense.show_message(message, scroll_speed=0.05)

To this:

if month_diff == 0 and day_diff == 0 and hour_diff == 0 and 0 >= minute_diff >= -10:
   message = '#ITFDB!!! The Dodgers will be playing {} at {}'.format(game.game_opponent, game.game_time)
   sense.show_message(message, scroll_speed=0.05)
   os.system("omxplayer -b /home/pi/Documents/python_projects/itfdb/dodger_baseball.mp3")

However, what that does is play Vin’s silky smooth voice every minute for 10 minutes before game time. Music to my ears but my daughter was not a fan, and even my wife who LOVES Vin asked me to change it.

One final tweak, and now it only plays at 5 minutes before game time and 1 minute before game time:

if month_diff == 0 and day_diff == 0 and hour_diff == 0 and 0 >= minute_diff >= -10:
   message = '#ITFDB!!! The Dodgers will be playing {} at {}'.format(game.game_opponent, game.game_time)
   sense.show_message(message, scroll_speed=0.05)

if month_diff == 0 and day_diff == 0 and hour_diff == 0 and (minute_diff == -1 or minute_diff == -5):
   os.system("omxplayer -b /home/pi/Documents/python_projects/itfdb/dodger_baseball.mp3")

Now, for the rest of the season, even though Vin isn’t calling the games, I’ll get to hear his voice letting me know, “It’s Time for Dodger Baseball!!!”

  1. Actually, it was an embarrassing amount ↩
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Fixing the Python 3 Problem on my Raspberry Pi

In my last post I indicated that I may need to

reinstalling everything on the Pi and starting from scratch

While speaking about my issues with pip3 and python3. Turns out that the fix was easier than I though. I checked to see what where pip3 and python3 where being executed from by running the which command.

The which pip3 returned /usr/local/bin/pip3 while which python3 returned /usr/local/bin/python3. This is exactly what was causing my problem.

To verify what version of python was running, I checked python3 --version and it returned 3.6.0.

To fix it I just ran these commands to unlink the new, broken versions:

sudo unlink /usr/local/bin/pip3

And

sudo unlink /usr/local/bin/python3

I found this answer on StackOverflow and tweaked it slightly for my needs.

Now, when I run python --version I get 3.4.2 instead of 3.6.0

Unfortunately I didn’t think to run the --version flag on pip before and after the change, and I’m hesitant to do it now as it’s back to working.

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ITFDB!!!

My wife and I love baseball season. Specifically we love the Dodgers and we can’t wait for Spring Training to begin. In fact, today pitchers and catchers report!

I’ve wanted to do something with the Raspberry Pi Sense Hat that I got (since I got it) but I’ve struggled to find anything useful. And then I remembered baseball season and I thought, ‘Hey, what if I wrote something to have the Sense Hat say “#ITFDB” starting 10 minutes before a Dodgers game started?’

And so I did!

The script itself is relatively straight forward. It reads a csv file and checks to see if the current time in California is within 10 minutes of start time of the game. If it is, then it will send a show_message command to the Sense Hat.

I also wrote a cron job to run the script every minute so that I get a beautiful scrolling bit of text every minute before the Dodgers start!

The code can be found on my GitHub page in the itfdb repository. There are 3 files:

  1. Program.py which does the actual running of the script
  2. data_types.py which defines a class used in Program.py
  3. schedule.csv which is the schedule of the games for 2018 as a csv file.

I ran into a couple of issues along the way. First, my development environment on my Mac Book Pro was Python 3.6.4 while the Production Environment on the Raspberry Pi was 3.4. This made it so that the code about time ran locally but not on the server 🤦‍♂️.

It took some playing with the code, but I was finally able to go from this (which worked on 3.6 but not on 3.4):

now = utc_now.astimezone(pytz.timezone("America/Los_Angeles"))
game_date_time = game_date_time.astimezone(pytz.timezone("America/Los_Angeles"))

To this which worked on both:

local_tz = pytz.timezone('America/Los_Angeles')
now = utc_now.astimezone(local_tz)
game_date_time = local_tz.localize(game_date_time)

For both, the game_date_time variable setting was done in a for loop.

Another issue I ran into was being able to display the message for the sense hat on my Mac Book Pro. I wasn’t ever able to because of a package that is missing (RTIMU ) and is apparently only available on Raspbian (the OS on the Pi).

Finally, in my attempts to get the code I wrote locally to work on the Pi I decided to install Python 3.6.0 on the Pi (while 3.4 was installed) and seemed to do nothing but break pip. It looks like I’ll be learning how to uninstall Python 3.4 OR reinstalling everything on the Pi and starting from scratch. Oh well … at least it’s just a Pi and not a real server.

Although, I’m pretty sure I hosed my Linode server a while back and basically did the same thing so maybe it’s just what I do with servers when I’m learning.

One final thing. While sitting in the living room watching DC Legends of Tomorrow the Sense Hat started to display the message. Turns out, I was accounting for the minute, hour, and day but NOT the month. The Dodgers play the Cubs on September 12 at 9:35 (according to the schedule.csv file anyway) and so the conditions to display were met.

I added another condition to make sure it was the right month and now we’re good to go!

Super pumped for this season with the Dodgers!

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Using MP4Box to concatenate many .h264 files into one MP4 file

The general form of the concatenate command for MP4Box is:

MP4Box -add <filename>.ext -cat <filename>.ext output.ext1

When you have more than a couple of output files, you’re going to want to automate that -cat part as much as possible because let’s face it, writing out that statement even more than a couple of times will get really old really fast.

The method below works but I’m sure that there is a better way to do it.

  1. echo out the command you want to run. In this case:

(echo -n "MP4Box "; for i in *.h264; do echo -n " -cat $i"; done; echo -n " hummingbird.mp4") >> com.txt

  1. Edit the file com.txt created in (1) so that you can change the first -cat to -add

vim com.txt

  1. While still in vim editing the com.txt file add the #!/bin/sh to the first line. When finished, exit vim2
  2. Change the mode of the file so it can run

chmod +x com.txt

  1. Run the file:

./com.txt

Why am I doing all of this? I have a Raspberry Pi with a Camera attachment and a motion sensor. I’d like to watch the hummingbirds that come to my hummingbird feeder with it for a day or two and get some sweet video. We’ll see how it goes.

  1. The -add will add the <filename> to the output file while the -cat will add any other files to the output file (all while not overwriting the output file so that the files all get streamed together). ↩
  2. I’m sure there’s an xkcd comic about this, but I just can’t find it! ↩