SCRUM Monkey

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Introduction: SCRUM Monkey

In my workplace, we have a daily scrum meeting at exactly 13:40. Regardless to that, I have a small monkey toy which makes some monkey noises and blinks while pressing its right ear. I decided to turn it into an alarm by connecting it to my Raspberry Pi.

This monkey has it's own power supply (3.3v) so I had to use a darlington transistor (TIP120/121/122 family) for switching. Just take a look at the photos and scheme, it's a very simple circuit. To control the monkey with the RPi, I wrote a small and simple Python script which activated the alarm at 13:40 by using the good old Linux crontab program.

Here's a link to the video on Youtube:
https://www.youtube.com/watch?v=T6SphTKMWPM

Step 1: Components & Scheme



• TIP120 (or 121, 122)
• 1K ohm resistor


Step 2: Python Script

Step 3: Crontab

On the Linux shell, type:

$ crontab -e

In the editor that has just been opened, type:

40 13 * * * /usr/bin/python /home/scrum_monkey.py

The format of crontab is:
1 2 3 4 5 command

where:
1 - Minute (0 - 59)
2 - Hour (0 - 23)
3 - Day of month (1 - 31)
4 - Month (1 - 12)
5 - Day of week (0 - 7)

There are some special characters you can use instead of the numeric values. For example asterisk (*) in hour means every hour. Read the manual. By the way, I've noticed that the format is a bit diffetent, depends on the Linux distro.

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    4 Comments

    I love that you could deploy this across different locations if your scrum teams are remote working and everyone gets screamed at at once.

    Love it!

    SCRUM can normally get boring but I love the playful element of the Monkey as a way of making it fun.

    isn't the crontab command wrong? shouldn't it be

    * * * 13 40 (whatever the rest of the command is)

    1 reply

    Actually, when I edited it the first time, I took the format from my CentOS 6.5 machine and that format is just like you say. It didn't work and I didn't understand what's wrong. Than I found the other format and it's working.
    I guess some Linux distros use this format and other distros use the other one.
    Anyway, on Debian Wheezy (my RPi distro), it's the format I wrote.