# IoT Decimal/Hexadecimal 8x8 LED Matrix Drawing Board

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This project is a follow-up project of my previous Instructable called IoT RPi LED Message Board. I am a facilitator for a local Girls Who Code club and I wanted a simple yet fun tool to teach students on how to convert from bitmap/binary to decimal and hexadecimal.

Please follow Steps 1 and 2 on IoT RPi LED Message Board to configure RPi. We'll be using the same setup as my previous project except for the new ZeroMQ server code that uses a different max7219 function to draw pixels column by column (or row by row if you rotate the LED matrix 90 degree clockwise.)

## Step 1: ZeroMQ Server

Run it as root:

`sudo python max7219_set_byte.py`

Now the ZeroMQ server is ready to receive row values in decimal from the web page.

If you want to shutdown the server, just do Control-C to exit the server screen.

## Step 2: Web Page

Untar it:

`tar -xzvf led_pixel.tar.gz `

This creates following files:

`pixel.py                             (main program)./templates/interstitial.html        (page template)./templates/send_pixel.html          (page template)./static/img/led_matrix_bitmap.jpg   (jpg used in page template)`

You may have to change permissions on these files to allow read and execute (only for *.py) by Apache.

Now, enter the URL for pixel.py on your browser and make sure the web page comes up (see photo).

You could test it by entering decimal values of a drawing. For example, if you want to draw the space invader shown on the web page, enter:

`24     (....because first row's bitmap is 00011000 and this translates to 24 in decimal)`
`60`
`126`
`219`
`255`
`36`
`90`
```165
```

(Note: If you need help with binary to decimal conversion, google it or see http://www.wikihow.com/Convert-from-Binary-to-Deci...)

Click on Submit. If everything is setup correctly and ZeroMQ server is running, this should display that space invader on the LED matrix.

`18`
`3C`
`7E`
`DB`
`FF`
`24`
`5A`
`A5`

Click on Submit. This should display the same space invader on the LED matrix. If you need a tutorial on binary to hex conversion, google it or see http://www.wikihow.com/Convert-Binary-to-Hexadecim...

Now come up with your own cool 8x8 drawing but you must learn how to convert bitmap/binary to decimal or hexadecimal!

## Recommendations

• ### Internet of Things Class

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