Raspberry Pi HAT design files

I have embarked on a journey to create a Raspberry Pi HAT for a little project of mine and I wanted to share a couple of things that I think may help you speed up your development time in the future. As of 11/5/16 I have tested out the DXF importing it into KiCad and using as the edge cut profile. The blank PCB’s test HATS we had made up fit nicely on the RPi2. As I push further on this journey I’ll continue to post any design files that I feel could help you with future iterations.

I can confirm that this fits onto the rPi3 also.


RPi HAT Files



Edit files on your Raspberry Pi the easy way

For us linux “late-adopters” it can be a daunting task of carrying out a routine file transfer to our Raspberry Pi from our Windows PC. However the learning curve is not so great. There are plenty of easy tools for achieving this feat. If you have not been introduced to Notepad++ then we will give you a quick introduction. We will also educate you on a small plugin inside of Notepad++ that allows you to run a lightweight FTP client. This client is really only suitable for your scripting files or editing configuration files but you will learn the basics of how FTP works and then have the skills to upgrade to a more robust FTP client for moving other files onto the Raspberry Pi.


Prerequisites

  • Install Notepad++ on your windows PC. https://notepad-plus-plus.org/
  • Download Putty. Link Below
  • Ensure your Raspberry Pi is plugged into your network via Ethernet (cat5)
  • Power up your Pi
  • Ensure your LAN has DHCP enabled...most routers will have this set as default.


Finding your RPi IP address

If you already have your raspberry pi on the network and you know its IP address then that is half the battle. Alternatively if you have just finished installing Raspbian and you are not sure what to do from here then do not panic!! Check this article to find your IP address. http://dirtyoptics.com/find-raspberry-pi-ip-address/


Method 1: Notepad++ (My Favourite!)

Navigate your way to: https://notepad-plus-plus.org/ and download the latest release for Notepad++. Install as per any other windows application and run it up. You will notice it looks very similar to the generic windows text editor however it does allow for some syntax highlighting. A handy little editor also if you are just starting to dive into Python and other coding languages.

Once Notepad++ is open, navigate to: Plugins / NppFTP / Show NppFTP Window. (If you do not see NppFTP you may need to go into the plugin manager and install it)

Once you have the NppFTP window open you will need to create an SFTP profile for your RPI. Please note that when SSH is enabled on your Pi it also opens up port 22 for you to utilise SFTP over the SSH connection. (Well thats my understanding anyhow!).

  • Insert Pi IP
  • Port 22
  • Select SFTP
  • Username: pi (If left as default)
  • Password: raspberry (If left as default)

After you have set it up, click close/save. Find and click the connect button in the NppFTP window and connect to the profile you just setup. After a few seconds you should be able to view a “windows like” file tree of your Pi. You can also double click on any text file and edit directly in the Notepad ++ editor. When you click “save” it will automatically upload that file back to the Pi. Particularly useful when editing Python code and you want to run directly on the Pi. This can be dangerous at times, if updating important configuration docs ensure you back them up first.


Method 2: Using SSH/Terminal and 'Nano' Editor

If you are feeling adventurous, and want to use SSH to edit configuration files then strap yourself in. For the ‘un-intiated’, Linux commands differ heavily from the standard Win DOS commands. You will notice some similarities, but for the most part its a bit of a learning curve. We are not going to cover absolutley everything here but the basics for editing files whilst you are in a terminal session. (Accessing you Pi directly)

The first thing you will want to ensure is that your RPI is powered up, Plugged into your network and you know the IP address . Assuming you have installed Raspbian onto your Micro SD and inserted the SD card prior to powering up we can then begin to access the Pi via SSH. (SSH = Secure SHell). This is pretty much a standard way of accessing your Raspberry Pi if you do not have a monitor available. SSH is enabled by default as part of the Raspbian build.

You will now be required to download and open a small terminal program called ‘Putty’ (There are other, but this is the most popular) http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html run the putty.exe from your PC and input the following information.

  • Hostname/IP Addres - Insert your RPI IP
  • Port 22
  • Select SSH

Now that you have logged into your Raspberry Pi via SSH its time to start Nano. Nano is a Linux command line text editor. It is pretty simple to get running and use. It can be run in two different ways.

sudo nano

This will create a blank text entry. The correct syntax to follow is:

sudo nano /path/to/filename

If you use a path that is not valid or it cannot find the file you want to edit, then a blank entry will be created.

If you wanted to edit the Raspberry Pi config file, then the command would look like:

Now that you have accessed the config file with nano, you can go through and make your changes. Use the arrow keys to navigate through the text file, and the usual backspace/enter to move things around.

It would be wise to make a backup file of this configuration first

Once complete, hit CTRL-X to exit, then Y to save. It will overwrite the old file with your new one.



What Next?

  • Download and try winSCP to transfer images and larger files.
  • Setup an FTP server on the Raspberry Pi.
  • Utilise a standalone FTP client to connect to the Raspberry Pi. (Filezilla/cuteFTp etc etc)


32 x 32 LED Matrix setup on RPI2

After building a few LED matrices from LED strip lighting and soldering a ton of connections, I decided to give these pre-fabricated LED matrix modules a shot. After a bit of research it turns out that using only a Raspberry Pi and a fully functional Library from the Legend Henner Zeller, you can accomplish just about anything. The cheap Chinese panels that we sourced are fitted with a HUB75 connector which is easily interfaced with a breadboard and some jumper wires or using the opensource Active-3 board, again designed by Henner. His library can be found here: Rpi-RGB-LED-Matrix Library – https://github.com/hzeller/rpi-rgb-led-matrix


Bill of Materials (BOM)

  • LED Matrix: http://www.aliexpress.com/store/1239156 (P5 32x32 modules with Hub75 are a good starting point.)
  • A Raspberry Pi 2 or 3
  • A breadboard and T-Cobbler RPI 40 pin Breakout (Just to make life easier! You can grab these from Adafruit.)
  • Alternatively build an Active-3 adapter for easier chaining of Matrix Panels. (See hzeller github page for more details.)
  • Some Jumper Wires
  • A sense of adventure.....


Code

Assuming you are semi-proficient with Linux and have installed Raspbian than you can follow along here. Otherwise you first need to setup your RPI and access the terminal/SSH interface. The guide here will get you up and with the “NOOBS” installation for your pi.

Install Henner Zeller’s LED Matrix library onto your Pi:

sudo wget https://github.com/hzeller/rpi-rgb-led-matrix/archive/master.zip

Unzip the Archive:

sudo unzip master.zip

Once unzip completes you should then be able to view the directory and it’s contents:

cd rpi-rgb-led-matrix-master/

You then need to compile the library by running the command:

sudo make

Once compiled, you can run the following command, this will give you an output of all the available switches:

sudo ./led-matrix

This command will output the following for your reference:

$ sudo ./led-matrix
Expected required option -D <demo>
usage: ./led-matrix <options> -D <demo-nr> [optional parameter]
Options:
        -r <rows>     : Panel rows. '16' for 16x32 (1:8 multiplexing),
                        '32' for 32x32 (1:16), '8' for 1:4 multiplexing; Default: 32
        -P <parallel> : For Plus-models or RPi2: parallel chains. 1..3. Default: 1
        -c <chained>  : Daisy-chained boards. Default: 1.
        -L            : 'Large' display, composed out of 4 times 32x32
        -p <pwm-bits> : Bits used for PWM. Something between 1..11
        -l            : Don't do luminance correction (CIE1931)
        -D <demo-nr>  : Always needs to be set
        -d            : run as daemon. Use this when starting in
                        /etc/init.d, but also when running without
                        terminal (e.g. cron).
        -t <seconds>  : Run for these number of seconds, then exit.
                        (if neither -d nor -t are supplied, waits for <RETURN>)
        -b <brightnes>: Sets brightness percent. Default: 100.
        -R <rotation> : Sets the rotation of matrix. Allowed: 0, 90, 180, 270. Default: 0.
Demos, choosen with -D
        0  - some rotating square
        1  - forward scrolling an image (-m <scroll-ms>)
        2  - backward scrolling an image (-m <scroll-ms>)
        3  - test image: a square
        4  - Pulsing color
        5  - Grayscale Block
        6  - Abelian sandpile model (-m <time-step-ms>)
        7  - Conway's game of life (-m <time-step-ms>)
        8  - Langton's ant (-m <time-step-ms>)
        9  - Volume bars (-m <time-step-ms>)
        10 - Evolution of color (-m <time-step-ms>)
        11 - Brightness pulse generator
Example:
        ./led-matrix -t 10 -D 1 runtext.ppm
Scrolls the runtext for 10 seconds

Now its time to get some output onto the panel. If you are running a singular 32×32 panel, you should be able to run the example without issue.

sudo ./led-matrix -t 10 -D 1 runtext.ppm

If your panel is connected correctly and powered up you should see a scrolling image pass through the panel. With the example above it will only last 10 seconds. You can now begin to experiment with the above switches to see what output you can achieve.


Advanced

  • Output RPI GUI to Matrix Panels (Coming Soon!)
  • Output Twitter msg to Matrix Panels (Coming Soon!)
  • Use Pixelpusher Protocol on Matrix (Coming Soon!)


Media