So you’ve decided to leave the SIGNAL '18 kiosk on your Hackpack v4…

Awesome! That’s why we built this Raspberry Pi-based handheld for you.

Under the skin of the Hackpack v4, there’s a full computer with monitor and keyboard support. Once you break out of the SIGNAL kiosk you’ll initially be underwhelmed by how similar to your desktop it is (it even has a spreadsheet program!).

That’ll pass quickly. The true power of the Hackpack is in the platform. Let’s talk about how you break out, and what to do when you do.

Break Out of the Hackpack v4

There are three main paths to break out of the Hackpack v4 (and a somewhat hidden one you can hit through the webview).

Break Out with our New Firmware

Now that SIGNAL 2018 is over, we've created a firmware which boots to desktop.

1. Download our Kiosk-free firmware image and decompress.
2. Using Etcher, burn it to a 8GB or larger MicroSD Card (further details here).
3. Insert the MicroSD Card into your Hackpack and power on.
4. Let the Hackpack reboot once, then follow the below instructions to set up Wi-Fi.
5. Build something amazing.

The username is pi and password is twiliox2018.

Break Out with a Keyboard

The simplest way to break out of the kiosk is to use a keyboard and (probably) a Micro USB to USB dongle (such as this). Simply attach a keyboard and mouse… and when inside the SIGNAL 18 kiosk hold ALT F4 to quit to desktop.

Break Out with a Serial Cable

The white header on top of the board is a Seeed Grove connector with 3.3v UART signals aboard. Looking at the screen, from left to right the signals are Rx, Tx, 3.3V, Gnd.

Use a 3.3V UART to USB adapter such as this with Grove breakout cables such as these to connect to the Pi. The username to use is pi and password twiliox2018.

Once logged in, you have a full shell. Run sudo pkill -f kiosk.py to quit the SIGNAL kiosk and get to the desktop.

Staying On the Lam

If you use one of the latter two methods to break out you probably don’t want to go back. We can help you with that too!

In the directory /home/pi/firmware/bin there is a file boot.sh which bootstraps the drivers and launches the kiosk. Remove or comment out this line and the next time you reboot, you’ll still taste freedom.

Connecting to Wi-Fi

Hackpack v4s come by default with Wi-Fi credentials for SIGNAL 2018. There are two ways to connect to a new network.

• Keyboard and Mouse: From the Desktop, right click the Wireless icon on the task bar. Select your network and enter the password.
• Command Line: Two options:
  • Run the command sudo raspi-config and walk through the steps to connect.
  • Edit the file /etc/wpa_supplicant/wpa_supplicant.conf, using your own network credentials in place of the network blocks inside.

Wi-Fi is persistent; any changes you make will automatically remain between boots.

Playing with the Drivers

Once you exit the kiosk, all of the functionality of your board is intact. There are three drivers running on top of a base Raspbian installation.

LED Driver

The LED driver onboard spins in a while loop waiting for input on a UNIX socket, /dev/lightsocket. It expects packets 100 bytes long, padded with 0 and delimited by a vertical bar, e.g.:

00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000|Command

Here are the commands accepted by the LED driver:

• CLR - Clear the light sequence
• PRT - Print the light sequence
• SHW - Run the light sequence
• R1,G1,B1,R2,G2,B2,R3,G3,B3,R4,G4,B4,R5,G5,B5,DELAY
  • R#,G#,B#: An integer between 0 and 255. 0 is OFF, 255 is FULL ON.
    • 1 through 5: LEFTmost LED to RIGHTmost LED
  • DELAY: Integer, time to pause on colors, in milliseconds.

Seriously, though—you don’t need any integer over 120 or so. We mean it - the LEDs are extremely bright!

The easiest way to use the lightserver might be to use our Python light client. There we’ve defined 39 LED patterns which we use(d) during SIGNAL. Call the light client on the command line with:

python /home/pi/firmware/drivers/leds/light_client/lightclient.py -h

Input Driver

The input driver controls three major components on the Hackpack:

1. The resistive touchscreen on the 2.8” display
2. The analog joystick
3. The 7 buttons

While it’s a complex piece of code, it should operate mostly as a black box. Other than some sensitivity thresholds (which we encourage you to customize), the most interesting thing we built is an input mode switch.

The input driver listens to a socket at /dev/hackpack_input_driver. That socket allows you to flip between MOUSE mode and ARROW mode.

In MOUSE mode, the joystick operates with a mouse. The START button is a left click and the SELECT button is a right click.

In ARROW mode, the joystick acts like the arrow keys on the keyboard. The START button is an enter key and the SELECT button is a space.

Also onboard are 5 additional buttons:

• A, B, X, Y (act as keypresses)
• Escape/Power (acts as Escape key)

If you hold down ESCAPE for 3 seconds, the Hackpack will power down safely.

Display Driver

The Hackpack v4 runs the fbcp_ili9341 display driver by juj. We didn’t make any modifications other than to the default cmake command and the config.h file.

cmake -DILI9341=ON -DGPIO_TFT_DATA_CONTROL=22 -DGPIO_TFT_RESET_PIN=27 -DGPIO_TFT_BACKLIGHT=23 -DSPI_BUS_CLOCK_DIVISOR=12 -DSTATISTICS=0 -DBACKLIGHT_CONTROL=ON -DDMA_TX_CHANNEL=11 -DDMA_RX_CHANNEL=4 -DDISPLAY_BREAK_ASPECT_RATIO_WHEN_SCALING=ON

If you do recompile, we suggest dropping it in the place of the current binary and restarting.

Have Fun!

The driving goal of the Hackpack—and the drivers—is to provide you with a base for your next project well after the tents at SIGNAL have been taken down. We hope that you continue to use it long after the show and turn it into your own unique creation.

With the SIGNAL kiosk app, we’re showing you our take on one way to use the Hackpack. We know you’re going to take it further—and we can’t wait to see what you do with it.