can_sniffer/flip_monitor/README.md

CAN Monitor for Flipper Zero

Dynamic multi-page monitor application for Raspberry Pi 5 via UART.

Features

• Dynamic Page System - Pages are fully controlled by RPi5
• Multiple Page Types:
  • Info - Read-only status display
  • Menu - Selectable action items
  • Confirm - Yes/No confirmation dialogs
• Real-time Updates - Content refreshes every second
• Bidirectional Communication - Send commands back to RPi5
• Result Notifications - Action results displayed as overlay

Default Pages

When connected to the CAN Sniffer system:

Page	Type	Description
CAN Statistics	Info	Frame counts, queue status, per-interface stats
UPS Status	Info	Battery level, voltage, charging state (X120x)
System Info	Info	CPU temperature, power consumption, fan RPM
Actions	Menu	Shutdown, Reboot, Cancel shutdown

Screen Layout

128x64 pixels (Flipper Zero display)

+----------------------------------+
| [1/4] Page Title            (*)  |  <- Header: page indicator, title, connection dot
+----------------------------------+
|                                  |
| Content Line 1                   |  <- Content area: 4-5 lines
| Content Line 2                   |
| Content Line 3                   |
| Content Line 4                   |
|                                  |
+----------------------------------+
| <          Hint Text          >  |  <- Footer: nav arrows, action hint
+----------------------------------+

Controls

Key	Info Page	Menu Page	Confirm Page
Left/Right	Navigate pages	Navigate pages	Navigate pages
Up/Down	-	Select item	Switch Yes/No
OK	-	Execute action	Confirm selection
Back	Disconnect (pg 0) / Prev page	Same	Cancel dialog

Protocol

RPi5 -> Flipper

PAGE:<idx>/<total>|<type>|<title>|<lines>|<actions>|<selected>
ACK:<device>,ip=<ip>
RESULT:<OK|ERROR>|<message>

Examples:

PAGE:0/4|info|CAN Statistics|Total: 12.3K;Processed: 12.1K;Queue: 142||0
PAGE:1/4|info|UPS Status|Bat: 85.2% [====];Voltage: 4.12V;Status: Charging||0
PAGE:2/4|info|System Info|CPU Temp: 52.1C;Power: 4.2W;Fan: 3200 RPM||0
PAGE:3/4|menu|Actions|Shutdown;Reboot;Cancel Shutdown||0
PAGE:3/4|confirm|Confirm Shutdown?|Are you sure?|Yes;No|1
ACK:rpi5,ip=192.168.1.100
RESULT:OK|Shutdown in 1 min

Flipper -> RPi5

INIT:flipper          - Start handshake
STOP:flipper          - Disconnect
CMD:NAV:next          - Next page
CMD:NAV:prev          - Previous page
CMD:SELECT:<index>    - Select menu item
CMD:CONFIRM           - Confirm action
CMD:CANCEL            - Cancel action
CMD:REFRESH           - Request page update

Hardware Connection

Wiring Diagram

Flipper Zero            Raspberry Pi 5
-----------             ---------------
Pin 13 (TX)    ---->    GPIO 15 (RX) - Pin 10
Pin 14 (RX)    <----    GPIO 14 (TX) - Pin 8
Pin 8/11/18 (GND) ----  GND - Pin 6

Note: Cross TX/RX connections (Flipper TX -> RPi RX)

Flipper Zero GPIO Pinout

Pin 13 = TX (USART)
Pin 14 = RX (USART)
Pin 8/11/18 = GND

RPI5 GPIO (using /dev/ttyAMA0)

GPIO 14 = TX (Pin 8)
GPIO 15 = RX (Pin 10)
GND = Pin 6, 9, 14, 20, 25, 30, 34, 39

Building the Application

Prerequisites

1. Clone Flipper Zero firmware:

git clone --recursive https://github.com/DarkFlippers/unleashed-firmware.git
cd unleashed-firmware

2. Copy the flip_monitor folder to applications_user/:

cp -r /path/to/carpibord/flip_monitor applications_user/can_monitor

Build

# Build the FAP
./fbt fap_can_monitor

# Or build all external apps
./fbt fap_dist

The compiled .fap file will be in build/f7-firmware-D/.extapps/can_monitor.fap

Install

Copy the .fap file to your Flipper Zero SD card:

SD Card/apps/GPIO/can_monitor.fap

RPI5 Configuration

1. Enable UART

Add to /boot/firmware/config.txt:

enable_uart=1
dtoverlay=uart0

Disable serial console:

sudo raspi-config
# Interface Options -> Serial Port -> No (login shell) -> Yes (hardware)

Reboot after changes.

2. Install Dependencies

pip install pyserial smbus2 gpiozero

3. Configure CAN Sniffer

Add to can_sniffer/src/config.json:

{
  "flipper": {
    "enabled": true,
    "device": "/dev/ttyAMA0",
    "baudrate": 115200,
    "send_interval": 1.0
  }
}

Or use environment variables:

export CAN_SNIFFER_FLIPPER__ENABLED=true
export CAN_SNIFFER_FLIPPER__DEVICE=/dev/ttyAMA0

4. Run CAN Sniffer

cd can_sniffer/src
python main.py

Adding Custom Pages

On RPi5 side, create a new page class:

from flipper.pages.base import InfoPage

class MyCustomPage(InfoPage):
    def __init__(self):
        super().__init__(
            name="my_page",
            title="My Page",
            icon="custom"
        )

    def get_lines(self) -> list[str]:
        return [
            "Custom line 1",
            "Custom line 2",
            f"Value: {self.get_value()}"
        ]

Register in FlipperHandler:

# In flipper_handler.py
from flipper.pages.my_custom import MyCustomPage

# In _setup_pages():
self._page_manager.register_page(MyCustomPage())

Troubleshooting

No connection

1. Check wiring (TX/RX crossed correctly)
2. Verify UART is enabled on RPI5: ls -la /dev/ttyAMA0
3. Check config: flipper.enabled = true
4. Test UART manually:

# On RPI5
echo "ACK:rpi5,ip=test" > /dev/ttyAMA0

Permission denied on /dev/ttyAMA0

Add user to dialout group:

sudo usermod -a -G dialout $USER
# Then logout and login again

Flipper shows "Waiting for data..."

• Data is sent every 1 second (configurable)
• Connection timeout is 5 seconds
• Check if CAN sniffer is running
• Check UART logs: CAN_SNIFFER_LOGGING__LEVEL=DEBUG python main.py

UPS page shows "not available"

• X120x UPS must be connected via I2C
• Install smbus2: pip install smbus2
• Check I2C: i2cdetect -y 1 (should show device at 0x36)

Version History

• v2.0 - Dynamic page system, bidirectional commands, UPS/System pages
• v1.0 - Basic CAN statistics display

License

MIT License