openmv 1.0.7

OpenMV Camera Protocol V2 - Python library and CLI

OpenMV Python

Python library and CLI for communicating with OpenMV cameras.

Installation

pip install openmv

CLI Usage

Examples

# Basic usage - stream video from camera
openmv --port /dev/ttyACM0

# Run a custom script
openmv --port /dev/ttyACM0 --script my_script.py

# Adjust display scale (default is 4x)
openmv --port /dev/ttyACM0 --scale 5

# Run throughput benchmark
openmv --port /dev/ttyACM0 --bench

# Load firmware symbols for profiler function names
openmv --port /dev/ttyACM0 --firmware build/firmware.elf

# Quiet mode (suppress script output)
openmv --port /dev/ttyACM0 --quiet

# Debug mode (verbose logging)
openmv --port /dev/ttyACM0 --debug

# Preview a custom data channel
openmv --port /dev/ttyACM0 --channel ticks

Options

Option	Default	Description
--port PORT	/dev/ttyACM0	Serial port
--script FILE	None	MicroPython script file to execute
--scale N	4	Display scaling factor
--poll MS	4	Poll rate in milliseconds
--bench	False	Run throughput benchmark mode
--raw	False	Enable raw streaming mode
--timeout SEC	1.0	Protocol timeout in seconds
--baudrate N	921600	Serial baudrate
--firmware FILE	None	Firmware ELF file for profiler symbol resolution
--channel NAME	None	Custom data channel to poll and print
--quiet	False	Suppress script output text
--debug	False	Enable debug logging

Protocol Options

Option	Default	Description
--crc BOOL	true	Enable CRC validation
--seq BOOL	true	Enable sequence number validation
--ack BOOL	true	Enable packet acknowledgment
--events BOOL	true	Enable event notifications
--max-retry N	3	Maximum number of retries
--max-payload N	4096	Maximum payload size in bytes
--drop-rate N	0.0	Packet drop simulation rate (0.0-1.0, for testing)

Keyboard Controls

Key	Action
ESC	Exit
P	Cycle profiler overlay (Off → Performance → Events)
M	Toggle profiler mode (Inclusive ↔ Exclusive)
R	Reset profiler counters

Library Usage

from openmv import Camera

script = """
import csi, time

csi0 = csi.CSI()
csi0.reset()
csi0.pixformat(csi.RGB565)
csi0.framesize(csi.QVGA)
clock = time.clock()
while True:
    clock.tick()
    img = csi0.snapshot()
    print(clock.fps(), "FPS")
"""

# Connect to camera
with Camera('/dev/ttyACM0') as camera:
    # Stop running script (if any)
    camera.stop()

    # Execute script and enable streaming
    camera.exec(script)
    camera.streaming(True)

    # Read frames and output
    while True:
        if frame := camera.read_frame():
            print(f"Frame: {frame['width']}x{frame['height']}")

        if text := camera.read_stdout():
            print(text, end='')

Custom Channels

Custom channels allow bidirectional data exchange between the camera and host.

Camera-side script (MicroPython):

import time
import protocol

class TicksChannel:
    def size(self):
        return 10

    def read(self, offset, size):
        return f'{time.ticks_ms():010d}'

    def poll(self):
        return True

protocol.register(name='ticks', backend=TicksChannel())

Host-side (Python):

from openmv import Camera

with Camera('/dev/ttyACM0') as camera:
    camera.exec(script)

    while True:
        # Check if channel has data
        if camera.has_channel('ticks'):
            size = camera.channel_size('ticks')
            if size > 0:
                data = camera.channel_read('ticks', size)
                print(f"Ticks: {data.decode()}")

Quick Reference

Camera

from openmv import Camera

Camera(
    port,               # Serial port (e.g., '/dev/ttyACM0')
    baudrate=921600,    # Serial baudrate
    crc=True,           # Enable CRC validation
    seq=True,           # Enable sequence number validation
    ack=True,           # Enable packet acknowledgment
    events=True,        # Enable event notifications
    timeout=1.0,        # Protocol timeout in seconds
    max_retry=3,        # Maximum retries
    max_payload=4096,   # Maximum payload size
    drop_rate=0.0,      # Packet drop simulation (testing only)
)

Methods

Method	Description
connect() / disconnect()	Manage connection
is_connected()	Check connection status
exec(script)	Execute a MicroPython script
stop()	Stop the running script
streaming(enable, raw=False, resolution=None)	Enable/disable video streaming
read_frame()	Read video frame → {width, height, format, depth, data, raw_size}
read_stdout()	Read script output text
read_status()	Poll channel status → {channel_name: bool, ...}
has_channel(name)	Check if channel exists
channel_read(name, size=None)	Read from custom channel
channel_write(name, data)	Write to custom channel
channel_size(name)	Get available data size
version()	Get firmware, protocol, and bootloader versions
system_info()	Get camera system information
host_stats() / device_stats()	Get protocol statistics

Profiler Methods (if available)

Method	Description
read_profile()	Read profiler data
profiler_mode(exclusive)	Set inclusive/exclusive mode
profiler_reset(config=None)	Reset profiler counters
profiler_event(counter_num, event_id)	Configure event counter

Exceptions

Exception	Description
OMVException	Base protocol exception
TimeoutException	Timeout during communication
ChecksumException	CRC validation failure
SequenceException	Sequence number mismatch

API documentation

Full API documentation: docs/api.md

Requirements

• Python 3.8+
• pyserial >= 3.5
• numpy >= 1.20.0
• pygame >= 2.0.0
• pyelftools

License

MIT License - Copyright (c) 2025 OpenMV, LLC.