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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.