#?MAVlink?OpticalFlow?script.
#
#?This?script?sends?out?OpticalFlow?detections?using?the?MAVlink?protocol?to
#?an?ArduPilot/PixHawk?controller?for?position?control?using?your?OpenMV?Cam.
#
#?P4?=?TXD

import?image?math?pyb?sensor?struct?time

#?Parameters?#################################################################

uart_baudrate?=?115200

MAV_system_id?=?1
MAV_component_id?=?0x54
MAV_OPTICAL_FLOW_confidence_threshold?=?0.1??#?Below?0.1?or?so?（YMMV）?and?the?results?are?just?noise.

##############################################################################

#?LED?control
led?=?pyb.LED（2）?#?Red?LED?=?1?Green?LED?=?2?Blue?LED?=?3?IR?LEDs?=?4.
led_state?=?0

def?update_led（）:
????global?led_state
????led_state?=?led_state?+?1
????if?led_state?==?10:
????????led.on（）
????elif?led_state?>=?20:
????????led.off（）
????????led_state?=?0

#?link?Setup

uart?=?pyb.UART（3?uart_baudrate?timeout_char?=?1000）

#?Helper?Stuff

packet_sequence?=?0

def?checksum（data?extra）:?#?https://github.com/mavlink/c_library_v1/blob/master/checksum.h
????output?=?0xFFFF
????for?i?in?range（len（data））:
????????tmp?=?data[i]?^?（output?&?0xFF）
????????tmp?=?（tmp?^?（tmp?<????????output?=?（（output?>>?8）?^?（tmp?<>?4））?&?0xFFFF
????tmp?=?extra?^?（output?&?0xFF）
????tmp?=?（tmp?^?（tmp?<????output?=?（（output?>>?8）?^?（tmp?<>?4））?&?0xFFFF
????return?output

MAV_OPTICAL_FLOW_message_id?=?100
MAV_OPTICAL_FLOW_id?=?0?#?unused
MAV_OPTICAL_FLOW_extra_crc?=?175

#?http://mavlink.org/messages/common#OPTICAL_FLOW
#?https://github.com/mavlink/c_library_v1/blob/master/common/mavlink_msg_optical_flow.h
def?send_optical_flow_packet（x?y?c）:
????global?packet_sequence
????temp?=?struct.pack（“???????????????????????int（x）
????