You can also work with and save BMP format data from an OV2640 or OV7670 camera. Use this format if you need to do image processing within CircuitPython, or if your camera doesn't have a JPEG mode.
Make the following connections for the SD card breakout:
- IO18 to CLK
- IO14 to DI
- IO17 to DO
- IO12 to CS
- GND to GND
- 5V to 5V
While the demo runs, it will show a live image on the LCD. When you hold the REC button, it will save the picture as a BMP image to the inserted SD card. Note that because the REC button is only polled when the screen is not updating, you have to hold it, not just quickly press it.
# SPDX-FileCopyrightText: 2017 Scott Shawcroft, written for Adafruit Industries
# SPDX-FileCopyrightText: Copyright (c) 2021 Jeff Epler for Adafruit Industries
#
# SPDX-License-Identifier: Unlicense
"""
The Kaluga development kit comes in two versions (v1.2 and v1.3); this demo is
tested on v1.3.
The audio board must be mounted between the Kaluga and the LCD, it provides the
I2C pull-ups(!)
The v1.3 development kit's LCD can have one of two chips, the ili9341 or
st7789. Furthermore, there are at least 2 ILI9341 variants, one of which needs
rotation=90! This demo is for the ili9341. If the display is garbled, try adding
rotation=90, or try modifying it to use ST7799.
This example also requires an SD card breakout wired as follows:
* IO18: SD Clock Input
* IO17: SD Serial Output (MISO)
* IO14: SD Serial Input (MOSI)
* IO12: SD Chip Select
Insert a CircuitPython-compatible SD card before powering on the Kaluga.
Press the "Record" button on the audio daughterboard to take a photo in BMP format.
"""
import os
import struct
import analogio
import board
import busdisplay
import busio
import displayio
import fourwire
import sdcardio
import storage
import ulab.numpy as np
import adafruit_ov2640
# Nominal voltages of several of the buttons on the audio daughterboard
V_MODE = 1.98
V_RECORD = 2.41
a = analogio.AnalogIn(board.IO6)
# Release any resources currently in use for the displays
displayio.release_displays()
spi = busio.SPI(MOSI=board.LCD_MOSI, clock=board.LCD_CLK)
display_bus = fourwire.FourWire(
spi,
command=board.LCD_D_C,
chip_select=board.LCD_CS,
reset=board.LCD_RST,
baudrate=80_000_000,
)
_INIT_SEQUENCE = (
b"\x01\x80\x80" # Software reset then delay 0x80 (128ms)
b"\xef\x03\x03\x80\x02"
b"\xcf\x03\x00\xc1\x30"
b"\xed\x04\x64\x03\x12\x81"
b"\xe8\x03\x85\x00\x78"
b"\xcb\x05\x39\x2c\x00\x34\x02"
b"\xf7\x01\x20"
b"\xea\x02\x00\x00"
b"\xc0\x01\x23" # Power control VRH[5:0]
b"\xc1\x01\x10" # Power control SAP[2:0];BT[3:0]
b"\xc5\x02\x3e\x28" # VCM control
b"\xc7\x01\x86" # VCM control2
b"\x36\x01\x90" # Memory Access Control
b"\x37\x01\x00" # Vertical scroll zero
b"\x3a\x01\x55" # COLMOD: Pixel Format Set
b"\xb1\x02\x00\x18" # Frame Rate Control (In Normal Mode/Full Colors)
b"\xb6\x03\x08\x82\x27" # Display Function Control
b"\xf2\x01\x00" # 3Gamma Function Disable
b"\x26\x01\x01" # Gamma curve selected
b"\xe0\x0f\x0f\x31\x2b\x0c\x0e\x08\x4e\xf1\x37\x07\x10\x03\x0e\x09\x00" # Set Gamma
b"\xe1\x0f\x00\x0e\x14\x03\x11\x07\x31\xc1\x48\x08\x0f\x0c\x31\x36\x0f" # Set Gamma
b"\x11\x80\x78" # Exit Sleep then delay 0x78 (120ms)
b"\x29\x80\x78" # Display on then delay 0x78 (120ms)
)
display = busdisplay.BusDisplay(
display_bus, _INIT_SEQUENCE, width=320, height=240, auto_refresh=False
)
bus = busio.I2C(scl=board.CAMERA_SIOC, sda=board.CAMERA_SIOD)
cam = adafruit_ov2640.OV2640(
bus,
data_pins=board.CAMERA_DATA,
clock=board.CAMERA_PCLK,
vsync=board.CAMERA_VSYNC,
href=board.CAMERA_HREF,
mclk=board.CAMERA_XCLK,
mclk_frequency=20_000_000,
size=adafruit_ov2640.OV2640_SIZE_QVGA,
)
cam.flip_x = False
cam.flip_y = False
cam.test_pattern = False
g = displayio.Group(scale=1)
bitmap = displayio.Bitmap(320, 240, 65536)
tg = displayio.TileGrid(
bitmap,
pixel_shader=displayio.ColorConverter(input_colorspace=displayio.Colorspace.RGB565_SWAPPED),
)
g.append(tg)
display.root_group = g
sd_spi = busio.SPI(clock=board.IO18, MOSI=board.IO14, MISO=board.IO17)
sd_cs = board.IO12
sdcard = sdcardio.SDCard(sd_spi, sd_cs)
vfs = storage.VfsFat(sdcard)
storage.mount(vfs, "/sd")
def exists(filename):
try:
os.stat(filename)
return True
except OSError:
return False
_image_counter = 0
def open_next_image(extension="jpg"):
global _image_counter # noqa: PLW0603
while True:
filename = f"/sd/img{_image_counter:04d}.{extension}"
_image_counter += 1
if exists(filename):
continue
print("#", filename)
return open(filename, "wb")
### These routines are for writing BMP files in the RGB565 or BGR565 formats.
_BI_BITFIELDS = 3
_bitmask_rgb565 = (0xF800, 0x7E0, 0x1F)
_bitmask_bgr565 = (0x1F, 0x7E0, 0xF800)
def write_header(output_file, width, height, masks):
def put_word(value):
output_file.write(struct.pack("<H", value))
def put_dword(value):
output_file.write(struct.pack("<I", value))
def put_long(value):
output_file.write(struct.pack("<i", value))
def put_padding(length):
output_file.write(b"\0" * length)
filesize = 14 + 108 + height * width * 2
# BMP header
output_file.write(b"BM")
put_dword(filesize)
put_word(0) # Creator 1
put_word(0) # Creator 2
put_dword(14 + 108) # Offset of bitmap data
# DIB header (BITMAPV4HEADER)
put_dword(108) # sizeof(BITMAPV4HEADER)
put_long(width)
put_long(-height)
put_word(1) # number of color planes (must be 1)
put_word(16) # number of bits per pixel
put_dword(_BI_BITFIELDS) # "compression"
put_dword(2 * width * height) # size of raw bitmap data
put_long(11811) # 72dpi -> pixels/meter
put_long(11811) # 72dpi -> pixels/meter
put_dword(0) # palette size
put_dword(0) # important color count
put_dword(masks[0]) # red mask
put_dword(masks[1]) # green mask
put_dword(masks[2]) # blue mask
put_dword(0) # alpha mask
put_dword(0) # CS Type
put_padding(3 * 3 * 4) # CIEXYZ infrmation
put_dword(144179) # 2.2 gamma red
put_dword(144179) # 2.2 gamma green
put_dword(144179) # 2.2 gamma blue
def capture_image_bmp(the_bitmap):
with open_next_image("bmp") as f:
swapped = np.frombuffer(the_bitmap, dtype=np.uint16)
swapped.byteswap(inplace=True)
write_header(f, the_bitmap.width, the_bitmap.height, _bitmask_rgb565)
f.write(swapped)
display.auto_refresh = False
old_record_pressed = True
while True:
a_voltage = a.value * a.reference_voltage / 65535
cam.capture(bitmap)
bitmap.dirty()
record_pressed = abs(a_voltage - V_RECORD) < 0.05
display.refresh(minimum_frames_per_second=0)
if record_pressed and not old_record_pressed:
capture_image_bmp(bitmap)
old_record_pressed = record_pressed
Page last edited January 22, 2025
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