Idea of timelapse with automatic settings

[hhanswurster]

Hey Guys,

i new to programing and have my first project in mind :)

Rasberry pi with light sensor, that automaticly changes my camera settings to a optimal exposure, captures a image and saves it at a hard drive connected to the pi.

First of all, is there something like that allready ? i dont want to reinvent the weel.

my setup hardware setup so far:
Rasberry Pi 3
ADAFRUIT TSL2561 connected via i2c https://www.adafruit.com/product/439
Sony A5100 connected via USB
3 TB USB harddrive for storing the images.

Software:
Rasbian light

gphoto2

gphoto2 --capture-image-and-download --filename "images/%Y_%m_%d_%H_%M_%S.arw"  # capture image rename it and store it...

# these 3 settings can be used to change the exposure :)

gphoto2 --set-config iso=X #values Choice: 2 100 to Choice: 14 1600
gphoto2 --set-config f-Number=X  #values 2.8 to 22
gphoto2 --set-config shutterspeed=X    #values  30s: 300/10  25s: 250/10 1/200s: 1/200 and so on

Pyhton script (thanks ryker1990) that i modified to output the mesured lux:

import smbus
import time

# Get I2C bus
bus = smbus.SMBus(1)

# TSL2561 address, 0x39(57)
# Select control register, 0x00(00) with command register, 0x80(128)
#		0x03(03)	Power ON mode
bus.write_byte_data(0x39, 0x00 | 0x80, 0x03)
# TSL2561 address, 0x39(57)
# Select timing register, 0x01(01) with command register, 0x80(128)
#		0x02(02)	Nominal integration time = 402ms
bus.write_byte_data(0x39, 0x01 | 0x80, 0x02)

time.sleep(0.5)

# Read data back from 0x0C(12) with command register, 0x80(128), 2 bytes
# ch0 LSB, ch0 MSB
data = bus.read_i2c_block_data(0x39, 0x0C | 0x80, 2)

# Read data back from 0x0E(14) with command register, 0x80(128), 2 bytes
# ch1 LSB, ch1 MSB
data1 = bus.read_i2c_block_data(0x39, 0x0E | 0x80, 2)

# Convert the data
ch0 = data[1] * 256 + data[0]
ch1 = data1[1] * 256 + data1[0]

# Output data to screen

print "%d lux" %(ch0 - ch1)

To do (what i think hahaha)
Make a "list" of all camera settings possible from dark to bright.
Measure several brightness levels and manualy adjust the camera settings to that brightness.
Extrapolate the rest?

than write a script:

every 30 minutes:
read lux measurement
look up the correct setting in the list
set the camera to that settings
(wait: needs some time)
capture image, rename it, save it on the harddrive
write a logfile that it worked
start again :D

im a total noob, do you think its possible like that?
what would you do differently ?
any thoughts appreciated :)

Hans