DIY Arduino 入射式测光表

A Lightmeter/Flashmeter for photographers, based on Arduino. Components:

  • Arduino NANO v.3
  • BH1750 light sensor
  • SSD1306 128*96 OLED SPI Display
  • Buttons

Thanks @morozgrafix for creating schematic diagram for this device. The lightmeter based on Arduino as a main controller and BH1750 as a metering cell.

Information is displayed on SSD1306 OLED display. The device is powered by 2 AAA batteries. Functions list:

  • Ambient light metering
  • Flash light metering
  • ND filter correction
  • Aperture priority
  • Shutter speed priority
  • ISO range 8 - 4 000 000
  • Aperture range 1.0 - 3251
  • Shutter speed range 1/10000 - 133 sec
  • ND Filter range ND2 - ND8192
  • Displaying amount of light in Lux.
  • Displaying exposure value, EV
  • Recalculating exposure pair while one of the parameter changing
  • Battery information
  • Power 2xAAA LR03 batteries

Detailed information on my site: https://www.pominchuk.com/lightmeter/

DIY测光表测光模式相当于相机内中央平均测光。在大多数拍摄情况下中央平均测光是一种非常实用的测光模式,在拍摄人像旅游照等对于中央亮度起到决定性作用的拍摄场景时,应用广泛。

所需元件

1.  Arduino nano
2.  BH1750光强度模块
3.  0.96寸 7针SPI接口oled屏幕(SSD1306)

源码&&焊接

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#include <SPI.h>
#include <Wire.h>
#include <Adafruit\_GFX.h>
#include <Adafruit\_SSD1306.h>
#include <BH1750.h>
#include <EEPROM.h>
#include <avr/sleep.h>
#define SCREEN\_WIDTH 128 // OLED display width, in pixels
#define SCREEN\_HEIGHT 64 // OLED display height, in pixels

// Declaration for SSD1306 display connected using software SPI (default case):
#define OLED\_DC 11
#define OLED\_CS 12
#define OLED\_CLK 8 //10
#define OLED\_MOSI 9 //9
#define OLED\_RESET 10 //13
Adafruit\_SSD1306 display(SCREEN\_WIDTH, SCREEN\_HEIGHT,
OLED\_MOSI, OLED\_CLK, OLED\_DC, OLED\_RESET, OLED\_CS);

BH1750 lightMeter;

#define DomeMultiplier 2.17 // Multiplier when using a white translucid Dome covering the lightmeter
#define MeteringButtonPin 2 // Metering button pin
#define PlusButtonPin 3 // Plus button pin
#define MinusButtonPin 4 // Minus button pin
#define ModeButtonPin 5 // Mode button pin
#define MenuButtonPin 6 // ISO button pin
#define MeteringModeButtonPin 7 // Metering Mode (Ambient / Flash)
//#define PowerButtonPin 2

#define MaxISOIndex 57
#define MaxApertureIndex 70
#define MaxTimeIndex 80
#define MaxNDIndex 13
#define MaxFlashMeteringTime 5000 // ms

float lux;
boolean Overflow = 0; // Sensor got Saturated and Display "Overflow"
float ISOND;
boolean ISOmode = 0;
boolean NDmode = 0;

boolean PlusButtonState; // "+" button state
boolean MinusButtonState; // "-" button state
boolean MeteringButtonState; // Metering button state
boolean ModeButtonState; // Mode button state
boolean MenuButtonState; // ISO button state
boolean MeteringModeButtonState; // Metering mode button state (Ambient / Flash)

boolean ISOMenu = false;
boolean NDMenu = false;
boolean mainScreen = false;

// EEPROM for memory recording
#define ISOIndexAddr 1
#define apertureIndexAddr 2
#define modeIndexAddr 3
#define T\_expIndexAddr 4
#define meteringModeAddr 5
#define ndIndexAddr 6

#define defaultApertureIndex 12
#define defaultISOIndex 11
#define defaultModeIndex 0
#define defaultT\_expIndex 19

uint8\_t ISOIndex = EEPROM.read(ISOIndexAddr);
uint8\_t apertureIndex = EEPROM.read(apertureIndexAddr);
uint8\_t T\_expIndex = EEPROM.read(T\_expIndexAddr);
uint8\_t modeIndex = EEPROM.read(modeIndexAddr);
uint8\_t meteringMode = EEPROM.read(meteringModeAddr);
uint8\_t ndIndex = EEPROM.read(ndIndexAddr);

int battVolts;
#define batteryInterval 10000
double lastBatteryTime = 0;

#include "lightmeter.h"

void setup() {
pinMode(PlusButtonPin, INPUT\_PULLUP);
pinMode(MinusButtonPin, INPUT\_PULLUP);
pinMode(MeteringButtonPin, INPUT\_PULLUP);
pinMode(ModeButtonPin, INPUT\_PULLUP);
pinMode(MenuButtonPin, INPUT\_PULLUP);
pinMode(MeteringModeButtonPin, INPUT\_PULLUP);

//Serial.begin(115200);

battVolts = getBandgap(); //Determins what actual Vcc is, (X 100), based on known bandgap voltage

Wire.begin();
lightMeter.begin(BH1750::ONE\_TIME\_HIGH\_RES\_MODE\_2);
//lightMeter.begin(BH1750::ONE\_TIME\_LOW\_RES\_MODE); // for low resolution but 16ms light measurement time.

display.begin(SSD1306\_SWITCHCAPVCC, 0x3D);
display.setTextColor(WHITE);
display.clearDisplay();

// IF NO MEMORY WAS RECORDED BEFORE, START WITH THIS VALUES otherwise it will read "255"
if (apertureIndex > MaxApertureIndex) {
apertureIndex = defaultApertureIndex;
}

if (ISOIndex > MaxISOIndex) {
ISOIndex = defaultISOIndex;
}

if (T\_expIndex > MaxTimeIndex) {
T\_expIndex = defaultT\_expIndex;
}

if (modeIndex < 0 modeIndex > 1) {
// Aperture priority. Calculating shutter speed.
modeIndex = 0;
}

if (meteringMode > 1) {
meteringMode = 0;
}

if (ndIndex > MaxNDIndex) {
ndIndex = 0;
}

lux = getLux();
refresh();
}

void loop() {
if (millis() >= lastBatteryTime + batteryInterval) {
lastBatteryTime = millis();
battVolts = getBandgap();
}

readButtons();

menu();

if (MeteringButtonState == 0) {
// Save setting if Metering button pressed.
SaveSettings();

lux = 0;
refresh();

if (meteringMode == 0) {
// Ambient light meter mode.
lightMeter.configure(BH1750::ONE\_TIME\_HIGH\_RES\_MODE\_2);

lux = getLux();

if (Overflow == 1) {
delay(10);
getLux();
}

refresh();
delay(200);
} else if (meteringMode == 1) {
// Flash light metering
lightMeter.configure(BH1750::CONTINUOUS\_LOW\_RES\_MODE);

unsigned long startTime = millis();
uint16\_t currentLux = 0;
lux = 0;

while (true) {
// check max flash metering time
if (startTime + MaxFlashMeteringTime < millis()) { break; } currentLux = getLux(); delay(16); if (currentLux > lux) {
lux = currentLux;
}
}

refresh();
}
}
}

运行库

  • Adafruit_Circuit_Playground
  • Adafruit_Sensor
  • Adafruit_SSD1306
  • Adafruit-GFX-Library
  • BH1750

2020.11.23

立个flag 2022-02-03

  • 重新设计PCB
作者

椰椰雪球

发布于

2020-11-23

更新于

2022-02-04

许可协议

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