Arduino Uno Pinout Guide. In our last two posts, we focused on the software aspects of the Arduino. We saw that Arduino boards are programmed using a language derived from C and C in Arduino's Integrated Development Environment (IDE) and learned a few basic debugging methods.In this post, we'll be taking a closer look at the Arduino hardware, and more specifically, the Arduino Uno pinout. The Arduino NANO is a smaller, breadboard-friendlier version of the Arduino UNO. This Arduino NANO Pinout diagram reference is a handy guide for using this board: Arduino NANO Pinout Description The Arduino NANO pins, similar to the UNO, is divided into digital pins, analog pins and power pins. Arduino Nano Pinout Description. Taking this pin-out diagram below as reference, we shall discuss all the functionalities of each and every pin. Arduino Nano Pinout. We can infer from the image that Arduino Nano got 36 pins in total. We will see all the pins section wise as well as a detailed format at last. Arduino Nano Pin Layout! D1/TX (1) (30) VIN D0/RX (2) (29) GND RESET (3) (28) RESET.

Created on: 4 January 2018

How to use the photo resistor sensor module from the 37 in 1 sensor kit for Arduino from Geekcreit, Elegoo, Elektor and others. In some kits the module may be called an LDR (Light Dependent Resistor), photocell, or be written 'photoresistor'.

Arduino Nano V3 Pinout

This tutorial shows the basic use and testing of the photo resistor sensor module with Arduino. Arduino sketches show how to read the photo resistor sensor when connected to an analog input pin.

Note that there are two different pinouts for the photo resistor sensor module, depending on which kit it is from. See the photo resistor sensor module pinout for more details.

The image below shows the photo resistor sensor module used in this tutorial.

Geekcreit Photo Resistor Sensor Module

Photo Resistor Sensor Module Circuit

Important:

Before continuing, refer to the photo resistor sensor module pinout to determine the configuration of your photo resistor sensor. There are two different photo resistor sensors.

The photo resistor module can be wired to the Arduino using the 10k resistor on the module as shown in the circuit diagrams below.

Geekcreit Photo Resistor Sensor Module Circuit

Before building the circuit, it is recommended to check your module with a multimeter to make sure which pins the 10k resistor (R1) on the module is connected to.

Photo Resistor Module Connections to Arduino:

Arduino Nano I2c Pinout

Pin 1 (S) of the module connects to the Arduino 5V pin.
Pin 2 of the module connects to the Arduino GND pin.
Pin 3 (-) of the module connects to an Arduino analog input pin. Arduino analog input A0 is used in the sketches below, but can be changed.

Geekcreit Photo Resistor Sensor Module Arduino Circuit

Alternate Photo Resistor Sensor Module Circuit

If your photo resistor module is configured with the 10k resistor connected between pins 1 and 2 of the module, then use the following circuit.

Photo Resistor Module Connections to Arduino:

Pin 1 (S) of the module connects to an Arduino analog input pin. Arduino analog input A0 is used in the sketches below, but can be changed.
Pin 2 of the module connects to the Arduino GND pin.
Pin 3 (-) of the module connects to the Arduino 5V pin.

Alternate Photo Resistor Sensor Module Arduino Circuit

Photo Resistor Sensor Module Arduino Sketches

Three different sketches can be found below that all use the photo resistor sensor module. All three sketches are used with the above circuits.

Photo Resistor Analog Value Arduino Sketch

The following sketch reads the analog value from the photo resistor module and sends it out of the serial/USB port of the Arduino. Use the Serial Monitor from the Arduino IDE to see the analog value.

Open the Serial Monitor window by clicking the icon at the top right of the Arduino IDE as shown in the image below and marked with a red dot.

How to Open the Arduino Serial Monitor Window

When the serial monitor window is open, make sure that the baud setting is 9600 baud as marked by the red dot at the bottom right of the above image. Values from pin A0 should be seen scrolling in the serial monitor window as shown in the image.

Light Activated LED Arduino Sketch

When the value read from the photo resistor sensor module goes below the threshold value, i.e. it becomes dark, the Arduino on-board LED is switched on. The LED is switched off when the analog value from the sensor goes above the threshold value.

A threshold value can be selected by using the previous sketch to determine the analog value at the desired light level when the LED should be triggered. The value assigned to the threshold variable at the top of the sketch can then be set to the new value.

When the photoresistor sensor is covered, blocking most light, the on-board LED should switch on. When enough light hits the sensor, the LED should switch off.

Analog Input Arduino IDE Example Sketch

One of the example programs, called AnalogInput that comes with the Arduino IDE, can be used with the circuit in this tutorial. Find the sketch in the Arduino IDE under File → Examples → 03.Analog → AnalogInput.

Also see the Arduino Analog Input tutorial on the Arduino website that uses this sketch with a potentiometer and the above circuit from this tutorial.

The AnalogInput sketch flashes the on-board LED faster or slower, depending on the light intensity on the photoresistor module.

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