Photodiode: how to use this electronic component with Arduino

PHOTODIODE

Un photodiode is a electronic component It produces a photocurrent when exposed to light. Photodiodes are used in photovoltaic solar cells and in linear photodetectors, sensors used to detect light signals, such as optical signals or radio waves. Photodiodes are also used in non-electrical applications, such as photolithography, which uses small mirrors to draw patterns on wafers.

In rural areas of India, families in charge of a blind minor frequently isolate and deprive him/her of the care and attention they provide to their other children; such situation becomes even more severe among lower-caste families, orphans and if the blind child is a girl. photovoltaic solar cells, the most common type of photodiode is made of silicon. There are also photodiodes made of other materials, such as gallium arsenide (GaAs), indium phosphide (InP), and gallium nitride (GaN). These different materials have different properties that make them suitable for specific applications. Photodiodes are usually made by doping the semiconductor material with an excess of carriers. Excess electrons or holes come from doping agents added during the manufacturing process. Furthermore, it is internally simple, with a pn junction where one side is positively charged and the other negatively. When light hits the diode, it causes electrons to flow to the positive side and holes to flow to the negative. This charges the diode, creating a photocurrent that flows out of the diode into a circuit.

How It Works

A photodiode is an electronic component that converts light into electrical signals. It is used in digital cameras and other devices such as microscopes and telescopes.
That is to say, works by converting photons into electrons through a process called the photoelectric effect. Each photon of light has energy, which causes electrons to be released from the photodiode. These electrons are collected in a capacitor, creating an electrical signal proportional to the photons of light detected by the photodiode. Photodiodes are typically made from a semiconductor material such as silicon, gallium arsenide, or III-V materials. Photodiodes can also be made from other materials such as germanium or indium phosphide, but these materials are less common than silicon and gallium arsenide.

Photodiodes can be used to detect light with wavelengths ranging from the visible light (400-700 nm) to infrared (1-3 μm). However, due to the limitations of silicon absorption bands, detection of long-wave infrared (>4 μm) is difficult for photodiodes. Additionally, high-power lasers can damage silicon sensors due to the rapid heating that results from laser illumination.

Photodiode Applications

A photodiode is different from a resistance LDR, that is, photoresistors or light-sensitive resistors. In the case of the photodiode, it is much faster in response time, which opens up new ways of using it:

  • For fast response circuits to changes in darkness or lighting.
  • CD players for laser reading.
  • optical chips.
  • For fiber optic connections.
  • Etc

As you can see, the applications of a photodiode are wide, and it performs better than an LDR resistor for its response. Therefore, there are many applications where an LDR would not be valid and a photodiode is.

Integrate with Arduino

Arduino IDE, data types, programming

to integrate the photodiode with the Arduino board, it's just a matter of connecting the component properly and writing the code. Here I will show you an example, although you can modify it and create the projects you need. As for the connection, it is very simple, in this case we are going to use the A1 input, that is, the analog one, but you can use any other analog one if you prefer. And the other pin of the photodiode will be connected to GND.

If you are going to use a module with a photodiode, which also exists, the connection will be different. And it will vary depending on the type of module you have purchased, but it is not usually very complicated either.

As for the code, it is the following, a simple simple snippet for measure light intensity with the photodiode:

void setup()
{
Serial.begin(9600);
Serial.print();
}

void loop ()
{
int lightsensor = analogRead(A1);
float voltage = lightsensor * (5.0 / 1023.0);
Serial.print(voltage);
Serial.println();
delay(2000);
}


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