Tuesday, 7 December 2021

SOME VGA & 2 MEGA PIXEL MEMORIES

Standard

Memory Is NEED To be SPECIAL but Not CAMERA

[I Was on a Trekking and waiting my group to reach me . Silent click by one of Group Member]


[Just a Pose which is very friendly with me. Please Do not Judge! I am not a Model!]



[Obviously not a Film Pose . I was Admiring the beauty of NATURE. Didn't know when a friend clicked it silently.]


[Clicked by Friend while I was trying to take his Pic. I know I was Dammed Serious because Semester Result released After 1 Hour]


[Iconic Pose for Me Always. Taught by a friend.]


[Selfie by Self when Front cam was not Exist in this world.]

Thursday, 1 July 2021

ESP32

Standard
 


ESP32

What is ESP32:

ESP32 is a system on a chip(SoC) that integrates the following features:

  • Wi-Fi (2.4 GHz band):
  • Bluetooth
  • Dual high performance cores
  • Ultra Low Power co-processor
  • Multiple peripherals

Powered by 40 nm technology, ESP32 provides a robust, highly integrated platform, which helps meet the continuous demands for efficient power usage, compact design, security, high performance, and reliability.

Espressif provides basic hardware and software resources to help application developers realize their ideas using the ESP32 series hardware. The software development framework by Espressif is intended for development of Internet-of-Things (IoT) applications with Wi-Fi, Bluetooth, power management and several other system features.

Features:

Following block diagram explains all inbuilt features of  ESP32
Ultra­Low­Power Solution ESP32 is designed for mobile, wearable electronics, and Internet-of-Things (IoT) applications. It features all the state-of-the-art characteristics of low-power chips, including fine-grained clock gating, multiple power modes, and dynamic power scaling. For instance, in a low-power IoT sensor hub application scenario, ESP32 is woken up periodically and only when a specified condition is detected. Low-duty cycle is used to minimize the amount of energy that the chip expends. The output of the power amplifier is also adjustable, thus contributing to an optimal trade-off between communication range, data rate and power consumption.

Wi­Fi Key Features :
  • 802.11 b/g/n
  • 802.11 n (2.4 GHz), up to 150 Mbps
  • WMM 
  • TX/RX A-MPDU, RX A-MSDU 
  • Defragmentation 
  • Automatic Beacon monitoring (hardware TSF) 
  • 4 × virtual Wi-Fi interfaces 
  • Simultaneous support for Infrastructure Station, SoftAP, and Promiscuous modes 
  • Antenna diversity

BT Key Features :
  • Compliant with Bluetooth v4.2 BR/EDR and BLE specifications 
  • Class-1, class-2 and class-3 transmitter without external power amplifier 
  • Enhanced Power Control 
  • +12 dBm transmitting power 
  • NZIF receiver with –94 dBm BLE sensitivity 
  • Adaptive Frequency Hopping (AFH) 
  • Standard HCI based on SDIO/SPI/UART 
  • High-speed UART HCI, up to 4 Mbps 
  • Bluetooth 4.2 BR/EDR BLE dual mode controller 
  • Synchronous Connection-Oriented/Extended (SCO/eSCO) 
  • CVSD and SBC for audio codec 
  • Bluetooth Piconet and Scatternet 
  • Multi-connections in Classic BT and BLE 
  • Simultaneous advertising and scanning
CPU and Memory :
  • Xtensa® single-/dual-core 32-bit LX6 microprocessor(s), up to 600 MIPS (200 MIPS for ESP32-S0WD/ESP32-U4WDH, 400 MIPS for ESP32-D2WD) 
  • 448 KB ROM 
  • 520 KB SRAM 
  • 16 KB SRAM in RTC 
  • QSPI supports multiple flash/SRAM chips
Clocks and Timers :

  • Internal 8 MHz oscillator with calibration 
  • Internal RC oscillator with calibration 
  • External 2 MHz ~ 60 MHz crystal oscillator (40 MHz only for Wi-Fi/BT functionality)
  • External 32 kHz crystal oscillator for RTC with calibration 
  • Two timer groups, including 2 × 64-bit timers and 1 × main watchdog in each group 
  • One RTC timer
  • RTC watchdog

Advanced Peripheral Interfaces :
  • 34 × programmable GPIOs 
  • 12-bit SAR ADC up to 18 channels 
  • 2 × 8-bit DAC 
  • 10 × touch sensors 
  • 4 × SPI 
  • 2 × I²S 
  • 2 × I²C 
  • 3 × UART 
  • 1 host (SD/eMMC/SDIO) 
  • 1 slave (SDIO/SPI) 
  • Ethernet MAC interface with dedicated DMA and IEEE 1588 support 
  • Two-Wire Automotive Interface (TWAI®, compatible with ISO11898-1) 
  • IR (TX/RX) 
  • Motor PWM 
  • LED PWM up to 16 channels 
  • Hall sensor

Secure boot :
  • Flash encryption 
  • 1024-bit OTP, up to 768-bit for customers 
  • Cryptographic hardware acceleration: – AES – Hash (SHA-2) 
  • RSA – ECC – Random Number Generator (RNG)


Applications (A Non­exhaustive List) :

  • Generic Low-power IoT Sensor Hub 
  • Generic Low-power IoT Data Loggers 
  • Cameras for Video Streaming
  • Over-the-top (OTT) Devices 
  • Speech Recognition
  • Image Recognition 
  • Mesh Network 
  • Home Automation – Light control – Smart plugs – Smart door locks 
  • Smart Building – Smart lighting – Energy monitoring 
  • Industrial Automation – Industrial wireless control – Industrial robotics 
  • Smart Agriculture – Smart greenhouses – Smart irrigation – Agriculture robotics 
  • Audio Applications – Internet music players – Live streaming devices – Internet radio players – Audio headsets 
  • Health Care Applications – Health monitoring – Baby monitors 
  • Wi-Fi-enabled Toys – Remote control toys – Proximity sensing toys – Educational toys 
  • Wearable Electronics – Smart watches – Smart bracelets 
  • Retail & Catering Applications – POS machines – Service robots

Types & Specifications:

The ESP32 series of chips includes follwing variants...

  • ESP32-D0WD-V3 
  • ESP32-D0WDQ6-V3 
  • ESP32-D0WD
  • ESP32-D0WDQ6 
  • ESP32-D2WD E
  • SP32-S0WD 
  • ESP32-U4WDH
ESP32 WROOM PINOUT:






For More Updates...Please Follow: 

For ESp32 based Development Board Variants and market price:

Firmware and Types:

ESP32 Supports many firmwares and Programming languages. It does matter for a developpper to choose right firmware before developming any product. Right firmware and supported libraries are the main building blocks for developing  a good product.

Following table represents the Firmware Types Programming Language support with Links..

Programming Language Supports:

  1. Embeddded C,C++
  2. Python
    For More Reference:

IDEs:

1. VS Code


 

2. Arduino IDE


RTOS:



Power Consumption and Modes:

 ESP32 offers 5 configurable power modes. As per the power requirement, the chip can switch between different power modes. The modes are:

  • Active Mode
  • Modem Sleep Mode
  • Light Sleep Mode

  • Deep Sleep Mode
  • Hibernation Mode




Sample Codes, Experiments and Example:

LED Blinking Code:

/*
 * ON Board LED GPIO 2
 */

#define LED 2

void setup() {
  // Set pin mode
  pinMode(LED,OUTPUT);
}

void loop() {
  delay(500);
  digitalWrite(LED,HIGH);
  delay(500);
  digitalWrite(LED,LOW);
}

O/P:



Wifi Station Code:


#include <WiFi.h>
#include <WebServer.h>

/* Put your SSID & Password */
const char* ssid = "ESP32";  // Enter SSID here
const char* password = "12345678";  //Enter Password here

/* Put IP Address details */
IPAddress local_ip(192,168,1,1);
IPAddress gateway(192,168,1,1);
IPAddress subnet(255,255,255,0);

WebServer server(80);

uint8_t LED1pin = 4;
bool LED1status = LOW;

uint8_t LED2pin = 5;
bool LED2status = LOW;

void setup() {
  Serial.begin(115200);
  pinMode(LED1pin, OUTPUT);
  pinMode(LED2pin, OUTPUT);

  WiFi.softAP(ssid, password);
  WiFi.softAPConfig(local_ip, gateway, subnet);
  delay(100);
  
  server.on("/", handle_OnConnect);
  server.on("/led1on", handle_led1on);
  server.on("/led1off", handle_led1off);
  server.on("/led2on", handle_led2on);
  server.on("/led2off", handle_led2off);
  server.onNotFound(handle_NotFound);
  
  server.begin();
  Serial.println("HTTP server started");
}
void loop() {
  server.handleClient();
  if(LED1status)
  {digitalWrite(LED1pin, HIGH);}
  else
  {digitalWrite(LED1pin, LOW);}
  
  if(LED2status)
  {digitalWrite(LED2pin, HIGH);}
  else
  {digitalWrite(LED2pin, LOW);}
}

void handle_OnConnect() {
  LED1status = LOW;
  LED2status = LOW;
  Serial.println("GPIO4 Status: OFF | GPIO5 Status: OFF");
  server.send(200, "text/html", SendHTML(LED1status,LED2status)); 
}

void handle_led1on() {
  LED1status = HIGH;
  Serial.println("GPIO4 Status: ON");
  server.send(200, "text/html", SendHTML(true,LED2status)); 
}

void handle_led1off() {
  LED1status = LOW;
  Serial.println("GPIO4 Status: OFF");
  server.send(200, "text/html", SendHTML(false,LED2status)); 
}

void handle_led2on() {
  LED2status = HIGH;
  Serial.println("GPIO5 Status: ON");
  server.send(200, "text/html", SendHTML(LED1status,true)); 
}

void handle_led2off() {
  LED2status = LOW;
  Serial.println("GPIO5 Status: OFF");
  server.send(200, "text/html", SendHTML(LED1status,false)); 
}

void handle_NotFound(){
  server.send(404, "text/plain", "Not found");
}

String SendHTML(uint8_t led1stat,uint8_t led2stat){
  String ptr = "<!DOCTYPE html> <html>\n";
  ptr +="<head><meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0, user-scalable=no\">\n";
  ptr +="<title>LED Control</title>\n";
  ptr +="<style>html { font-family: Helvetica; display: inline-block; margin: 0px auto; text-align: center;}\n";
  ptr +="body{margin-top: 50px;} h1 {color: #444444;margin: 50px auto 30px;} h3 {color: #444444;margin-bottom: 50px;}\n";
  ptr +=".button {display: block;width: 80px;background-color: #3498db;border: none;color: white;padding: 13px 30px;text-decoration: none;font-size: 25px;margin: 0px auto 35px;cursor: pointer;border-radius: 4px;}\n";
  ptr +=".button-on {background-color: #3498db;}\n";
  ptr +=".button-on:active {background-color: #2980b9;}\n";
  ptr +=".button-off {background-color: #34495e;}\n";
  ptr +=".button-off:active {background-color: #2c3e50;}\n";
  ptr +="p {font-size: 14px;color: #888;margin-bottom: 10px;}\n";
  ptr +="</style>\n";
  ptr +="</head>\n";
  ptr +="<body>\n";
  ptr +="<h1>ESP32 Web Server</h1>\n";
  ptr +="<h3>Using Access Point(AP) Mode</h3>\n";
  
   if(led1stat)
  {ptr +="<p>LED1 Status: ON</p><a class=\"button button-off\" href=\"/led1off\">OFF</a>\n";}
  else
  {ptr +="<p>LED1 Status: OFF</p><a class=\"button button-on\" href=\"/led1on\">ON</a>\n";}

  if(led2stat)
  {ptr +="<p>LED2 Status: ON</p><a class=\"button button-off\" href=\"/led2off\">OFF</a>\n";}
  else
  {ptr +="<p>LED2 Status: OFF</p><a class=\"button button-on\" href=\"/led2on\">ON</a>\n";}

  ptr +="</body>\n";
  ptr +="</html>\n";
  return ptr;
}

O/P:



WiFi Client Code:


WiFi OLED DIsplay(0.96inch I2C):

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

Adafruit_SSD1306 display(-1);

void setup()   
{                
	// initialize with the I2C addr 0x3C
	display.begin(SSD1306_SWITCHCAPVCC, 0x3C);  

	// Clear the buffer.
	display.clearDisplay();

	// Display Text
	display.setTextSize(1);
	display.setTextColor(WHITE);
	display.setCursor(0,28);
	display.println("Hello world!");
	display.display();
	delay(2000);
	display.clearDisplay();

	// Display Inverted Text
	display.setTextColor(BLACK, WHITE); // 'inverted' text
	display.setCursor(0,28);
	display.println("Hello world!");
	display.display();
	delay(2000);
	display.clearDisplay();

	// Changing Font Size
	display.setTextColor(WHITE);
	display.setCursor(0,24);
	display.setTextSize(2);
	display.println("Hello!");
	display.display();
	delay(2000);
	display.clearDisplay();

	// Display Numbers
	display.setTextSize(1);
	display.setCursor(0,28);
	display.println(123456789);
	display.display();
	delay(2000);
	display.clearDisplay();

	// Specifying Base For Numbers
	display.setCursor(0,28);
	display.print("0x"); display.print(0xFF, HEX); 
	display.print("(HEX) = ");
	display.print(0xFF, DEC);
	display.println("(DEC)"); 
	display.display();
	delay(2000);
	display.clearDisplay();

	// Display ASCII Characters
	display.setCursor(0,24);
	display.setTextSize(2);
	display.write(3);
	display.display();
	delay(2000);
	display.clearDisplay();

	// Scroll full screen
	display.setCursor(0,0);
	display.setTextSize(1);
	display.println("Full");
	display.println("screen");
	display.println("scrolling!");
	display.display();
	display.startscrollright(0x00, 0x07);
	delay(2000);
	display.stopscroll();
	delay(1000);
	display.startscrollleft(0x00, 0x07);
	delay(2000);
	display.stopscroll();
	delay(1000);    
	display.startscrolldiagright(0x00, 0x07);
	delay(2000);
	display.startscrolldiagleft(0x00, 0x07);
	delay(2000);
	display.stopscroll();
	display.clearDisplay();

	// Scroll part of the screen
	display.setCursor(0,0);
	display.setTextSize(1);
	display.println("Scroll");
	display.println("some part");
	display.println("of the screen.");
	display.display();
	display.startscrollright(0x00, 0x00);
}

void loop() {}


O/P:

.....Many More



BLE Code:


#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>


#define SERVICE_UUID        "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"

void setup() {
  Serial.begin(115200);
  Serial.println("Starting BLE work!");

  BLEDevice::init("Long name works now");
  BLEServer *pServer = BLEDevice::createServer();
  BLEService *pService = pServer->createService(SERVICE_UUID);
  BLECharacteristic *pCharacteristic = pService->createCharacteristic(
                                         CHARACTERISTIC_UUID,
                                         BLECharacteristic::PROPERTY_READ |
                                         BLECharacteristic::PROPERTY_WRITE
                                       );

  pCharacteristic->setValue("Hello World says Neil");
  pService->start();
  // BLEAdvertising *pAdvertising = pServer->getAdvertising();  // this still is working for backward compatibility
  BLEAdvertising *pAdvertising = BLEDevice::getAdvertising();
  pAdvertising->addServiceUUID(SERVICE_UUID);
  pAdvertising->setScanResponse(true);
  pAdvertising->setMinPreferred(0x06);  // functions that help with iPhone connections issue
  pAdvertising->setMinPreferred(0x12);
  BLEDevice::startAdvertising();
  Serial.println("Characteristic defined! Now you can read it in your phone!");
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(2000);
}

OTA Update Code and Support:

#include <WiFi.h>
#include <ESPmDNS.h>
#include <WiFiUdp.h>
#include <ArduinoOTA.h>

const char* ssid = "..........";
const char* password = "..........";

void setup() {
  Serial.begin(115200);
  Serial.println("Booting");
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    Serial.println("Connection Failed! Rebooting...");
    delay(5000);
    ESP.restart();
  }

  // Port defaults to 3232
  // ArduinoOTA.setPort(3232);

  // Hostname defaults to esp3232-[MAC]
  // ArduinoOTA.setHostname("myesp32");

  // No authentication by default
  // ArduinoOTA.setPassword("admin");

  // Password can be set with it's md5 value as well
  // MD5(admin) = 21232f297a57a5a743894a0e4a801fc3
  // ArduinoOTA.setPasswordHash("21232f297a57a5a743894a0e4a801fc3");

  ArduinoOTA
    .onStart([]() {
      String type;
      if (ArduinoOTA.getCommand() == U_FLASH)
        type = "sketch";
      else // U_SPIFFS
        type = "filesystem";

      // NOTE: if updating SPIFFS this would be the place to unmount SPIFFS using SPIFFS.end()
      Serial.println("Start updating " + type);
    })
    .onEnd([]() {
      Serial.println("\nEnd");
    })
    .onProgress([](unsigned int progress, unsigned int total) {
      Serial.printf("Progress: %u%%\r", (progress / (total / 100)));
    })
    .onError([](ota_error_t error) {
      Serial.printf("Error[%u]: ", error);
      if (error == OTA_AUTH_ERROR) Serial.println("Auth Failed");
      else if (error == OTA_BEGIN_ERROR) Serial.println("Begin Failed");
      else if (error == OTA_CONNECT_ERROR) Serial.println("Connect Failed");
      else if (error == OTA_RECEIVE_ERROR) Serial.println("Receive Failed");
      else if (error == OTA_END_ERROR) Serial.println("End Failed");
    });

  ArduinoOTA.begin();

  Serial.println("Ready");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
}

void loop() {
  ArduinoOTA.handle();
}

For More in Details: htpts://lastminuteengineers.com/esp32-ota-updates-arduino-ide/...


Bibliography:

https://circuits4you.com/2018/02/02/esp32-led-blink-example/

https://lastminuteengineers.com/creating-esp32-web-server-arduino-ide/

https://randomnerdtutorials.com/esp32-bluetooth-low-energy-ble-arduino-ide/

https://www.espressif.com/en/products/modules

https://www.youtube.com/

https://www.google.com/

https://www.instructables.com/

https://stackoverflow.com/

http://esp32.net/

https://en.wikipedia.org/wiki/ESP32

https://aws.amazon.com/

Friday, 1 May 2020

UV - An Application to sanitation, disinfection, and sterilization

Standard
The Ultra Violet Fire and Grace Elohim Meditation - YouTube

Search Results

Web results

Ultraviolet Applications:  Is Really It Matters !

Note: Before We go through this article, we need to have some basics on UV Rays. If you know this then, please ignore this paragraph.


WHAT is UV Radiation?


All radiation is a form of energy, most of which is invisible to the human eye. UV radiation is only one form of radiation and it is measured on a scientific scale called the electromagnetic (EM) spectrum. In simplest from UV radiation is the portion of the EM spectrum between X-rays and visible light.

HOW is radiation classified on the electromagnetic spectrum?

Electromagnetic radiation is all around us, though we can only see some of it. All EM radiation (also called EM energy) is made up of minute packets of energy or 'particles,' called photons, which travel in a wave-like pattern and move at the speed of light. The EM spectrum is divided into categories defined by a range of numbers. These ranges describe the activity level, or how energetic the photons are, and the size of the wavelength in each category. 

Diagram. Wavelength in centimeters, and approximate size examples. Radio, 10^4, buildings. 10^2, humans. Microwave, 1, honey bee. infrared, 10^-2, pinhead. visible, 10^-5, protozoans. Ultraviolet, 10^-6, molecules. X-ray, 10^-8, atoms. Gamma ray, 10^-10 and 10^-12, atomic nuclei. Image courtesy of NASA.



[IC: NASA]



For example, at the bottom of the spectrum radio waves have photons with low energies, so their wavelengths are long with peaks that are far apart. The photons of microwaves have higher energies, followed by infrared waves, UV rays, and X-rays. At the top of the spectrum, gamma rays have photons with very high energies and short wavelengths with peaks that are close together.


Mira's(Red Giant Star 30,000 Years Ago ) bow shock and hydrogen gas tail in ultraviolet, rendered in blue-visible light. PC: Wikipedia




Types of UV radiation?

Like all forms of light on the EM spectrum, UV radiation is classified by wavelength. Wavelength describes the distance between the peaks in a series of waves.
  • UVB rays have a short wavelength that reaches the outer layer of your skin (the epidermis)
  • UVA rays have a longer wavelength that can penetrate the middle layer of your skin (the dermis)

If UV radiation have on Human Body?

In humans, excessive exposure to UV radiation can result in acute and chronic harmful effects on the eye's dioptric system and retina. The risk is elevated at high altitudes and people living in high latitude areas where snow covers the ground right into early summer and sun positions even at zenith are low, are particularly at risk.  Skin, the circadian system, and the immune system can also be affected.

Example:

Ultraviolet photons harm the DNA molecules of living organisms in different ways. In one common damage event, adjacent thymine bases bond with each other, instead of across the "ladder". This "thymine dimer" makes a bulge, and the distorted DNA molecule does not function properly.


Sunburn effect (as measured by the UV Index) is the product of the sunlight spectrum (radiation intensity) and the erythemal action spectrum (skin sensitivity) across the range of UV wavelengths. Sunburn production per milliwatt is increased by almost a factor of 100 between the near UVB wavelengths of 315–295 nm


The differential effects of various wavelengths of light on the human cornea and skin are sometimes called the "erythemal action spectrum".] The action spectrum shows that UVA does not cause immediate reaction, but rather UV begins to cause photokeratitis and skin redness (with lighter skinned individuals being more sensitive) at wavelengths starting near the beginning of the UVB band at 315 nm, and rapidly increasing to 300 nm. The skin and eyes are most sensitive to damage by UV at 265–275 nm, which is in the lower UVC band. At still shorter wavelengths of UV, damage continues to happen, but the overt effects are not as great with so little penetrating the atmosphere. The WHO-standard ultraviolet index is a widely publicized measurement of total strength of UV wavelengths that cause sunburn on human skin, by weighting UV exposure for action spectrum effects at a given time and location. This standard shows that most sunburn happens due to UV at wavelengths near the boundary of the UVA and UVB band.






The above paragraphs are basics which can help you to understand about UV and Types. Now we will focus on It's Application to sanitation, disinfection, and sterilization.





As COVID-19 continues to ravage global populations, the world is singularly focused on finding ways to battle the novel coronavirus. Researchers there are developing ultraviolet LEDs that have the ability to decontaminate surfaces -- and potentially air and water -- that have come in contact with the SARS-CoV-2 virus.


"One major application is in medical situations -- the disinfection of personal protective equipment, surfaces, floors, within the HVAC systems, et cetera," . There is a small market already for UV-C disinfection products in medical contexts.


Indeed, much attention of late has turned to the power of ultraviolet light to inactivate the novel coronavirus. As a technology, ultraviolet light disinfection has been around for a while. And while practical, large-scale efficacy against the spread of SARS-CoV-2 has yet to be shown. UV light shows a lot of promise: SSLEEC member company Seoul Semiconductor in early April reported a "99.9% sterilization of coronavirus (COVID-19) in 30 seconds" with their UV LED products. Their technology is currently being adopted for automotive use, in UV LED lamps that sterilize the interior of unoccupied vehicles.


It's worth noting that not all UV wavelengths are alike. UV-A and UV-B -- the types we get a lot of here on Earth courtesy of the Sun -- have important uses, but the rare UV-C is the ultraviolet light of choice for purifying air and water and for inactivating microbes. These can be generated only via human-made processes.


UV-C light in the 253.76 -- 285 nm range most relevant for current disinfection technologies is also harmful to human skin, so for now it is mostly used in applications where no one is present at the time of disinfection. In fact, the World Health Organization warns against using ultraviolet disinfection lamps to sanitize hands or other areas of the skin -- even brief exposure to UV-C light can cause burns and eye damage.


Before the COVID-19 pandemic gained global momentum, materials scientists at SSLEEC were already at work advancing UV-C LED technology. This area of the electromagnetic spectrum is a relatively new frontier for solid-state lighting; UV-C light is more commonly generated via mercury vapor lamps. But now many technological advances are needed for the UV LED to reach its potential in terms of efficiency, cost, reliability and lifetime.


In a letter published in the journal ACS Photonics, the researchers reported a more elegant method for fabricating high-quality deep-ultraviolet (UV-C) LEDs that involves depositing a film of the semiconductor alloy aluminum gallium nitride (AlGaN) on a substrate of silicon carbide (SiC) -- a departure from the more widely used sapphire substrate.


According to Zollner (Scientist), using silicon carbide as a substrate allows for more efficient and cost-effective growth of high-quality UV-C semiconductor material than using sapphire. This, he explained, is due to how closely the materials' atomic structures match up.

"As a general rule of thumb, the more structurally similar (in terms of atomic crystal structure) the substrate and the film are to each other, the easier it is to achieve high material quality," he said. The better the quality, the better the LED's efficiency and performance. Sapphire is dissimilar structurally, and producing material without flaws and misalignments often requires complicated additional steps. Silicon carbide is not a perfect match, Zollner said, but it enables a high quality without the need for costly, additional methods.

In addition, silicon carbide is far less expensive than the "ideal" aluminum nitride substrate, making it more mass production-friendly, according to Zollner.

Portable, fast-acting water disinfection was among the primary applications the researchers had in mind as they were developing their UV-C LED technology; the diodes' durability, reliability and small form factor would be a game changer in less developed areas of the world where clean water is not available.
The emergence of the COVID-19 pandemic has added another dimension. As the world races to find vaccines, therapies and cures for the disease, disinfection, decontamination and isolation are the few weapons we have to defend ourselves, and the solutions will need to be deployed worldwide. In addition to UV-C for water sanitation purposes, UV-C light could be integrated into systems that turn on when no one is present.
"This would provide a low-cost, chemical-free and convenient way to sanitize public, retail, personal and medical spaces." 

UV Wavelengths and Applications:


230–365 nm: UV-ID, label tracking, barcodes
230–400 nm: Optical sensors, various instrumentation
240–280 nmDisinfection, decontamination of surfaces and water (DNA absorption has a peak at 260 nm), germicidal lamps
200–400 nmForensic analysis, drug detection
270–360 nmProtein analysis, DNA sequencingdrug discovery
280–400 nmMedical imaging of cells
300–320 nmLight therapy in medicine
300–365 nmCuring of polymers and printer inks
350–370 nmBug zappers (flies are most attracted to light at 365 nm)

Examples of Exisitng UVC Lamp based Products:
1:
2:
3:

4:
5:
6:
7: HOW UVC AIR PURIFIER WORKS
8:

9:

10:


Source:

https://www.sciencedaily.com/releases/2020/04/200414173251.htm

https://www.fda.gov/radiation-emitting-products/tanning/ultraviolet-uv-radiation

https://en.wikipedia.org/wiki/Ultraviolet_germicidal_irradiation

https://www.mrsa-uv.com/

https://en.wikipedia.org/wiki/Mira

https://www.google.com/

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