Here’s a ready-to-run Proteus setup for Arduino UNO R3 + DHT11 (with code, wiring, and sim tips).

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1) What to place in Proteus

• Arduino UNO R3

• DHT11 sensor (the 4-pin DIP model or the 3-pin module—either is fine)

• 10 kΩ pull-up resistor (Data → 5V) if you use the raw 4-pin DHT11

• Virtual Terminal (to see Serial output)

• Power rails: +5V and GND

Tip: Double-click the DHT11 in Proteus and set its Temperature and Humidity properties (e.g., 25 °C, 55 %RH) to simulate different readings.

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2) Wiring (UNO R3 ↔ DHT11)

For the 4-pin DHT11 (facing the grill/front, pins left→right: VCC, DATA, NC, GND):

• DHT11 VCC → 5V

• DHT11 DATA → UNO D2

• DHT11 GND → GND

• 10 kΩ from DATA → 5V (pull-up)

For a 3-pin DHT11 module (usually VCC–DATA–GND):

• VCC → 5V, DATA → D2, GND → GND (module usually has onboard pull-up)

Virtual Terminal:

• UNO TX (D1) → VT RX

• UNO GND → VT GND

• Set VT baud to 9600

UNO settings in Proteus:

• Double-click UNO → Program File = your compiled .hex, Clock = 16 MHz

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3) Arduino code (uses Adafruit DHT library)

Install libraries (Arduino IDE → Library Manager):

• DHT sensor library (by Adafruit)

• Adafruit Unified Sensor

#include <DHT.h>

#define DHTPIN 2      // DHT11 data on UNO D2
#define DHTTYPE DHT11
DHT dht(DHTPIN, DHTTYPE);

void setup() {
  Serial.begin(9600);
  dht.begin();              // initializes timing for DHT
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.println(F("DHT11 test (UNO R3 + Proteus)"));
}

void loop() {
  // DHT11 max ~1 Hz; read every 2s for reliability
  static unsigned long last = 0;
  if (millis() - last < 2000) return;
  last = millis();

  float h = dht.readHumidity();
  float t = dht.readTemperature();      // °C
  float f = dht.readTemperature(true);  // °F

  if (isnan(h) || isnan(t) || isnan(f)) {
    Serial.println(F("DHT11 read failed"));
    // quick error blink
    digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
    return;
  }

  // Compute heat index as an example
  float hi = dht.computeHeatIndex(f, h);  // in °F
  float hiC = (hi - 32) * 5.0 / 9.0;

  Serial.print(F("T: ")); Serial.print(t, 1); Serial.print(F(" °C  "));
  Serial.print(F("H: ")); Serial.print(h, 1); Serial.print(F(" %RH  "));
  Serial.print(F("HI: ")); Serial.print(hiC, 1); Serial.println(F(" °C"));

  // good read blink
  digitalWrite(LED_BUILTIN, HIGH); delay(40);
  digitalWrite(LED_BUILTIN, LOW);
}

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4) Get the HEX & run in Proteus

Arduino IDE 2.x: Sketch → Export compiled Binary → use YourSketch.ino.hex.
Load that HEX into the UNO in Proteus → set Clock 16 MHz → press Run ▶️.
Open the Virtual Terminal (9600 baud) to see temperature/humidity/heat-index prints.

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5) Troubleshooting (DHT11 + Proteus)

• No readings / “read failed”: ensure pull-up on DATA (10 kΩ) or use a 3-pin module; keep D2 pin correct; don’t read faster than once per 2 s.

• Garbled serial: mismatch baud—set VT to 9600 and don’t connect UNO RX (D0) unless needed.

• Program halts: wrong board/clock → recompile for Arduino Uno and set 16 MHz in Proteus.

• Flat values: edit the DHT11 model’s Temperature/Humidity properties to new values and rerun.