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Arduino Soil Moisture Sensor

 How the Soil Moisture Sensor Works

Resistive Sensor

Uses two metal probes to measure electrical resistance. Wet soil has lower resistance, while dry soil has higher resistance.

Capacitive Sensor

Measures changes in soil capacitance and has no exposed metal parts. It provides more stable and long-lasting performance.

Both sensors provide an analog output that Arduino reads.

Wiring the Soil Moisture Sensor

Soil Sensor → Arduino
VCC         → 5V
GND         → GND
AO          → A0

The digital output (DO) pin is optional and can be used with a preset threshold.

Arduino Code (Basic Reading)


int soilPin = A0;
int soilValue = 0;

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

void loop() {
  soilValue = analogRead(soilPin);

  Serial.print("Soil Moisture Value: ");
  Serial.println(soilValue);

  delay(1000);
}

Understanding Soil Moisture Values

Sensor Value Soil Condition
0 – 300 Very Wet
300 – 600 Moist
600 – 900 Dry
900 – 1023 Very Dry

Values may vary depending on soil type. Always calibrate with dry and wet soil.

Improved Code with Moisture Status


int soilPin = A0;
int soilValue = 0;

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

void loop() {
  soilValue = analogRead(soilPin);

  Serial.print("Soil Moisture: ");
  Serial.print(soilValue);

  if (soilValue < 300) {
    Serial.println(" - WET");
  }
  else if (soilValue < 600) {
    Serial.println(" - MOIST");
  }
  else {
    Serial.println(" - DRY");
  }

  delay(1000);
}

Testing the Sensor

  1. Upload the code to Arduino
  2. Open the Serial Monitor
  3. Set baud rate to 9600
  4. Insert the sensor into soil
  5. Add water and observe changes

Wet soil produces lower values, while dry soil produces higher values.

Troubleshooting

  • Always reads 1023: Sensor not properly inserted
  • No value change: Loose wiring or faulty sensor
  • Unstable readings: Electrical noise or dry air
  • Corrosion: Use capacitive sensor instead of resistive

Optional Upgrades

  • Add relay and water pump for automatic irrigation
  • Add LCD or OLED display
  • Use ESP8266/ESP32 for IoT monitoring
  • Log data to SD card for analysis.
[mai mult...]

Review Attack Shark X3Pro mouse

The Attack Shark X3 Pro wireless gaming mouse is an excellent budget option that delivers performance and features normally found in more expensive models. It is designed for competitive gaming while remaining comfortable and reliable for everyday use, making it a strong quality-to-price choice.

Why it’s worth buying (value for money):

  1. High-performance sensor:
    The X3 Pro is equipped with a PixArt PAW3395 optical sensor, which is widely recognized for its accuracy, low latency, and reliability. This ensures precise tracking for FPS, MOBA, and fast-paced competitive games, even at high DPI settings.
  2. Lightweight design:
    With a weight of approximately 55–60 grams, the mouse is very light, allowing for quick movements and reduced hand fatigue during long gaming sessions. This lightweight construction is a major advantage at this price point.
  3. Wireless performance:
    The mouse supports 2.4 GHz wireless connectivity, delivering a stable, low-latency connection comparable to wired mice. This makes it suitable for competitive gaming without cable drag.
  4. Long battery life:
    Thanks to efficient power management, the X3 Pro offers excellent battery life, allowing extended use without frequent charging, which is ideal for both gaming and productivity.
  5. Good build quality:
    Despite its affordable price, the mouse feels solid and well-assembled. The buttons provide crisp clicks, and the scroll wheel is precise, contributing to a premium feel relative to its cost.
  6. Customizable software:
    The companion software allows you to adjust DPI levels, polling rate, button assignments, and macros, giving users control over performance tuning and personalization.
[mai mult...]

Review Attack Shark x85 keyboard

The Attack Shark X85 wireless mechanical keyboard delivers excellent performance and features for its price class. It is a 75% layout mechanical keyboard with a compact design that retains essential keys while saving desk space, making it ideal for both gaming and daily productivity.

Why it’s worth buying (value for money):

  1. Versatile connectivity: You can use it in wired (USB-C), 2.4 GHz wireless, or Bluetooth mode, allowing seamless switching between multiple devices (PC, laptop, tablet).
  2. Premium typing feel: The keyboard uses a gasket mount structure with five layers of sound-absorbing material, which results in a smoother, quieter typing experience that punches above its price point.
  3. Hot-swappable switches: You can easily replace or customize the mechanical switches without soldering. This is rare at this price level and adds long-term value.
  4. Durable keycaps: Cherry-profile PBT keycaps are more wear-resistant than typical ABS caps, maintaining a clean look after extended use.
  5. Long battery life: A 5000 mAh battery supports extended wireless sessions.
  6. RGB lighting & control knob: Customizable RGB backlighting and an aluminum CNC volume/lighting control knob add usability and aesthetics without a high cost.

Overall, for gamers, programmers, or general users on a budget, the Attack Shark X85 offers very strong performance and features relative to its price, making it a compelling budget mechanical keyboard option.

[mai mult...]

Arduino Fingerprint Sensor

Required Components

Component Quantity Description
Arduino Uno / Nano / Mega 1 Main controller
Fingerprint Sensor (R307 / ZFM-20 / Adafruit) 1 Biometric identification
16×2 LCD with I2C Module 1 Display user messages
12V Solenoid Lock 1 Door/box locking mechanism
5V Relay Module 1 Controls solenoid lock
12V Power Supply 1 Powers solenoid
Jumper Wires – Connections

The fingerprint sensor scans the user’s finger. Arduino checks if the fingerprint matches a stored ID. If it matches, the relay is activated and unlocks the solenoid lock. The LCD shows:

  • Scanning
  • Access Granted
  • Access Denied

Fingerprint Sensor → Arduino

VCC → 5V
GND → GND
TX  → D2
RX  → D3

I2C LCD → Arduino

VCC → 5V
GND → GND
SDA → A4
SCL → A5

Relay Module → Arduino

IN  → D8
VCC → 5V
GND → GND

Solenoid Lock Power Wiring

12V+ → COM on Relay
NO   → Solenoid +
Solenoid - → 12V -

IMPORTANT: Use a diode (1N4007) across solenoid terminals to prevent voltage spikes.

Arduino Code (Copy & Paste)

This code controls the fingerprint module, LCD display, and solenoid lock.


#include <Adafruit_Fingerprint.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <SoftwareSerial.h>

SoftwareSerial fingerSerial(2, 3); // RX, TX
Adafruit_Fingerprint finger = Adafruit_Fingerprint(&fingerSerial);
LiquidCrystal_I2C lcd(0x27, 16, 2);

int relayPin = 8;

void setup() {
lcd.init();
lcd.backlight();

pinMode(relayPin, OUTPUT);
digitalWrite(relayPin, LOW); // lock OFF at start

lcd.setCursor(0, 0);
lcd.print("Fingerprint");
lcd.setCursor(0, 1);
lcd.print("Access System");

delay(2000);
lcd.clear();

finger.begin(57600);
if (finger.verifyPassword()) {
lcd.print("Sensor Ready");
} else {
lcd.print("Sensor Error");
while (1);
}
delay(2000);
lcd.clear();
}

void loop() {
lcd.setCursor(0, 0);
lcd.print("Place Finger...");
lcd.setCursor(0, 1);
lcd.print(" ");

int result = getFingerprintID();

if (result >= 0) {
lcd.clear();
lcd.print("Access Granted");
unlockDoor();
} else if (result == -1) {
lcd.clear();
lcd.print("Access Denied");
delay(1500);
}

lcd.clear();
}

int getFingerprintID() {
finger.getImage();
if (finger.image2Tz() != FINGERPRINT_OK) return -1;
if (finger.fingerSearch() != FINGERPRINT_OK) return -1;

return finger.fingerID; // valid ID returned
}

void unlockDoor() {
digitalWrite(relayPin, HIGH); // open lock
delay(3000); // unlock duration
digitalWrite(relayPin, LOW); // lock again
}

You must add fingerprints before using the system.

  1. In Arduino IDE, go to File → Examples → Adafruit Fingerprint Sensor Library → Enroll
  2. Upload the sketch
  3. Open Serial Monitor
  4. Type the fingerprint ID number (1–127)
  5. Place finger twice when instructed

Fingerprint is now stored.

LCD Display Messages

Event Message
Startup Fingerprint Access System
Ready Sensor Ready
Waiting Place Finger…
Match Access Granted
No Match Access Denied

Troubleshooting

  • Fingerprint not detected: TX/RX wiring reversed
  • LCD not showing text: Wrong I2C address (try 0x3F)
  • Solenoid not activating: Check relay NO/COM wiring
  • Machine resets: Solenoid drawing current — use separate 12V supply.
[mai mult...]