LED Level Indicator: Tank and Silo Fill Display

Knowing the fill level of your water tank, diesel storage, or grain silo is essential for both homes and industries in India. An LED level indicator with a bright bar graph or percentage display eliminates guesswork and prevents overflow or dry-running. This guide covers sensor selection, display options, and remote monitoring.

Applications for Level Indicators

• Overhead water tanks: The most common application in Indian homes
• Diesel/fuel storage: Industrial and commercial fleet management
• Grain silos: Agricultural storage monitoring
• Chemical tanks: Industrial process control
• Rainwater harvesting: Track collected water levels

Sensor Technologies for Level Measurement

• Ultrasonic (HC-SR04/JSN-SR04T): Non-contact, measures from top. Best for water tanks. Rs.60-300.
• Float switch array: Multiple float switches at different heights. Simple but limited resolution. Rs.50-200.
• Capacitive probe: Continuous measurement through tank wall. Rs.200-500.
• Pressure sensor: Measures hydrostatic pressure at tank bottom. Very accurate for liquids. Rs.300-800.

LED Bar Graph Level Display

A 10-segment multi-colour bar graph is the most intuitive level indicator:

• Green: 70-100% (full/good)
• Yellow: 30-70% (moderate)
• Red: 0-30% (low, needs refill)

int level = measureLevel(); // 0-100%
int bars = map(level, 0, 100, 0, 10);
for(int i=0; i<10; i++) {
  digitalWrite(barPins[i], i < bars ? HIGH : LOW);
}

Seven-Segment Percentage Display

Show the exact percentage on a TM1637 or MAX7219 display alongside the bar graph for precise monitoring. Useful in industrial settings where exact levels matter for process control.

Remote Monitoring with WiFi

Use ESP32 to publish level data to the cloud:

• Check your water tank level from your phone while at work
• Get alerts when the tank is full (turn off pump) or low (order water tanker)
• Historical charts showing water usage patterns
• Integration with home automation (auto-start pump at 20%, auto-stop at 95%)

Alert Systems for High and Low Levels

• Buzzer alarm when level drops below 10% (dry-running protection)
• Relay output to automatically stop pump at 95% (overflow prevention)
• SMS/WhatsApp alert via ESP32 for remote notification
• Red flashing LED for critical low level

Waterproofing for Tank Installation

• Use JSN-SR04T waterproof ultrasonic sensor for tank-top mounting
• Seal all cable entry points with cable glands (IP68 rated)
• Mount the display indoors in a visible location (kitchen or pump room)
• Use shielded cables for long runs between tank and display

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