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Preview segment lighting, calculate resistor values, and validate multiplex timing in one UI. Share firmware-ready lookup tables for common cathode or common anode displays within seconds.
// Arduino 7-Segment Display Code
// Wiring: Common Cathode
// Resistor: 150Ω (1/4W or higher)
const uint8_t SEGMENT_MAP[16] = {
0x3F // 0,
0x06 // 1,
0x5B // 2,
0x4F // 3,
0x66 // 4,
0x6D // 5,
0x7D // 6,
0x07 // 7,
0x7F // 8,
0x6F // 9,
0x77 // A,
0x7C // B,
0x39 // C,
0x5E // D,
0x79 // E,
0x71 // F,
0x3D // G,
0x76 // H,
0x06 // I,
0x1E // J,
0x75 // K,
0x38 // L,
0x55 // M,
0x54 // N,
0x3F // O,
0x73 // P,
0x67 // Q,
0x50 // R,
0x6D // S,
0x78 // T,
0x3E // U,
0x1C // V,
0x2A // W,
0x76 // X,
0x6E // Y,
0x5B // Z,
0x00 // ,
0x40 // -,
0x08 // _,
0x48 // =,
0x63 // *,
0x22 // ",
0x02 // ',
0x63 // °,
0x00 // .,
0x04 // ,,
0x06 // !,
0x53 // ?,
0x52 // /,
0x64 // \,
0x39 // [,
0x0F // ],
0x39 // (,
0x0F // ),
0x61 // <,
0x43 // >,
0x06 // |
};
// Current display value: HELLO
const uint8_t displayDigits[] = {0x76, 0x79, 0x38, 0x38, 0x3F};
void setup() {
// Configure segment pins (A-G, DP) as outputs
// Pins 2-9 for segments A-G and DP
for (int i = 2; i <= 9; i++) {
pinMode(i, OUTPUT);
}
}
void displayDigit(uint8_t pattern) {
for (int i = 0; i < 8; i++) {
digitalWrite(i + 2, pattern & (1 << i));
}
}
void loop() {
// Display each digit in sequence
for (int digit = 0; digit < 5; digit++) {
displayDigit(displayDigits[digit]);
delay(5); // 5ms per digit for multiplexing
}
}Complete runnable code for your selected platform, including initialization and display functions.
const uint8_t digits[] = {0x76, 0x79, 0x38, 0x38, 0x3F};Copy directly into your microcontroller code. Each byte represents the segment pattern for one digit.
Get wiring-ready data in three quick steps.
Select decimal, hex, or binary input and set the display wiring to common cathode or common anode so the logic polarity is correct.
Set digit count, refresh rate, and LED electrical ratings. The app warns if duty cycle or voltage limits are unsafe.
Click Generate to lock the configuration, copy the lookup mask, and share the parameters with firmware teammates.
A manufacturing engineer needs to refurbish a four-digit production counter with modern drivers while keeping the existing 7 segment hardware.
The engineer enters hex values to confirm segment masks align with the existing PLC displays.
They increase refresh to 320 Hz, keeping per-digit frequency above 80 Hz to remove flicker warnings.
Adjusting LED current from 20 mA to 12 mA raises the recommended resistor, preventing thermal runaway.
The counter ships with stable brightness, compliant current limits, and annotated firmware arrays generated from the calculator.
The current release assumes the standard A–G segment order. For bespoke PCBs, share the exported hex mask with your firmware team and remap bits as needed.
Aim for at least 60 Hz per digit. For four digits that means 240 Hz overall. The warning banner triggers whenever the per-digit rate falls below the comfort threshold.
Yes. Copy the generated masks and parameter summary into your documentation or version control to keep hardware, firmware, and QA aligned.
Future updates will add customizable glyph libraries. For now, combine the binary mask output with custom lookup tables for characters outside 0–F.
Absolutely. Use the hex mask for direct MCU control or translate it for driver IC pinouts such as MAX7219 or TM1637.
Use the calculated resistor as the closest standard value per segment in single-digit applications. For multiplexed displays, treat it as the per-segment series resistor.
Yes. Drop the current to reduce power draw or meet thermal limits—the calculator instantly updates the suggested resistor.
It highlights overcurrent risks. For precise thermal analysis, combine the resistor output with your LED datasheet’s derating curves.
Yes. The interface inherits the site-wide dark mode, making it easier to reference on the bench in low-light labs.
Whenever you change digit count, refresh rate, or LED characteristics. The warnings ensure each new configuration stays within spec.
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