Wiegand.h

At its simplest, wiegand.h is a C/C++ header file that defines functions, constants, and data structures for decoding the Wiegand protocol using interrupts on a microcontroller. It abstracts away the low-level timing dependencies of the physical Wiegand interface.

// wiegand.h #pragma once #include <stdint.h>

So the next time you swipe a badge and a door unlocks, remember: somewhere, in the firmware of that reader, an interrupt service routine tied to a wiegand.h just fired—capturing your identity, one 50µs pulse at a time. wiegand.h

Have you battled Wiegand jitter or bit‑order issues? Share your experience below.

#include <Arduino.h> // Assuming Arduino/ESP32 framework At its simplest, wiegand

[1 bit Even Parity] [8 bits Facility Code] [16 bits Card Number] [1 bit Odd Parity]

| Symptom | Likely Cause | Fix | |---------|--------------|-----| | Missing bits | ISR too slow | Move ISR to RAM, disable other interrupts | | Wrong card ID | Pin swapping | Swap D0/D1 in begin() | | Random timeouts | Missing pull-ups | Enable INPUT_PULLUP or add 2.2k resistors | | Duplicate reads | No frame flush | Call flush() after isComplete() | | 26-bit reads as 0 | Type overflow | Use uint64_t for 34+ bit formats | Have you battled Wiegand jitter or bit‑order issues

The only reliable way to read Wiegand is via on the D0 and D1 pins. Polling will miss microsecond pulses.