Introduction If you’ve ever worked with a proximity card reader (125kHz or 13.56MHz), a fingerprint scanner, or an old-school magnetic stripe swipe, you’ve almost certainly encountered the Wiegand protocol. In the embedded world, the wiegand.h header file represents the standard interface for driving these devices via GPIO on microcontrollers like Arduino, ESP32, STM32, or Raspberry Pi Pico.
while (1) vTaskDelay(pdMS_TO_TICKS(1000));
void app_main() wiegand_config_t cfg = .pin_d0 = GPIO_NUM_4, .pin_d1 = GPIO_NUM_5, .bit_timeout_us = 2500, .packet_timeout_us = 15000, .pullup_enable = true ; wiegand_init(&cfg); wiegand_set_callback(card_received); wiegand.h
#ifndef WIEGAND_H #define WIEGAND_H #include <stdint.h> #include <stdbool.h>
Remember: Implement it correctly once, and you’ll support every major card reader on the market. Have you battled Wiegand jitter or bit‑order issues? Share your experience below. Introduction If you’ve ever worked with a proximity
// Public API void wiegand_init(const wiegand_config_t *config); void wiegand_set_callback(wiegand_callback_t cb); void wiegand_reset(void); bool wiegand_available(void); uint32_t wiegand_get_facility(void); uint32_t wiegand_get_card(void); int wiegand_get_bit_count(void);
void IRAM_ATTR on_d1_falling() record_bit(1); Have you battled Wiegand jitter or bit‑order issues
// Example ISR (pseudo-code) void IRAM_ATTR on_d0_falling() record_bit(0);
// Callback type for completed card reads typedef void (*wiegand_callback_t)(uint32_t facility_code, uint32_t card_number, int bits_received);
#endif // WIEGAND_H 1. Interrupt‑Driven Bit Capture The only reliable way to read Wiegand is via edge-triggered interrupts on the D0 and D1 pins. Polling will miss microsecond pulses.