dunkirk.sh
🥑 meltybrain avocado
feat: add blinking led
author
Kieran Klukas
date
(Jul 18, 2026, 1:00 AM -0700)
commit
8535538b
8535538b39870a099877ca422984b4963354c53a
parent
f27e731c
f27e731c075ead5eb17c379614c07b39780c4c72
+85
+1
firmware/CMakeLists.txt
+1
firmware/CMakeLists.txt
+53
firmware/src/led/head_led.c
+53
firmware/src/led/head_led.c
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#include "head_led.h"
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#include "hw_pins.h"
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#include "hardware/gpio.h"
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#include <math.h>
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/* Tunables. */
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#define SPIN_OMEGA_MIN 10.0f /* rad/s; below this the robot is "idle" */
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#define STROBE_WINDOW 0.35f /* rad (~20 deg) total width of the dot */
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#define REF_HEADING 0.0f /* heading at which the dot appears */
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#define STALE_US 200000u /* no estimate for this long => idle */
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#define IDLE_BLINK_US 250000u /* idle heartbeat half-period (2 Hz) */
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static float s_heading;
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static float s_omega;
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static uint32_t s_update_us;
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static bool s_have;
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void head_led_init(void) {
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gpio_init(PIN_HEAD_LED);
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gpio_set_dir(PIN_HEAD_LED, GPIO_OUT);
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gpio_put(PIN_HEAD_LED, 0);
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s_have = false;
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}
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void head_led_on_estimate(const heading_estimate_t *est, uint32_t now_us) {
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s_heading = est->heading;
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s_omega = est->omega;
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s_update_us = now_us;
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s_have = true;
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}
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static float wrap_pi(float a) {
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const float pi = (float)M_PI;
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while (a >= pi) a -= 2.0f * pi;
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while (a < -pi) a += 2.0f * pi;
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return a;
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}
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void head_led_tick(uint32_t now_us) {
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bool stale = !s_have || (now_us - s_update_us) > STALE_US;
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if (!stale && fabsf(s_omega) > SPIN_OMEGA_MIN) {
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/* Extrapolate heading to "now" so the dot stays put between the
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* (slower) estimate updates, then light the LED within a small
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* angular window around the reference heading. */
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float dt = (float)(now_us - s_update_us) * 1e-6f;
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float err = wrap_pi(s_heading + s_omega * dt - REF_HEADING);
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gpio_put(PIN_HEAD_LED, fabsf(err) < (STROBE_WINDOW * 0.5f));
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} else {
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/* Idle heartbeat. */
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gpio_put(PIN_HEAD_LED, ((now_us / IDLE_BLINK_US) & 1u) == 0u);
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}
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}
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firmware/src/led/head_led.h
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firmware/src/led/head_led.h
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#pragma once
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/*
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* Heading-indicator LED (meltybrain "stationary dot").
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*
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* The LED sits on PIN_HEAD_LED via a PN2222A (drive high = lit). When the
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* robot is spinning with a live heading estimate, the LED is pulsed once per
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* revolution as the estimated heading sweeps past a fixed reference angle.
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* To the eye that paints a single stationary bright dot the driver can use as
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* "front." When idle (not spinning, or no fresh estimate), it slow-blinks as
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* a heartbeat so you can see the firmware is alive.
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*
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* Heading is extrapolated from the last estimate using omega so the dot stays
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* crisp even though estimates arrive slower than the control loop.
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*/
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#include <stdint.h>
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#include "estimation/heading_estimate.h"
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void head_led_init(void);
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/* Feed a fresh heading estimate (call when a new one is available). */
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void head_led_on_estimate(const heading_estimate_t *est, uint32_t now_us);
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/* Update the LED output. Call every control-loop iteration. */
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void head_led_tick(uint32_t now_us);
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firmware/src/main.c
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firmware/src/main.c
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#include "safety/watchdog.h"
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#include "safety/battery.h"
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#include "safety/rc_health.h"
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#include "led/head_led.h"
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#define RAD_TO_DEG 57.2958f
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#define CRSF_LINK_TIMEOUT_MS 500
···
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crsf_init();
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rc_health_init();
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head_led_init();
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crsf_state_t rc = {0};
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printf("Core 1 ready [%s]. Waiting for RC link...\n", sensor_primary.name);
···
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if (shared_est.ready) {
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est = shared_est.est;
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shared_est.ready = false;
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head_led_on_estimate(&est, time_us_32());
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}
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spin_unlock(est_lock, irq);
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···
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battery_low() ? " LOW-BAT" : "",
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!rc_health_ok() ? " STALE-RC" : "");
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}
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head_led_tick(time_us_32());
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watchdog_feed_core1();
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sleep_us(CONTROL_LOOP_SLEEP_US);