diff --git a/firmware/src/cli.h b/firmware/src/cli.h
index 96ceeb9..a6bf1d8 100644
--- a/firmware/src/cli.h
+++ b/firmware/src/cli.h
@@ -9,7 +9,7 @@
 
 typedef void (*cmd_handler_t)(int argc, char *argv[]);
 
-void cli_init();
+void cli_init(const char *prompt, const char *logo);
 void cli_register(const char *cmd, cmd_handler_t handler, const char *help);
 void cli_run();
 void cli_fps_count(int core);
diff --git a/firmware/src/main.c b/firmware/src/main.c
index c6946d4..42af08e 100644
--- a/firmware/src/main.c
+++ b/firmware/src/main.c
@@ -46,6 +46,10 @@ void report_usb_hid()
 
     uint64_t now = time_us_64();
 
+    if (memcmp(cardio.current, "\0\0\0\0\0\0\0\0\0", 9) != 0) {
+        rgb_set_rainbow_speed(255);
+    }
+
     if ((memcmp(cardio.current, cardio.reported, 9) != 0) &&
         (now - cardio.report_time > 1000000)) {
 
@@ -70,10 +74,6 @@ static void core1_loop()
         if (mutex_try_enter(&core1_io_lock, NULL)) {
             mutex_exit(&core1_io_lock);
         }
-        rgb_set_color(0, 0x800000);
-        rgb_set_color(1, 0x008000);
-        rgb_set_color(2, 0x000080);
-        rgb_set_color(3, 0x808080);
         rgb_update();
         cli_fps_count(1);
         sleep_ms(1);
diff --git a/firmware/src/pn532.c b/firmware/src/pn532.c
index 31458da..8f08adc 100644
--- a/firmware/src/pn532.c
+++ b/firmware/src/pn532.c
@@ -59,14 +59,14 @@ static bool pn532_wait_ready()
 {
     uint8_t status = 0;
 
-    for (int retry = 0; retry < 50; retry++) {
+    for (int retry = 0; retry < 30; retry++) {
         if (pn532_read(&status, 1) == 1 && status == 0x01) {
             return true;
         }
         if (wait_loop) {
             wait_loop();
         }
-        sleep_ms(1);
+        sleep_us(1000);
     }
 
     return false;
diff --git a/firmware/src/rgb.c b/firmware/src/rgb.c
index aa354ea..8b4dbf1 100644
--- a/firmware/src/rgb.c
+++ b/firmware/src/rgb.c
@@ -83,6 +83,80 @@ uint32_t rgb32_from_hsv(uint8_t h, uint8_t s, uint8_t v)
     }
 }
 
+static inline uint32_t apply_level(uint32_t color)
+{
+    unsigned r = (color >> 16) & 0xff;
+    unsigned g = (color >> 8) & 0xff;
+    unsigned b = color & 0xff;
+
+    r = r * aic_cfg->led.level / 255;
+    g = g * aic_cfg->led.level / 255;
+    b = b * aic_cfg->led.level / 255;
+
+    return r << 16 | g << 8 | b;
+}
+
+/* 6 segment regular hsv color wheel, better color cycle
+ * https://www.arnevogel.com/rgb-rainbow/
+ * https://www.instructables.com/How-to-Make-Proper-Rainbow-and-Random-Colors-With-/
+ */
+#define COLOR_WHEEL_SIZE 256
+static uint32_t color_wheel[COLOR_WHEEL_SIZE];
+static void generate_color_wheel()
+{
+    static uint8_t old_level = 0;
+    if (old_level == aic_cfg->led.level) {
+        return;
+    }
+    old_level = aic_cfg->led.level;
+
+    for (int i = 0; i < COLOR_WHEEL_SIZE; i++) {
+        color_wheel[i] = rgb32_from_hsv(i, 250, 255);
+        color_wheel[i] = apply_level(color_wheel[i]);
+    }
+}
+
+#define RAINBOW_PITCH 37
+#define RAINBOW_MIN_SPEED 1
+static uint32_t rainbow_speed = RAINBOW_MIN_SPEED;
+
+static void rainbow_update()
+{
+    static uint64_t last = 0;
+    uint64_t now = time_us_64();
+    if (now - last < 33333) { // no faster than 30Hz
+        return;
+    }
+    last = now;
+
+    static uint32_t rotator = 0;
+    rotator = (rotator + rainbow_speed) % COLOR_WHEEL_SIZE;
+
+    for (int i = 0; i < ARRAY_SIZE(rgb_buf); i++) {
+        uint32_t index = (rotator + RAINBOW_PITCH * i) % COLOR_WHEEL_SIZE;
+        rgb_buf[i] = color_wheel[index];
+    }
+}
+
+void rgb_set_rainbow_speed(uint8_t speed)
+{
+    rainbow_speed = speed / 8;
+}
+
+static void rainbow_speed_down()
+{
+    static uint64_t last = 0;
+    uint64_t now = time_us_64();
+    if (now - last < 200000) {
+        return;
+    }
+    last = now;
+
+    if (rainbow_speed > RAINBOW_MIN_SPEED) {
+        rainbow_speed = rainbow_speed * 95 / 100;
+    }
+}
+
 static void drive_led()
 {
     static uint64_t last = 0;
@@ -97,19 +171,6 @@ static void drive_led()
     }
 }
 
-static inline uint32_t apply_level(uint32_t color)
-{
-    unsigned r = (color >> 16) & 0xff;
-    unsigned g = (color >> 8) & 0xff;
-    unsigned b = color & 0xff;
-
-    r = r * aic_cfg->led.level / 255;
-    g = g * aic_cfg->led.level / 255;
-    b = b * aic_cfg->led.level / 255;
-
-    return r << 16 | g << 8 | b;
-}
-
 void rgb_set_color(unsigned index, uint32_t color)
 {
     if (index >= ARRAY_SIZE(rgb_buf)) {
@@ -144,12 +205,17 @@ void rgb_set_brg(unsigned index, const uint8_t *brg_array, size_t num)
 void rgb_init()
 {
     uint pio0_offset = pio_add_program(pio0, &ws2812_program);
-
     gpio_set_drive_strength(RGB_PIN, GPIO_DRIVE_STRENGTH_2MA);
     ws2812_program_init(pio0, 0, pio0_offset, RGB_PIN, 800000, false);
+    
+    generate_color_wheel();
 }
 
 void rgb_update()
 {
+    generate_color_wheel();
+
+    rainbow_update();
+    rainbow_speed_down();
     drive_led();
 }
diff --git a/firmware/src/rgb.h b/firmware/src/rgb.h
index 5e9331e..307b45d 100644
--- a/firmware/src/rgb.h
+++ b/firmware/src/rgb.h
@@ -20,5 +20,6 @@ uint32_t rgb32_from_hsv(uint8_t h, uint8_t s, uint8_t v);
 
 void rgb_set_color(unsigned index, uint32_t color);
 void rgb_set_color_all(uint32_t color);
+void rgb_set_rainbow_speed(uint8_t speed);
 
 #endif