 Sketch sketch = {
   0,
   LAUNCHSTATE_DISARMED,
+  LAUNCHSTATE_DISARMED,
   COUNTDOWN_MAX,
   0,
   0,


}

void on_button() {
  const unsigned long now = millis();
  switch (sketch.launch_state) {
    case LAUNCHSTATE_ARMED:
      change_state(LAUNCHSTATE_COUNTDOWN);
      sketch.last_tick = now;
      break;
    case LAUNCHSTATE_FIRING:
    case LAUNCHSTATE_POST_FIRE:

typedef struct Sketch_t {
  uint8_t button_state;
  uint8_t launch_state;
  uint8_t pending_state;
  uint8_t countdown;
  uint8_t button_tripped;
  uint8_t vread_dropouts;
