Do you think it would be possible to do this on a Arduino

@william.61509 It’s very possible that it is, but this was done specifically for ESPHome, which is a Home Assistant integration for ESP32 devices. I don’t actually own any arduino devices, so I’m not entirely sure. That being said, the ESP32 devices are great and super cheap. I think you can get a 3 pack for like $15-$20 online! They are super useful, especially in this configuration with the stepper motors. I use this to power my automated blinds controllers in my house. I can use Google or HA to trigger my blinds to open and close on a time or with voice commands. It’s really neat!

Thanks for the work @piratetunagames. I found the script will miss several minutes per day, so I updated the script for compensating. At the same time I added an entity to calibrate the clock - by setting the displayed time and calculate the steps accordingly, so no need to manually tick hours and minutes.

esphome:
  name: flip-clock
  friendly_name: Flip Clock

esp32:
  board: esp32dev
  framework:
    type: arduino

# Enable logging
logger:

ota:
  - platform: esphome
    password: "<REDACTED>"

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "flip-clock Fallback Hotspot"
    password: "<REDACTED>"

captive_portal:

# Enable Home Assistant API
api:
  encryption:
    key: "<REDACTED>"

script:
  - id: flip
    then:
      - if:
          condition:
            lambda: return !id(flipping);
          then:
          - globals.set:
              id: flipping
              value: 'true'
          - lambda: |
              auto now = id(sntp_time).now();

              // Skip movement on the first run
              if (id(last_reported_time) == 0) {
                id(last_reported_time) = now.timestamp;
                return;
              }
              
              int time_diff = 0;

              // Normal operation after initial run
              if (now.timestamp < id(last_reported_time)) {
                // Handle rollover if time is earlier than last reported time
                int seconds_in_a_day = 86400;
                time_diff = round(((now.timestamp + seconds_in_a_day) - id(last_reported_time)) / 60.0);
              } else {
                // Normal time difference calculation
                time_diff = round((now.timestamp - id(last_reported_time)) / 60.0);
              }

              int total_steps = time_diff * 136;
              if (id(accumulated_error) > 0.5){
                total_steps += 1;
                id(accumulated_error) -= 1;
              }
              id(accumulated_error) += 4096.0/30.0 - 136;

              // Move the stepper motor for the required steps
              id(clock_stepper).report_position(0);
              id(clock_stepper).set_target(total_steps);

              // Save the current time as the last reported time
              id(last_reported_time) = now.timestamp;
              id(flipping) = false;
          - globals.set:
              id: flipping
              value: 'false'

time:
  - platform: sntp
    id: sntp_time
    timezone: ${timezone}
    on_time:
      - cron: '0 * * * * *'
        then:
          - script.execute:
              id: flip

datetime:
  - platform: template
    type: time
    name: Calibration
    id: calibration
    lambda: "return ESPTime::from_epoch_local(id(last_reported_time));"
    set_action:
      - lambda: |
          auto now = id(sntp_time).now();
          int now_time = now.hour*3600+now.minute*60+now.second;
          int now_date = now.timestamp - now_time;
          int cali_time = x.hour*3600 + x.minute*60;
          if(cali_time > now_time)
            cali_time -= 86400;
          id(last_reported_time) = now_date + cali_time;
      - script.execute:
          id: flip

stepper:
  - platform: uln2003
    id: clock_stepper
    pin_a: 16
    pin_b: 17
    pin_c: 5
    pin_d: 18
    max_speed: $spin_speed steps/s
    step_mode: HALF_STEP
    sleep_when_done: True
    acceleration: 400 steps/s^2

# Variables to track last reported time and steps
globals:
  - id: last_reported_time
    type: int
    restore_value: yes
    initial_value: '0'
  - id: flipping
    type: bool
    restore_value: no
    initial_value: 'false'
  - id: accumulated_error
    type: float
    restore_value: no
    initial_value: "0"

substitutions:
  spin_speed: "900"
  timezone: "America/Los_Angeles"