7 Segment Clock, v3.2C, 12-Hour

7 segment 3D printed 12-hour clock based on v3.0 mechanical counter. Uses three stepper motors with an Arduino Uno and a DS3231 RTC to maintain and display time. Uses some components from v3.0 while also introducing new parts specific to the clock. 
 

If you found this interesting or useful, please consider supporting my work at: https://buymeacoffee.com/Flower3D. 
 

See Video Tutorial Part 1 Here:

See Video Tutorial Part 2 Here: 

This clock is based on the 7 Segment mechanical counter v3.0: https://www.printables.com/model/959686-7-segment-mechanical-counter-version-30-ratchet-fo/

3D printed parts & quantities required for this clock build:

(1) - BODY_MINUTES_v3.2C   

(1) - CASE_BACK_MINUTES_v3.2C (updated 5/16/25; previous STL was upside down)

(1) - BODY_12-HOUR_v3.2C  

(1) - CASE_BACK_12-HOUR_v3.2C

(3) - MID_PLATE_v3.2C 

(2) - BACK_PLATE_SINGLE_v3.2C

(1) - BACK_PLATE_12-HOUR_v3.2C

(1) - SEG_PLATE_HOUR_TENS_v3.2C

(3) - SEG_PLATE_v3.2

(3) - DRIVEN_GEAR_v3.2C

(3) - DRIVE_GEAR_v3.2C     

(1) - CAM_HOUR_CARRY_v3.2C    

(8) - STAND-OFF_SCREW_v3.2C   

(14) - SCREW_v3.0   

(2) - COLON_SCREW_v3.2C 

(1) - RTC-BRACKET_v3.2C     

(3) - HOME_POSITION_SPRING_v3.2C    

(3) - TIMING_GEAR_No1_v3.0    

(3) - TIMING_GEAR_No2_v3.0  

(1) - CAM_A1-6_v3.2C

(1) - CAM_A2-6_v3.2C

(1) - CAM_B1-6_v3.2C

(1) - CAM_B2-6_v3.2C

(1) - CAM_C1-6_v3.2C

(1) - CAM_C2-6_v3.2C

(1) - CAM_D2-6_v3.2C    

(2) - CAM_A1_v3.0

(2) - CAM_A2_v3.0

(2) - CAM_B1_v3.0

(2) - CAM_B2_v3.0

(2) - CAM_C1_v3.0

(2) - CAM_C2_v3.0

(3) - CAM_D1_v3.2C 

(2) - CAM_D2_v3.2C     

(6) - SEG_A_v3.0

(6) - SEG_B_v3.0

(6) - SEG_C_v3.0

(3) - SEG_D_v3.1

(1) - SEG_HOUR_TENS_v3.2C     - OR -     SEG_HOUR_TENS_v3.2C_withRafts   (if needed, helps prevent warping. Rafts will need to be cut off)

Optional 3D printed parts & quantities:

(1) - BODY_MINUTES_v3.2C_TEST-PRINT (reduced-size practice-print to test fitment and tolerance before committing to the full-scale large print)

(1) - BODY_12-HOUR_v3.2C_TEST-PRINT (reduced-size practice-print to test fitment and tolerance before committing to the full-scale large print)

Non-3D printed parts & quantities required for this clock build:

(1) - Arduino UNO 

(3) - Stepper Motor, 28BYJ-48, 12VDC 

(3) - Stepper Driver, ULN2003 

(3) - Limit Switch (10.6mm x 20mm), 16mm Straight Actuator 

(1) - Real-Time Clock Module, DS3231 

(1) - Barrel Connector M (5.5mm x 2.1mm) 

(1) - Barrel Connector F (5.5mm x 2.1mm) 

(1) - Power Supply, AC-DC, 9VDC, 2A, (with 5.5mm x 2.1mm barrel conn.)  

(X) - Dupont Wires, various lengths & pins (MF, FF, MM, 10cm, 20cm, & 30cm) 

(6) - M3 x 6mm (2/ stepper motor)

(6) - M3 x 8mm (2/ stepper driver) 

(2) - M3 x 12mm (2/ UNO) 

        - OR      (14) - M3 x 12mm (for all M3 Locations; replaces 3 lines above) 

(2) - M2 x 8mm (2/ RTC to bracket) 

(4) - M2 x 10mm (2/ limit switch not shared with RTC bracket) 

(2) - M2 x 12mm (2/ limit switch shared with RTC bracket) 

         - OR      (8) -  M2 x 12mm (for all M2 Locations; replaces 3 lines above) 

(14) - M3 Nuts

(8) - M2 Nuts

(4) - Rubber Band, 60mm (D-Segment & Hours Tens Digit) 

(3) - Rubber Band, 100mm (A, B, & C Segments) 

Printer Settings/Profile: 

Bambu Studio Profile:

0.20mm Standard @BBL X1C 

General Settings: 

Material:  PLA
Layer Height:  0.2mm
Infill:  100%
Supports:  No

Based on a 0.4mm nozzle

Arduino Files Included:

• Arduino script (copy and paste into Arduino IDE):  
  • 7-Seg_v3.2C_v1.0.txt - (5/6/25; original version, includes comments)
  • 7-Seg_v3.2C_v1.1.txt - (5/13/25; latest version, updated indentation, removed duplicate operations, and improved code structure. This version does an initial sweep setting all digits to their home positions first and then does a second pass to set the time. Otherwise operates in the same general fashion as v1.0 requiring the same user inputs as shown in video part 2)
  • {future revision} - (to include button for time setting)
• Stepper library:  Stepper.zip
• RTC library:  DS3231.zip

Library Sources:

• Stepper - http://www.arduino.cc/en/Reference/Stepper
• DS3231 - http://www.RinkyDinkElectronics.com/