RoboClock

Turning the EEZYbotARM into a time telling machine!

Overview

This project attempts to use the EEZYbotARM designed by daGHIZmo (Original License) to keep time by arranging a set of 3D printed numbers in the correct order.

The clock consists of three parts...

• A Podium
  • A stand that supports the digits used to tell the current time
• An Inventory
  • A chainlink / sprocket / tray system that stores all of the excess digits
  • See Inventory.h for the arduino code
  • See /Parts/Inventory for parts (stl) or Thingiverse
• The EEZYbot Robot Arm (see Arm.h)
  • Responsible for moving the physical digits between the inventory and podium
  • See Arm.h for the arduino code
  • See Thingiverse for parts
  • With modified gripper assembly at
    • /Parts/GripperModified
    • or Thingiverse

Every 5 minutes the arm rearranges/replaces the numbers on the podium to reflect the current time. Depending on how many numbers need changing, the entire update cycle can last anywhere from 45 to 90 secs.

How To

Check out the instructables for a detailed guide to building your own

• Download, Slice, Print and Assemble the EEZYbotARM
• Download, Slice, Print and Assemble the RoboClock parts
• Pro Tip 💡: Before printing the entire 18 segment chain, print a few segments of the chain and adjust the height of Chain_Spacer.stl to make sure your chain has the desired tolerances. It should rotate freely with minimal lateral sag.
• Mount parts to surface
• Upload the meastro_settings.txt to the Micro Maestro using the Maestro software from Pololu
• Tweak the sequences if needed to ensure the pre-programmed sequences move the to the correct locations
• Wire up the electronics / circuit
• Download the arduino sketch and dependencies using the IDE's library manager
• Enter your wifi's credentials in arduino_secrets.h (if using the MKR1000 Wifi)
• Compile & Upload the code to the arduino
• Arrange the numbers on the chain in the anti-clockwise order (0,0,1,1,1,2,2,3,3,4,4,5,5,5,6,7,8,9)
• Place the remaining zero on the last podium slot ( _ , _ , _ , 0 )
• Plug in and watch it probably not work...
• Tune the maestro sequences until things work

Arduino SketchBooks

• RoboClock_Seeeduino (Tested and working)
  • Includes 3 custom libraries
    • Clock.h
      • Main orchestrator between Inventory and Arm
      • Responsible for determining operations to acheive a certain clock state
      • Repsonsible for the synchronous execution of those operations to achive the desired clock state
    • Arm.h
      • Responsible for running pre-recorded subroutines on the Micro Maestro
    • Inventory.h
      • Responsible for presenting requested digits (or empty slots) via the stepper motor diver.
      • Responsible for maintaining an inventory state (what digit resides in each slot).
• RoboClock_MKR1000 (Tested and working)
  • Uses the Arduino MKR1000 Wifi
  • The same Clock, Arm and Inventory libraries as above with the addition of networked time sync via NTP
  • Also includes a few simple functions to convert UTC to your timezone (while protecting for daylight savings time when appropriate) (not fully tested)
  • Two operation modes (set the Inventory.usingSensors bool flag appropriately)
    • Using Hall Effect Chain Sensors (closes the inventory loop to create a much more robust inventory system)
    • Not using Chain Sensors (the chain system may bind and cause the stepper motor to lose steps, at which point the system can't recover)

Arduino Libraries / Dependencies

• PololuMaestro
• CheapStepper
• Seeeduino Specific
  • Time & TimeLib
• MKR1000 Specific
  • RTCZero

Hardware ( ~150 USD if you need to purchase everything listed )

• Pololu Servo Controller (Micro Maestro) (requires 5v serial)
• 4x MG90S Servos
• 28BYJ-48 5V DC Stepper Motor
• ULN2003A Stepper Driver
• MKR1000 or Seeeduino rev2.21 (used for its 5v gpio pins)
• Voltage Level Shifter (if using 3.3v board like the Arduino MKR1000 Wifi)
• 5v ~3 Amp Power Supply
• 608ZZ Bearing
• Assorted M3-M5 Nuts and Bolts (lock nuts recommended)
• Jumper Wires and Breadboard
• 3x1mm Magnets
• A3144 Hall Effect Sensors (optional but recommended)

Tools

• 3D Printer
• Windows Comp with USB for Pololu Meastro Software
• Arduino IDE
• M3-M5 Allen Keys
• Pliers
• Wood Screws and Screw Driver
• A surface to mount everything to (a recycled bookshelf works well)
• Superglue If using the chain sensor
• Soldering Iron
• 2x Capacitors (0.1 uF)
• 2x Resistors (10k Ohms)

Electronics / Circuit Diagram

Variants

• Seeeduino Controller (done)
  • Pros:
    • Makes development simple. Has 5v serial that makes interfacing with the micro maestro easy.
  • Downsides
    • No network for time sync / management
    • Limited RAM (we're currently at ~85% memory and getting warnings on the Arduino IDE)
• Arduino MKR1000 (waiting for logic level shifter)
  • Pros:
    • Wifi built in for time sync / management
    • Faster & more RAM
  • Cons:
    • 3.3v architecture requires the use of a 3.3v <-> 5v Logic Level Shifter for communication with the Micro Maestro
• TODO: Raspberry Pi Zero W (not started, 3.3v gpio as well)

Notes & References

• Arduino
  • Writing a Library
• MKR1000
  • Additional Serial Ports - Example Code
  • Additional Serial Ports - Forum
  • WiFiRTC Example
• Micro Maestro Documentation
• Unipolar -> Bipolar 28BYJ Conversion
• Raspberry Pi
  • 28BYJ Stepper Motor & ULN2003 Driver

3D Printed Parts

• EEZYbotARM MRK 1 designed by daGHIZmo (Original License)
• RoboClock