Splitflap display v1

Split-Flap Display

Arduino firmware and KiCad hardware files for a single split-flap display module.

Contents

• split_flap_module/split_flap_module.ino - Arduino module controller firmware
• splitflap_display_v1/ - KiCad schematic, PCB, and project files

Firmware

The firmware is written for an Arduino-compatible AVR board and a step/dir driver:

• STEP_PIN = 2
• DIR_PIN = 3
• HOME_PIN = 4 with INPUT_PULLUP
• 200 step/rev motor
• 1/8 microstepping
• 14 tooth pinion driving a 26 tooth pulley
• 52 flap positions

Compile with Arduino CLI:

arduino-cli compile --fqbn arduino:avr:uno split_flap_module

Serial Control

Open serial at 115200 baud.

Useful commands:

help
status
sensor
diag
mechanics
chars
home
goto <0-51>
show <char|space>
jog <steps>
speed [microseconds]
mark <0-51>
demo on|off|once
stop

The character map is:

0      space
1-26   A-Z
27-36  0-9
37-45  . , : ! ? - # $ +
46-51  blanks

Calibration

After homing, if the physical flap shown is not logical position 0, use mark. For example, if the module is showing C and the table uses space=0, A=1, B=2, C=3:

mark 3

Calibration is saved to EEPROM automatically.

Demo Mode

For a single module, demo mode cycles through a simple readable sequence:

demo on

It spells SPLIT FLAP, shows the numerals, and then punctuation with blank pauses between sections.

Hardware

The KiCad source files are tracked. Gerbers, drill files, zip archives, lock files, and local history are ignored because they can be regenerated from the KiCad project.