nBack watchapp – ANDRWJ.COM

nBack is an ultra-precise, multimodal cognitive working memory training application designed exclusively for Pebble Time 2 (Emery Platform). It harnesses the full capabilities of Emery’s hardware—200×228 64-color Sharp MIP LCD, capacitive touchscreen, tactile 4-button input, and built-in raw tone generator—to deliver rigorous Dual, Triple, and Multi-modal n-Back challenges conforming to modern cognitive science standards.

Metadata & Author

Version: v1.99.100
Build Date: 2026-09-07
Developer: A.J (andrwj@gmail.com)
AppStore: https://apps.repebble.com/0fa107ae30f643e2b551a71b

Key Features

Multi-Modal Stimuli:
- Position (3×3 Grid spatial coordinate memory)
- Color (6-Color distinct palette recognition)
- Shape (10 Distinct geometric primitives rendered via GContext)
- Number (1–9 Digit recall)
- Letter (8-Letter phonetic working memory)
- Vibration (Haptic pulse pattern matching)
- Audio (26-Letter A–Z International Morse code audio tone synthesis)
Adaptive Auto-Leveling: Automatically adjusts n-Back difficulty (n=1 to n=7) based on real-time performance thresholds.
Strict FSM Architecture: Zero state-bypass execution model guaranteeing lifecycle purity and instant responsiveness.
OPFS Local Sandbox: Training session histories and player profiles are saved inside the mobile browser’s Origin Private File System (OPFS) for private, robust local storage.

Audio Stimulus: Morse Code Sound Patterns

The audio modality utilizes the Pebble Time 2 (Emery) built-in speaker to synthesize International Morse Code for all 26 English letters (A–Z).

Sound Synthesis Parameters

Parameter	Specification	Description
Tone Pitch	523 Hz (MIDI Note 72, C5)	Pure Sine Wave (`SpeakerWaveformSine`)
Dot (`·`) Duration	65 ms	Short tone pulse
Dash (`—`) Duration	195 ms	Long tone pulse (3 \times \text{Dot})
Element Gap	50 ms	Silence between dots and dashes within a letter
Volume	85 / 100	Internal raw tone generator

Letter-to-Sound Pattern Mapping (A–Z)

Letter	Sound Pattern	Letter	Sound Pattern	Letter	Sound Pattern	Letter	Sound Pattern
A	`· —`	H	`· · · ·`	O	`— — —`	V	`· · · —`
B	`— · · ·`	I	`· ·`	P	`· — — ·`	W	`· — —`
C	`— · — ·`	J	`· — — —`	Q	`— — · —`	X	`— · · —`
D	`— · ·`	K	`— · —`	R	`· — ·`	Y	`— · — —`
E	`·`	L	`· — · ·`	S	`· · ·`	Z	`— — · ·`
F	`· · — ·`	M	`— —`	T	`—`
G	`— — ·`	N	`— ·`	U	`· · —`

Target Platform Specifications

Specification	Details
Target Device	Pebble Time 2 (Emery)
Display	200 × 228 pixels, 64-Color MIP LCD
Sensors & I/O	4 Physical Buttons, Capacitive Touchscreen, 3D Accelerometer, Built-in Speaker
RAM Footprint	~27 KB (Well below the 32 KB threshold)