Project 22: Capstone Program - Six Full System Builds

Design six full-stack Cardputer product builds, each with architecture diagram, resource budget, failure modes, and performance targets.

Quick Reference

Attribute Value
Difficulty Master
Time Estimate 1-3 months
Main Programming Language C
Alternative Programming Languages C++, Rust
Coolness Level Level 5
Business Potential Level 5
Prerequisites Prior projects P09-P21
Key Topics Full-system architecture, budgeting, failure design, performance governance

1. Learning Objectives

  1. Convert requirements into architecture and measurable constraints.
  2. Manage cross-domain integration risk.
  3. Build failure-aware designs before implementation.
  4. Define production-grade performance targets.

2. Capstone Build Set (Required)

2.1 Pocket Dev Terminal (USB + WiFi + File Browser)

[Keyboard] -> [Shell UI] -> [Command Engine]
                          -> [Wi-Fi Client]
                          -> [File Browser]
                          -> [USB CDC]
  • Resource budget: Flash 2.0MB, RAM 180KB + 512KB PSRAM
  • Failure modes: SD mount fail, USB drop, network timeout
  • Performance targets: command echo p95 < 60ms

2.2 IR Universal OS with Protocol Auto-Detection

[IR RX] -> [Pulse Decoder] -> [Protocol Classifier] -> [IR TX]
  • Resource budget: Flash 1.8MB, RAM 140KB + 256KB PSRAM
  • Failure modes: ambiguous protocol, replay drift
  • Performance targets: decode confidence > 95%

2.3 Portable Audio Analyzer

[Mic] -> [I2S DMA] -> [FFT Pipeline] -> [Spectrum UI]
  • Resource budget: Flash 1.9MB, RAM 220KB + 1MB PSRAM
  • Failure modes: buffer underrun, clipping, SD stalls
  • Performance targets: 1024 FFT >= 60fps

2.4 Wi-Fi Diagnostic Tool (authorized environments)

[Radio Manager] -> [Promisc Stats] -> [TCP Probe] -> [Export UI]
  • Resource budget: Flash 2.2MB, RAM 200KB + 768KB PSRAM
  • Failure modes: packet overflow, reconnect storm
  • Performance targets: channel cycle <= 1.2s

2.5 Data Logger with OTA Dashboard

[Sensors] -> [Log Engine] -> [Uploader]
                       -> [OTA Lifecycle]
  • Resource budget: Flash 2.4MB, RAM 190KB + 512KB PSRAM
  • Failure modes: power loss mid-write, OTA interrupt
  • Performance targets: zero corruption in injected tests

2.6 Secure Field Notes Device

[UI] -> [Notes Engine] -> [Encrypted Storage] -> [TLS Sync]
  • Resource budget: Flash 2.3MB, RAM 210KB + 512KB PSRAM
  • Failure modes: key corruption, cert failure, rollback attempt
  • Performance targets: note save p95 < 120ms

3. Core Question

“Can I repeatedly ship integrated embedded systems that meet strict reliability, security, and performance expectations?”

4. Implementation Strategy

  1. Select one capstone as primary implementation target.
  2. Freeze architecture and budget contracts.
  3. Implement by subsystem with telemetry from day one.
  4. Run failure-injection drills before declaring completeness.

5. Test and Validation

  • Resource budget enforcement per build.
  • Failure-mode simulation suite.
  • Performance target dashboard with p95 gates.

6. Common Pitfalls

  • Scope creep without budget guardrails.
  • Late performance instrumentation.
  • Missing failure drills for “rare” edge cases.

7. Completion Criteria

  • All six capstone dossiers are fully documented.
  • One capstone is implemented to prototype quality.
  • Resource/failure/performance evidence is included.