# 🌟 UHX Walkthrough: From UHT to SDR
This page takes you on a step-by-step journey through the Universal Hex (UHX) modeling pipeline using a real-world example: a **Smart Thermostat**.
We’ll trace how to:
1. Define its **semantic identity** (UHT)
2. Connect it to other system components (**UHR**)
3. Model its state behavior (**UHS**)
4. Derive a structured, self-describing requirement (**SDR**)
---
## 🔍 1. UHT — Identity of the Smart Thermostat
The thermostat is a [[40 00 00 00 - Man-made or Synthetic|man-made]], [[04 00 00 00 - Perceptible|perceptible]], logic-driven, behavior-guiding interface that interacts with humans and operates autonomously.
### UHT Traits
```yaml
- 2: Man-made
- 6: Perceptible
- 10: Emits output
- 11: Processes logic
- 12: Transforms internal state
- 13: Interacts with humans directly
- 15: Autonomous in function
- 21: Behavior-guiding
```
### UHT Code
```text
UHT: 42 FA 00 A0
```
---
## 🔗 2. UHR — Semantic Relationships
The thermostat:
- Receives temperature input from a sensor
- Controls an HVAC system
- Is governed by building policies
### UHR Links
```yaml
- from: Temperature Sensor
to: Thermostat
uhr: "C1" # Feeds →
- from: Thermostat
to: HVAC System
uhr: "C1" # Feeds →
- from: Building Policy
to: Thermostat
uhr: "A5" # Constrains →
```
Each link encodes not just direction, but **meaningful causality or control**.
---
## ⏱️ 3. UHS — Behavior Over Time
### States:
```yaml
- Idle: 42F20000 # Passive, structural
- Monitoring: 42FA0000 # Emits output, logic active
- Adjusting: 42FA00A0 # + Behavior-guiding, human interaction
```
### Transitions:
```yaml
- Idle → Monitoring
trigger: System power-on
via: C1
- Monitoring → Adjusting
trigger: Temperature outside target
via: C1
- Adjusting → Monitoring
trigger: Desired temperature reached
via: C1
```
You now have an explainable **semantic state machine**.
---
## 🔨 4. SDR — Self-Describing Requirement
```yaml
id: SDR-THERM-01
name: "Autonomous Smart Thermostat"
description: "A human-facing logic controller that regulates temperature autonomously."
must_have_traits:
- 2 # Man-made
- 6 # Perceptible
- 10 # Emits output
- 11 # Processes logic
- 13 # Interacts with humans
- 15 # Autonomous
- 21 # Behavior-guiding
required_links:
- relation: "Feeds →"
uhr: "C1"
target_must_have: [10] # HVAC must emit output
- relation: "Constrained by"
uhr: "A5"
source_must_have: [28] # Must be governed
states:
- Idle
- Monitoring
- Adjusting
delta_expected:
- from: Monitoring
to: Adjusting
add: [21] # Must gain behavior-guiding trait
parameters:
control_latency_s:
max: 3
temperature_range_C:
min: 18
max: 26
```
---
## 🚀 Summary
|Step|UHX Layer|Output|
|---|---|---|
|Identity|UHT|Traits + 32-bit code|
|Structure|UHR|Causal, symbolic, governed links|
|Behavior|UHS|States + transitions with logic|
|Spec|SDR|Testable, portable, explainable spec|
This pipeline models **what the system is**, **how it behaves**, and **what it must satisfy** — in a unified, semantic format.
Would you like similar walkthroughs for systems like a smart door lock, drone, or EV battery controller?