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-- Saucier’s Sentinel README --

      (^ . ^)  welcome!

Saucier’s Sentinel — A Hot Process Timer

A chef‑friendly IoT device that monitors a 10‑minute hot‑process cycle for sauce making.
It reads a K‑type thermocouple, calculates the local boiling point from air pressure,
and alerts the chef with a playful OLED UI, LED blinks, Philips Hue bulbs, and Wemo smart plugs.

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Features

• Precise temperature monitoring** using a MAX6675 K‑type thermocouple
• Local boiling‑point calculation** using real‑time pressure from a BME280
• Chef‑friendly OLED UI** with animations, progress bar, and alert screens
• Smart kitchen integration**
• Philips Hue bulbs (blue = too cold, red = too hot)
• Wemo smart plugs (radio alert + stove cutoff)
• Single‑button interface**
• Short press -> start
• Long press -> cancel
• Stable state machine** for stable, predictable behavior
• Custom 3D‑printed enclosure** with slanted front, big easy-to-hit button and OLED window

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System Architecture

loop() ├── readSensors() ├── updateButtons() ├── runStateMachine() ├── updateAlerts() ├── updateLED() └── updateDisplay()

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Hardware

• Particle Photon 2**
• MAX6675 thermocouple amplifier**
• K‑type thermocouple probe**
• BME280 pressure + humidity sensor**
• 128×64 SSD1306 OLED (I²C)**
• Wemo smart plugs**
• Philips Hue bulbs**
• Custom 3D‑printed enclosure**

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Pinout

Component	Pin
Button	D6
LED	D7
Thermocouple CS	D5
Thermocouple SCK	D4
Thermocouple MISO	D3
OLED SDA	D0
OLED SCL	D1
BME280 SDA	D0
BME280 SCL	D1

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Local Boiling Point Calculation
(Clausius‑Clapeyron equation)

float calcBoilingPointC(float pressPA) {
    float pressHPA = pressPA / 100.0;
    float L  = 40650.0;
    float R  = 8.314;
    float T0 = 373.15;
    float P0 = 1013.25;

    float invT = (1.0 / T0) - (logf(pressHPA / P0) * R / L);
    return (1.0 / invT) - 273.15;
}

case SCREEN_CYCLE_IN_PROGRESS:
    if (cycleTimer.isTimerReady()) {
        currentScreen = SCREEN_SUCCESS;
        break;
    }
    if (tempF < TEMP_SAFE_LOW)  currentScreen = SCREEN_ALERT_LOW;
    if (tempF > TEMP_SAFE_HIGH) currentScreen = SCREEN_ALERT_HIGH;
    if (wasCancelHeld()) {
        cancelTimer.startTimer(CANCEL_MS);
        currentScreen = SCREEN_CANCELLING;
    }
    break;

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State Machine Core

case SCREEN_CYCLE_IN_PROGRESS:
    if (cycleTimer.isTimerReady()) {
        currentScreen = SCREEN_SUCCESS;
        break;
    }
    if (tempF < TEMP_SAFE_LOW)  currentScreen = SCREEN_ALERT_LOW;
    if (tempF > TEMP_SAFE_HIGH) currentScreen = SCREEN_ALERT_HIGH;
    if (wasCancelHeld()) {
        cancelTimer.startTimer(CANCEL_MS);
        currentScreen = SCREEN_CANCELLING;
    }
    break;

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OLED UI

Animated steam on loading screen

Big friendly temperature banner

Progress bar during cycle

Shiver animation (too cold)

Flame flicker (too hot)

Spinner animation (cancelling)

Sparkle animation (success)

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Enclosure

Designed in Onshape with:

Slanted ergonomic front

OLED window

Button recess

Thermocouple exit port

Internal mounting bosses

Smooth face blends and fillets

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Gallery

Enclosure files
(SaucemakersSentinel/Sentinel_IoT_device/enclosure/)

Internal layout
(SaucemakersSentinel/Sentinel_IoT_device/docs/Temp_monitor_device_fritzing_bb.png)
(SaucemakersSentinel/Sentinel_IoT_device/docs/Temp_monitor_device_fritzing_schem.png)

OLED UI photos
(SaucemakersSentinel/Sentinel_IoT_device/images/OLED_display.png)
(SaucemakersSentinel/Sentinel_IoT_device/images/OLED_Temp_Low.MOV)
(SaucemakersSentinel/Sentinel_IoT_device/images/OLED_complete.MOV)

Thermocouple in pot
(SaucemakersSentinel/Sentinel_IoT_device/images/Habanero_sauce.png)

Final assembled device 
(SaucemakersSentinel/Sentinel_IoT_device/images/device_with_active_screen_front.jpg)

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Files

/src — firmware

/enclosure — STLs

/images — photos + renders

/docs — diagrams + schematics

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Why This Exists
This project was created for a very special emerging hot‑sauce chef
who needed a reliable, friendly, and scientifically accurate way
to monitor the hot‑process cycle.

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License
MIT License — enjoy, remix, and cook boldly.

Project write‑up on Hackster.io:
https://www.hackster.io/melatova/saucier-s-sentinel-hot-process-timer-f0ca6f

[![Hackster Project](https://img.shields.io/badge/Hackster-Project-blue)](https://www.hackster.io/melatova/saucier-s-sentinel-hot-process-timer-f0ca6f)