Project Files of LOLIN S2 Mini Library for Proteus: Fire and Gas Alarm, Wi-Fi

LOLIN S2 MINI LIBRARY FOR PROTEUS - V1.0 (YOUR ESP32-S2 SKETCH ON THE S2 MINI, WI-FI, A KITCHEN FIRE AND GAS ALARM)
Designed by The Engineering Projects
www.TheEngineeringProjects.com

IMPORTANT LINKS
Article (read it first - pictures, step by step, every feature explained):
  https://www.theengineeringprojects.com/2026/10/lolin-s2-mini-library-for-proteus.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/lolin-s2-mini-proteus-library
The demo's sensors are our libraries (included) - their articles:
  https://www.theengineeringprojects.com/2026/10/flame-sensor-library-for-proteus-v2-0.html
  https://www.theengineeringprojects.com/2026/10/mq-gas-sensor-library-for-proteus-v1-0.html
The other small Wi-Fi boards of the series:
  https://www.theengineeringprojects.com/2026/10/wemos-d1-mini-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/xiao-esp32-c3-library-for-proteus.html
The laptop and the phone:
  https://www.theengineeringprojects.com/2026/10/laptop-wifi-monitor-library-for-proteus.html
  https://www.theengineeringprojects.com/2026/10/mobile-wifi-monitor-library-for-proteus.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
LOLIN-S2-Mini-TEP-v1.0/
|-- Proteus Library Files/
|   |-- TEPFLAME.LIB                                    213.2 KB   the flame sensor (demo), to LIBRARY
|   |-- TEPLAPTOP.LIB                                    39.5 KB   the laptop (demo), to LIBRARY
|   |-- TEPMOBILE.LIB                                    13.1 KB   the phone (demo), to LIBRARY
|   |-- TEPMQGAS.LIB                                    553.0 KB   the MQ gas sensors (demo), to LIBRARY
|   |-- TEPS2MINI.LIB                                    34.0 KB   the LOLIN S2 Mini, to LIBRARY
|-- Proteus Model Files/
|   |-- TEPFLAME.DLL                                    389.5 KB   the flame sensor, to MODELS
|   |-- TEPMQGAS.DLL                                    328.5 KB   the MQ gas sensors, to MODELS
|   |-- TEPNET.DLL                                       2.46 MB   the board + monitors + network, to MODELS
|-- Arduino Code/
|   |-- S2Mini_Kitchen_Alarm/S2Mini_Kitchen_Alarm.ino     8.0 KB   the demo sketch
|   |-- TEP Boards for Proteus/hardware/                707.7 KB   the Arduino IDE add-on 1.25.0 (166 files)
|-- Proteus Simulation/
|   |-- LOLIN-S2-Mini-Kitchen-Alarm.pdsprj               31.6 KB   the demo: a kitchen fire and gas alarm
|   |-- S2Mini_Kitchen_Alarm.hex                         68.5 KB   the demo sketch (U1)
|   |-- TEPFLAME.DLL                                    389.5 KB   copy of the model
|   |-- TEPMQGAS.DLL                                    328.5 KB   copy of the model
|   |-- TEPNET.DLL                                       2.46 MB   copy of the model
|-- README.txt                                          ~14.8 KB   this file
Total: 7.96 MB (unzipped). The source code of the models is not included.

WHAT IS IT?
Proteus 8 has no ESP32-S2 processor model (the S2's Xtensa LX7 core is not in Proteus), so this is NOT a real ESP32-S2
chip. It is WEMOS / LOLIN's S2 Mini - the small blue board with the ESP32-S2FN4R2, the USB-C port, the 0 (BOOT) and RST
buttons, the blue LED and two rows of pins on each long side - that runs YOUR ESP32-S2 Arduino sketch in Proteus:
  * You write a normal S2 Mini sketch (the S2's GPIO numbers 1 .. 18, 21, 33 .. 40, LED_BUILTIN = 15, analogRead 0-4095,
    analogReadMilliVolts, analogWrite, ledcWrite, attachInterrupt, Wire on 33 / 35, SPI on 7 / 9 / 11 / 12, WiFi,
    WebServer, HTTPClient, ESPmDNS ...) and compile it in the Arduino IDE with our board package \"TEP Boards for
    Proteus\" 1.25.0 (in Arduino Code - see INSTALLATION).
  * Inside the board, Proteus's own ATmega2560 model runs the compiled sketch at 16 MHz; our model (TEPNET.DLL) wraps
    it: the 32 pins with their GPIO numbers, the 0 button (GPIO0), RST, the PWR LED, the blue LED, the built-in serial
    monitor and the Wi-Fi radio.
  * Wi-Fi: a virtual router (TEP-WiFi, password 12345678 - the WIFISSID / WIFIPASS properties) with DHCP (192.168.1.101
    for U1), a scan list, RSSI, mDNS names, NTP time, TCP and UDP between all the TEP Wi-Fi parts in the design.
The board is drawn as the real one seen from above, turned so the USB-C port is on the left: 0 and RST beside it, the
ESP32-S2 with its crystal, the PWR and blue LEDs, the PCB antenna on the right and the 4 x 8 pins (top outer: 3V3 12 11
9 7 5 3 EN; top inner: 14 13 10 8 6 4 2 1; bottom inner: 15 GND 17 21 34 36 38 40; bottom outer: VBUS GND 16 18 33 35 37
39). The inner rows are drawn half a pin step along (on the real board they sit in line with the outer rows) so that
every pin has its own wire.
TEP additions: the PCB antenna changes colour with the Wi-Fi (gold not joined, green on Wi-Fi, orange sending, cyan
receiving), the PANEL pad (or the chip) opens the board's panel, the USB-C port opens the serial monitor.
Limits (say them before you start): 16 MHz, 8 KB of RAM (the real S2: 240 MHz, 320 KB plus 2 MB of PSRAM), 256 KB of
flash, int is 16 bits (use long / int32_t for big numbers), no FreeRTOS tasks, no native USB (Serial is the board's
monitor), no ESP-IDF, no real TLS, no soft AP. The ESP32-S2 has no Bluetooth, and neither has ours. See MODEL SCOPE AND
LIMITS.

ONE DEVICE (search "LOLIN" or "S2 MINI" in Pick Devices):
  LOLIN S2 MINI  "LOLIN S2 Mini" V1.0 (Microprocessor ICs > ESP32 Boards), prefix U, model TEPNET.DLL. The panel (a TEP
  pop-up window; the PANEL pad opens it): Wi-Fi (a phone: OPEN ESP32 PAGE, the router's list), Pins (every pin live),
  Test, Settings, Help. The serial monitor (115200 baud) has Monitor, Plotter and Board tabs (the Board tab: the LEDs,
  0, RST, every pin). Like every TEP window it has no Windows title bar.
The same TEPNET.DLL also runs our other Wi-Fi boards and the Laptop / Mobile WiFi Monitors; it replaces any older
TEPNET.DLL (keep only this newest one in MODELS).

TEST STATUS
V1.0: verified in Proteus 8.5 on 26 Oct 2026 with the demo project as shipped. What the Proteus run showed:
* LOLIN-S2-Mini-Kitchen-Alarm: the monitor printed "Connecting to TEP-WiFi", "Alarm page: http://192.168.1.101/",
  "MQ-5 warming up ...", "MQ-5 calibrated in clean air: R0 = 0.922 kOhm" and "Armed: watching for flames and gas",
  then "IR 5 %  LPG 1 ppm  CH4 1 ppm  AO 0.69 V  state SAFE" every 2 s; the PWR and blue LEDs on, the antenna green
  on Wi-Fi; the board's panel: on TEP-WiFi at 192.168.1.101.
* The laptop (192.168.1.21) opened http://192.168.1.101/json and the phone (192.168.1.41) http://192.168.1.101/
  (HTTP 200).
* Candle on the flame sensor's pop-up: ">> FIRE - flame detected (IR 72 %)", the ALARM LED on, the phone and the
  laptop: FIRE; None: ">> FLAME GONE" (the alarm stays on); RESET on the phone: "Reset (the web page)".
* LPG 1000 ppm on the MQ-5's pop-up: ">> GAS WARNING - LPG 528 ppm"; 5000 ppm: ">> GAS LEAK - LPG 2048 ppm", up to
  "LPG 4140 ppm  CH4 11204 ppm  AO 4.21 V  state GAS LEAK  ALARM"; VENTILATE: ">> GAS WARNING - LPG 1966 ppm",
  ">> CLEAN AIR - LPG 488 ppm"; RESET on the phone.
* About 43 s of simulation (the waits included), no errors, with both pop-ups, the panel, the monitor and both tools
  open.

INSTALLATION (about 3 minutes)
1. Close Proteus. Extract the WHOLE ZIP to a normal folder (e.g. Desktop).
2. Copy everything in "Proteus Library Files" to the LIBRARY folder of Proteus, for example:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\LIBRARY
   (on some PCs: C:\ProgramData\Labcenter Electronics\Proteus 8 Professional\LIBRARY). TEPS2MINI.LIB is the board; the
   others are the demo's parts: TEPFLAME.LIB, TEPMQGAS.LIB, TEPLAPTOP.LIB and TEPMOBILE.LIB.
3. Copy the DLLs from "Proteus Model Files" (TEPNET.DLL, TEPFLAME.DLL, TEPMQGAS.DLL) to the MODELS folder (...\Proteus 8
   Professional\MODELS) - replace an older TEPNET.DLL (this one is the first that knows the LOLIN S2 Mini).
4. Delete TEPS2MINI.IDX from the LIBRARY folder if it is there.
5. The Arduino IDE (only to compile your own sketches - the demo has its HEX file): copy the folder
   "Arduino Code\TEP Boards for Proteus\hardware" into your sketchbook folder (normally Documents\Arduino), so that
   Documents\Arduino\hardware\tep\avr\boards.txt exists (replace an older copy); restart the IDE. The Arduino AVR Boards
   platform must be installed (it comes with IDE 1.8.x; in IDE 2.x install "Arduino AVR Boards" from the Boards Manager
   once). Tools > Board > TEP Boards for Proteus > LOLIN S2 Mini (TEP Proteus). The demo needs no other library.
6. Start Proteus. In Pick Devices (P) search "LOLIN".

RUN THE DEMO
Keep the .hex file and the DLLs beside the project in "Proteus Simulation".
LOLIN-S2-Mini-Kitchen-Alarm.pdsprj - U1 the LOLIN S2 Mini (S2Mini_Kitchen_Alarm.hex) is a kitchen fire and gas alarm:
U2 = the flame sensor module, its A0 through a 100k / 200k divider (R1 / R2) to GPIO3; U3 = the MQ-5 gas sensor module
(LPG and natural gas), its AO through a 10k / 20k divider (R3 / R4) to GPIO5; D1 = the ALARM LED on GPIO12 (R5 220R).
PC1 the Laptop WiFi Monitor opens http://192.168.1.101/json, MOB1 the Mobile WiFi Monitor the page
http://192.168.1.101/. Both sensors are the Advance versions: each opens its pop-up window at Run.
Why the dividers: both modules run on 5 V (the MQ-5's heater needs it), so their analog outputs reach 5 V, and the
ESP32-S2's ADC reads 0 .. 3.3 V (its pins are not 5 V tolerant). A divider of 1 : 2 scales 5 V to 3.33 V; the sketch
multiplies the pin's voltage by 1.5. The flame divider is 100k / 200k because the flame module's A0 has a 10 k pull-up
(a 30 k load would pull it down by a quarter); the MQ-5's AO is the board's 1 k load resistor, so 10k / 20k is light
enough (the sketch takes RL as 1 k with 30 k across it: 0.968 k). The modules' D0 / DO outputs are not used (their
pull-ups go to 5 V); the sketch sets its own levels on the analog outputs.
The sketch: the flame module's A0 is 4.98 V with no infrared and 0.1 V at the most, so the IR level is (4.98 - A0) /
4.88 x 100 %; a fire is 45 % or more for 1 s (5 readings in a row). The MQ-5: Rs = RL x (5 V - AO) / AO; 5 s after the
start (the module's WARMUP is 3 s in the demo) the sketch measures R0 in clean air (Rs / R0 = 6.5 there, the
datasheet), then LPG = 80.897 x (Rs / R0) ^ -2.431 and methane = 177.65 x (Rs / R0) ^ -2.56 ppm (the MQ-5 curves of
MQUnifiedsensor). LPG 500 ppm = GAS WARNING (the ALARM LED blinks), 2000 ppm (about 10 % of the lower explosive limit) =
GAS LEAK. A fire or a leak latches the alarm (the ALARM LED on) until RESET; the blue LED is on while it is armed.
Press Run. The board joins TEP-WiFi, the MQ-5 warms up, "MQ-5 calibrated in clean air" and "Armed". On the flame
pop-up click Candle: FIRE, the ALARM LED lights, the page says FIRE; click None and RESET on the phone. On the MQ-5
pop-up click 1000 ppm (GAS WARNING), then 5000 ppm (GAS LEAK); VENTILATE brings the air back; RESET on the phone.
Closed a window? The USB-C port of the board opens the monitor, the PANEL pad the panel. The monitor (115200) prints
every event and a status line every 2 s and takes STATUS, RESET and CAL (R0 again, in clean air).

THE PINS (the label on the board, what it can do in the simulation)
  1 .. 6, 8, 10, 13, 14  GPIO, analogRead (A0 .. A9, A12, A13) 0 .. 4095 for 0 .. 3.3 V, PWM, interrupt
  7, 9, 11, 12           SPI SCK / MISO / MOSI / SS (GPIO too)
  33 / 35                Wire SDA / SCL (GPIO too)
  39 / 37                Serial2 TX / RX (GPIO too)
  15                     GPIO, the blue LED (LED_BUILTIN, lit when HIGH)
  16, 17, 18, 21, 34, 36, 38, 40  GPIO, PWM, interrupt
  0                      the 0 (BOOT) button (LOW when pressed; not on the header)
  EN                     the reset (the RST button)
  3V3, VBUS, GND         3.3 V (the logic), 5 V, ground

PROPERTIES (double-click the board > Edit Properties)
  PROGRAM   the sketch's HEX (Arduino IDE: Sketch > Export Compiled Binary with LOLIN S2 Mini (TEP Proteus))
  WIFISSID  the router in range (default TEP-WiFi);  WIFIPASS  its password (default 12345678)
  MONITOR   YES = the built-in serial monitor (Serial);  BAUD  its speed (115200, or AUTO)
  AUTOOPEN  YES = the monitor window opens at Run (the demo: YES)
  TIME      the clock for NTP: PC (the PC's clock) or YYYY-MM-DD HH:MM:SS in UTC
The IP address follows the part's number: U1 192.168.1.101, U2 .102 ...

TROUBLESHOOTING
* Nothing happens at Run: the HEX was not built with TEP Boards for Proteus - select LOLIN S2 Mini (TEP Proteus) and
  export again.
* The gas readings are far too high: R0 was measured during the warm-up or with gas in the air - type CAL in clean air.
* IR level about 25 % with no flame: the flame divider is too low (10k / 20k loads the module's 10 k pull-up) - use 100k
  / 200k as in the demo.
* analogRead returns 0: the pin has no ADC (33 .. 40 have none on the ESP32-S2) - use 1 .. 10, 13 or 14.
* The board stays off the network: the sketch's SSID / password differ from WIFISSID / WIFIPASS.
* An integer goes wrong above 32767: int is 16 bits on the hidden AVR - use long.
* The page shows old values: tap REFRESH (the monitors do not reload by themselves).

BUG REPORTS AND FEATURE REQUESTS
Please post them in our forum with a screenshot and the Serial Monitor text:
  https://www.theengineeringprojects.com/forum/category/lolin-s2-mini-proteus-library

LICENCES AND THIRD-PARTY NOTES
* The board model and the Wi-Fi network (TEPNET.DLL), the symbols and artwork (TEPS2MINI.LIB, TEPLAPTOP.LIB,
  TEPMOBILE.LIB) and the sensor models (TEPFLAME.LIB / .DLL, TEPMQGAS.LIB / .DLL) are made by The Engineering Projects.
  The board's processor is Proteus's own ATmega2560 model. The source code of the models is not included.
* TEP Boards for Proteus (Arduino Code): its core, the variants and the EEPROM, SPI and Wire libraries are modified
  copies of the Arduino AVR core 1.8.6 - GNU Lesser General Public License 2.1 (LGPL 2.1, the text:
  LICENSE-LGPL-2.1.txt); its WiFi, WebServer and the other libraries and our core files are MIT (LICENSE-MIT.txt).
* The demo sketch uses only the core's WiFi and WebServer; the MQ-5 curve numbers are those of MQUnifiedsensor (MIT).
* Proteus is a product of Labcenter Electronics and is not included. LOLIN and WEMOS are names of WEMOS Electronics,
  ESP32-S2 of Espressif Systems. This library is not made or endorsed by them or by Labcenter.

REBUILDING THE FIRMWARE (OPTIONAL)
The HEX file is supplied. Install TEP Boards for Proteus (INSTALLATION step 5), open Arduino Code\S2Mini_Kitchen_Alarm,
select LOLIN S2 Mini (TEP Proteus) and use Sketch > Export Compiled Binary. For a real S2 Mini install "esp32" by
Espressif Systems (3.x), select "LOLIN S2 Mini" and upload - the same sketch (hold 0, tap RST for the first upload).

MODEL SCOPE AND LIMITS
Modelled: the S2 Mini's 27 GPIO pins on a hidden ATmega2560 (Proteus's AVR model, 16 MHz, 3.3 V); digital I/O,
analogRead (1 .. 6, 8, 10, 13, 14) 0 .. 4095, PWM (analogWrite / ledc) and attachInterrupt on any pin through the board
model; RST (a watchdog reset of the hidden processor), 0 (GPIO0), the PWR and blue LEDs; Serial (the board's monitor),
Serial2 on 39 / 37, Wire on 33 / 35 and SPI on 7 / 9 / 11 / 12 (the AVR's hardware); WiFi station mode, DHCP, TCP, UDP,
WebServer, HTTPClient, mDNS and NTP; the other TEP Wi-Fi parts on the same network. Not modelled: the ESP32-S2 itself
(the 240 MHz Xtensa LX7 core, 320 KB of RAM, 2 MB of PSRAM, 4 MB of flash), the native USB (CDC, HID), the touch pads,
the DACs on 17 / 18, the ULP coprocessor. The simulation runs below real time.

VERSION
TEP LOLIN S2 Mini library V1.0 (Oct 2026). Device LOLIN S2 MINI (TEPS2MINI.LIB / TEPNET.DLL), TEP Boards for Proteus
1.25.0 (adds the LOLIN S2 Mini). Demo sketch S2Mini_Kitchen_Alarm V1.0. Demo parts: FLAMEADVTEP and MQ5ADVTEP (the
Advance versions), LAPTOP WIFI MONITOR and MOBILE WIFI MONITOR.