A Greek general, Belias, loses to the commander of the Sōza army, Anantha. According to the terms of
Prompt
A Greek general, Belias, loses to the commander of the Sōza army, Anantha. According to the terms of the war, Anantha asks for the strength of the young men. Among them is also a young girl named Aremis, who is skilled and a fine warrior.
Tags
greek
general,
belias,
loses
commander
sōza
army,
anantha.
according
terms
Model
FLUX.1 Schnell
Size960 × 1440
Created12/17/2025
Generation Time35.8s
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![make the circuit diagram according to this Component Connected To ESP32 PinMultiplexer SIGA0 (Analog pin)MUX S0D0MUX S1D5MUX S2D6MUX S3D8MQ-2MUX Channel 0MQ-135MUX Channel 1LDRMUX Channel 2Sharp Dust Sensor OutputA3 (or D34)Sharp LED ControlD6 (you used it earlier)DHT11D7OLED I2C SDAD21OLED I2C SCLD22Power linesVIN → 5V, GND → GND +-------------------+ +----------------+ +-----------------+
| | | | | |
| MQ135 Sensor |----->| | | |
| (CO₂, VOCs) | | | | |
+-------------------+ | | | |
| | | |
+-------------------+ | | | |
| | | | | |
| MQ2 Sensor |----->| ESP32 |----->| OLED Display |
| (Smoke, LPG) | | (Microcontroller) | (128x64 I2C) |
+-------------------+ | | | |
| | | |
+-------------------+ | | | |
| |----->| | | |
| DHT11 Sensor | | | | |
| (Temp, Humidity) | +----------------+ +-----------------+
+-------------------+ # ESP32 Air Quality Monitor — Circuit Diagram & Detailed Wiring
**Project:** ESP32 Air Quality Monitor (MQ-2, MQ-135, Sharp dust, DHT11, LDR, OLED, 16‑ch MUX)
**Goal:** Clear, school-fair–ready circuit diagram and step‑by‑step wiring instructions so you can build the circuit reliably.
---
## 1) Summary of connections (as you requested)
| Component | Connected to ESP32 pin (D-label) |
| ----------------------------------- | ------------------------------------------------------: |
| Multiplexer SIG | A0 (Analog input) |
| MUX S0 | D0 |
| MUX S1 | D5 |
| MUX S2 | D6 |
| MUX S3 | D8 |
| MQ-2 | MUX channel 0 (SIG via channel 0) |
| MQ-135 | MUX channel 1 |
| LDR | MUX channel 2 |
| Sharp Dust Sensor analog output | A3 (or D34) |
| Sharp LED control (dust sensor LED) | **DO NOT USE D6** — see note below; use **D14** instead |
| DHT11 data | D7 |
| OLED SDA | D21 |
| OLED SCL | D22 |
| Power | VIN → 5V, GND → GND |
> **Important note:** You listed `MUX S2 -> D6` and also `Sharp LED control -> D6` which is a pin conflict. I have moved the Sharp LED control to **D14** in the detailed wiring so the MUX select lines are exclusive. If you want a different pin for the LED, you can change it later but **do not** leave both on the same pin.
---
## 2) Components & extra parts you will need
* ESP32 development board (DevKitC or similar)
* CD74HC4067 or 74HC4067 (16-channel analog multiplexer) **or** 4051 (8-channel) — wiring below assumes a 16‑channel device with S0..S3
* MQ-2 gas sensor module (module with analog output)
* MQ-135 gas sensor module (module with analog output)
* Sharp optical dust sensor (GP2Y1010AU0F or similar)
* DHT11 temperature & humidity sensor
* LDR (photoresistor) + 10k resistor for divider
* 2 × resistors for analog voltage dividers (10k + 20k recommended) for each 5V sensor analog output (see section 5)
* Jumper wires, breadboard, small perf board (optional)
* 0.1 µF decoupling caps (helpful) and a 10 µF capacitor for MQ modules (optional)
* USB cable and 5V supply / power bank (or power from VIN)
---
## 3) High-level Block Diagram (text/ASCII)
```
[MQ-135] --+
[MQ-2 ] --+--> [MUX channel inputs] -- SIG --> A0 (ESP32)
[LDR ] --+
[Sharp Dust Sensor] --> A3 (D34 on ESP32)
Sharp LED control --> D14 (ESP32)
[DHT11] --> D7 (ESP32)
[OLED 128x64 I2C] --> SDA:D21 SCL:D22
[MUX S0..S3] --> D0, D5, D6, D8 (ESP32)
Power: VIN->5V, GND->GND (common ground)
(All analog outputs that can reach 5V must be scaled to 0-3.3V before entering ESP32 ADC pins.)
```
---
## 4) Multiplexer wiring details
Wire the multiplexer as follows (example using CD74HC4067):
* VCC -> 5V (power the sensor side at 5V if modules need 5V)
* GND -> GND (common ground with ESP32)
* SIG (COM) -> **A0** (ESP32 analog pin)
* S0 -> D0 (ESP32)
* S1 -> D5 (ESP32)
* S2 -> D6 (ESP32)
* S3 -> D8 (ESP32)
* INH (enable/inhibit) -> GND (active low; tie low to enable)
**Channel mapping (example):**
* Channel 0 (S3..S0 = 0000) -> MQ-2 analog output
* Channel 1 (0001) -> MQ-135 analog output
* Channel 2 (0010) -> LDR analog divider output
* (Reserve other channels for future sensors)
Use the `selectMuxChannel(int channel)` function in your code to set S0..S3.
---
## 5) Protecting ESP32 ADC from 5V outputs (voltage divider)
Many gas sensor modules and the Sharp dust analog output can produce voltages close to 5V. ESP32 ADC input max is ~3.3V. Use a simple voltage divider for **each** analog sensor line that may reach 5V.
**Suggested divider (maps 0-5V to ≈0-3.33V):**
* Rtop = 10 kΩ
* Rbottom = 20 kΩ
Connection:
```
Sensor analog out ---- Rtop (10k) ----+----> ESP32 ADC pin
|
Rbottom (20k)
|
GND
```
This gives Vout = Vin * (20/(10+20)) = Vin * 0.666 → 5V -> 3.33V safe.
Use this divider on:
* MQ-2 analog out (before the MUX input)
* MQ-135 analog out
* Sharp dust analog out (if it can reach 5V)
> If your sensor modules are already 3.3V modules, you can skip the divider. Always measure with a multimeter first.
---
## 6) Sharp dust sensor special timing (LED pulse)
For Sharp GP2Y1010AU0F:
* Use the LED control pin from ESP32 (we assigned **D14**) to pulse the sensor LED.
* Typical timing (from datasheet):
1. Drive LED LOW (or HIGH depending on wiring) — follow your sensor’s module convention. In your existing code you used `digitalWrite(LED, LOW); delayMicroseconds(280); readAnalog(); delayMicroseconds(40); digitalWrite(LED, HIGH);` — this approach is OK if verified against your module.
2. Read analog value on A3 (D34) after the 280 µs delay.
***Important:*** Verify whether your sensor module expects active LOW or HIGH to turn on the internal IR LED. Test once with the datasheet and a brief code test.
---
## 7) DHT11 wiring
* VCC -> 3.3V or 5V (module supports both; if powering other sensors at 5V, you may use 5V)
* GND -> GND
* Data -> D7 (ESP32)
* If your DHT module has a pull-up resistor installed, you don’t need to add one. If not, add a 5k–10k pull-up between Data and VCC.
---
## 8) OLED wiring (I2C)
* VCC -> 3.3V (recommended for OLED I2C modules) or 5V per module docs
* GND -> GND
* SDA -> D21
* SCL -> D22
If the OLED is 5V-tolerant and you power it from 5V, ensure the SDA/SCL voltage levels are safe; otherwise power it from 3.3V and share ground.
---
## 9) Full wiring table (final)
| From | To | Notes |
| --------------------- | --------------------------------------------------------------------- | ---------------------------------------------------------------------- |
| MQ-2 analog out | MUX input pin for channel 0 (module side) — then SIG → A0 via divider | Use 10k/20k divider on the line feeding MUX if module outputs up to 5V |
| MQ-135 analog out | MUX channel 1 (same divider) | |
| LDR (voltage divider) | MUX channel 2 (read via SIG → A0) | LDR + 10k to form divider; output ~0-3.3V safe |
| MUX SIG (COM) | A0 (ESP32) | ADC input reads selected channel |
| MUX S0 | D0 | |
| MUX S1 | D5 | |
| MUX S2 | D6 | |
| MUX S3 | D8 | |
| Sharp dust analog | A3 (D34) via divider if needed | |
| Sharp LED control | D14 (ESP32) | Pulse according to datasheet timing |
| DHT11 data | D7 | |
| OLED SDA | D21 | |
| OLED SCL | D22 | |
| VCC for sensors & mux | VIN → 5V supply (or separate 5V regulator) | Common GND required |
| ESP32 GND | GND | Common ground for all modules |
---
## 10) Step-by-step breadboard build instructions
1. **Place ESP32** on the breadboard so pins are accessible.
2. **Place the multiplexer** (CD74HC4067) on the breadboard.
3. **Wire power rails**: connect 5V supply to VIN rail, connect ESP32 GND to ground rail.
4. **Connect MUX VCC/GND**: VCC→5V, GND→GND, INH→GND.
5. **Connect MUX SIG to A0** on ESP32 (SIG = COM pin).
6. **Wire MUX select pins**: S0→D0, S1→D5, S2→D6, S3→D8.
7. **Connect MQ-2**: module VCC→5V, GND→GND, Analog out→MUX channel 0 input pin (e.g., pin 0 on MUX). Add voltage divider between module analog out and MUX input if needed.
8. **Connect MQ-135** similarly to MUX channel 1.
9. **Connect LDR**: build an LDR divider (LDR + 10k) and connect its output to MUX channel 2.
10. **Connect Sharp Dust Sensor**: AO → A3 (D34) through divider; LED control → D14.
11. **Connect DHT11**: Data → D7, VCC→3.3V/5V, GND→GND. Add pull-up if needed.
12. **Connect OLED**: SDA→D21, SCL→D22, VCC→3.3V, GND→GND.
13. **Double-check all connections**, ensure no pins are shorted.
14. **Power up** the 5V supply and connect USB to ESP32.
---
## 11) Example MUX select function (code snippet)
```cpp
void selectMuxChannel(int channel) {
digitalWrite(MUX_S0, channel & 1);
digitalWrite(MUX_S1, (channel >> 1) & 1);
digitalWrite(MUX_S2, (channel >> 2) & 1);
digitalWrite(MUX_S3, (channel >> 3) & 1);
delayMicroseconds(5); // let signals settle
}
```
Call `selectMuxChannel(CH_MQ2)` then `analogRead(MUX_SIG_PIN)` to read that sensor.
---
## 12) Calibration & Testing tips
* **MQ sensors**: require a warm-up time (several minutes) and calibration in clean air. Use known concentrations if possible to map raw ADC to ppm.
* **Sharp dust**: map measured voltage to dust concentration using datasheet equation or module guide. Use the pulse-timing carefully.
* **LDR**: test in bright and dark light and record ADC ranges; you can normalize values in code.
* **ADC nonlinearities**: ESP32 ADC is non-linear and noisy. Use averaging (sample many times and average) and optionally apply calibration curves.
---
## 13) Safety & practical notes
* Do **not** feed >3.3V to ESP32 ADC pins. Use voltage dividers or level-shifting.
* Use a **common ground** for all modules and ESP32.
* Keep MQ modules ventilated during testing; they have heating elements.
* Use proper power supply rated for the current (MQ heaters draw current).
---
## 14) Troubleshooting checklist
* If a sensor reads 0 or constant: check wiring, confirm the MUX channel selection, measure the sensor analog out with multimeter.
* If readings are very noisy: sample multiple times and average, add small RC filters (0.1uF + resistor).
* If OLED shows garbage: check I2C address and wiring (SDA/SCL swapped?) and ensure correct voltage.
* If the ESP32 resets: check power supply current and VIN wiring.
---
## 15) What I couldn't draw here
I did a full textual electrical diagram and wiring table. If you want an actual image-style schematic (PNG/PDF) that you can print on chart paper or include in your science fair poster, tell me and I will generate a printable PDF schematic showing all wires laid out on a breadboard (I can produce a downloadable PDF next).
---
If you want the **exact printable schematic** (visual image or PDF), reply: **"Make printable schematic PDF"** and I will produce a downloadable file with the breadboard picture and clear labelled wires.](/_next/image?url=https%3A%2F%2Fluraivin-generated-images.s3.us-east-1.amazonaws.com%2Fimages%2F7939d984-4d7e-4141-9b18-252eefd1034d.jpg&w=3840&q=75)