Project Idea Start

Thought for 18 sec

That is most likely the WEMOS LOLIN32 V1.0.0, which is different from the 38-pin ESP32 DevKit currently shown in the schematic. Before I replace it, please confirm: does your board have 13 pins on each side and a small white LiPo battery connector near the USB socket?

eshan2

no it has 18 on 1 side and 14 at another

Thought for 15 sec

flux

That pin count doesn’t match the standard WEMOS LOLIN32 or ESP32 DevKit footprints, so I shouldn’t guess the socket geometry. Please upload a clear photo of the front and back of the board beside a ruler, or send its exact product link.

eshan2

WhatsApp Image 2026-08-05 at 4.32.47 PM

WhatsApp Image 2026-08-05 at 4.32.48 PM

Thought for 37 sec

flux

That identifies it: it’s a WEMOS D1 R32 V1.0.0, an Arduino Uno-form-factor ESP32 board. I’ll update the carrier design to use its shield-header pinout and mechanical pattern.

Worked for 2 mins 26 sec

flux

The photos confirm your board is a WEMOS D1 R32 V1.0.0, using the Arduino Uno-style shield connector layout—not the current 38-pin ESP32 DevKit footprint.

The existing sensor-carrier schematic remains intact. The following update is still pending because no ACUs are currently available:

Replace the ESP32 DevKit interface with D1 R32 shield headers
Verify and remap the sensor GPIO connections
Apply the Arduino Uno R3 mechanical header pattern
Update the specification, firmware, and bring-up files
Re-run ERC/connectivity checks

No partial replacement was made, so the current schematic has not been left broken.

Map sensor GPIOs

Find D1 R32 footprint

Show header pinout

Check pin conflicts

Update requirements

Files

Schematic

Layout

3D View

Design Notes

Verified module requirements

Table

Load	Rail	Documented current	Interface / logic
MR60BHA2	3.3 V (3.1–3.5 V)	600 mA; source capacity >1 A recommended	3.3 V UART, default 1,382,400 baud
MR60FDA2	3.3 V (3.1–3.5 V)	600 mA; source capacity >1 A recommended	3.3 V UART, default 115,200 baud
INMP441	3.3 V	2.5 mA max normal	3.3 V I2S; L/R low = left; 100 kΩ SD pulldown
MQ-2 module	5 V	800 mW ≈ 160 mA	AO may approach 5 V; DO omitted because it may be 5 V logic
DHT11	3.3 V	2.5 mA measuring	single-wire DATA, 5 kΩ recommended pull-up
ESP32 DevKitC	isolated 5 V input	500 mA conservative Wi-Fi/transient allocation	3.3 V GPIO
Optional XIAO	protected 5 V	250 mA provisional connector allocation	3.3 V UART logic expected; verify exact future board

Worst-case power budget

Two radar modules: 1.20 A at 3.3 V = 3.96 W. At 90% buck efficiency from 5 V: 0.88 A input.
ESP32 development board allocation: 0.50 A at 5 V.
MQ-2 module: 0.16 A at 5 V.
Optional XIAO header: 0.25 A at 5 V.
Indicator and small auxiliaries: 0.02 A.
Total protected-5 V worst-case allocation: 1.81 A.
F1 is a 3 A hold PTC, providing 1.66× margin over the calculated allocation. A USB-C source explicitly advertising 5 V / 3 A is required; CC pulldowns alone do not negotiate or guarantee 3 A.

Power architecture

USB-C VBUS → F1 3 A PTC → 5V_PROTECTED.
SMF5.0A clamps the protected rail; 470 µF bulk plus 100 nF bypass support load steps.
SS34 series diode feeds only the ESP32 DevKit 5V pin. Its orientation allows carrier-to-board current and blocks reverse current from the DevKit USB rail back into the carrier/laptop source.
TPS62823 creates 3V3_RADAR. It is rated 3 A and switches at about 2.2 MHz, satisfying the radar documentation's ≥2 MHz DCDC recommendation.
TPS62823 values: 470 nH inductor, 4.7 µF input, 2×10 µF output, 450 kΩ/100 kΩ feedback (0.6×(1+450/100)=3.30 V), 120 pF feed-forward.
Dev-board 3V3 powers only INMP441 and DHT11 (<6 mA combined), because the DevKit regulator rating is not documented and is not used for the radar loads.

GPIO map

Table

ESP32 pin	Net	Function
GPIO17 TX / GPIO16 RX	RADAR_BHA_RX / RADAR_BHA_TX	UART1 to MR60BHA2 (module RX / TX)
GPIO23 TX / GPIO22 RX	RADAR_FDA_RX / RADAR_FDA_TX	UART2 to MR60FDA2 (module RX / TX)
GPIO14	I2S_BCLK	INMP441 SCK
GPIO25	I2S_WS	INMP441 WS
GPIO32	I2S_SD	INMP441 data input
GPIO34 (ADC1_CH6)	MQ2_ADC1_CH6	MQ-2 AO through 10 kΩ / 20 kΩ divider
GPIO27	DHT11_DATA	DHT11 single-wire data
GPIO13 TX / GPIO33 RX	XIAO_SWUART_TX/RX	optional software UART

UART0 GPIO1/GPIO3 remains reserved for programming/debug. GPIO6–11 are unused. MQ-2 uses ADC1, so Wi-Fi does not disable the reading. Boot-strapping pins GPIO0/2/5/12/15 are avoided.

Connector pin labels

J2/J3: 1=3V3_RADAR, 2=GND, 3=module TX → ESP RX, 4=ESP TX → module RX.
J4: 1=3V3_AUX, 2=GND, 3=SCK, 4=WS, 5=SD, 6=L/R=GND (left channel).
J5: 1=5V_PROTECTED, 2=GND, 3=AO, 4=DO intentionally not connected.
J6: 1=3V3_AUX, 2=DATA, 3=GND.
J7: 1=5V_PROTECTED, 2=GND, 3=ESP RX, 4=ESP TX.

Analog protection calculation

R6=10 kΩ upper and R7=20 kΩ lower: VADC=VAO×20/(10+20)=0.6667×VAO. A 5.0 V AO becomes 3.33 V. C7=100 nF gives approximately 159 Hz pole against the 10 kΩ Thevenin scale and filters heater/comparator noise. Firmware must use 11 dB attenuation and calibrate the ADC; this is not a precision gas-concentration instrument without sensor calibration.

Remaining assumptions

Radar connector mechanics vary by module/adapter; J2/J3 are labeled logical headers, not asserted as a mating footprint for the bare 29-pad radar module.
DevKitC-32UE is the selected 38-pin original-ESP32 carrier target. Confirm the user's exact development-board header spacing before PCB layout.

Verified module requirements
Worst-case power budget
Power architecture
GPIO map
Connector pin labels
Analog protection calculation
Remaining assumptions