ESP32 Sensor Project

ผมจะปรับ schematic ให้เป็นเวอร์ชัน “ต่อง่ายบน breadboard”: ลดความสับสนของสาย, ใส่คำอธิบาย pin order/บทบาทแต่ละ connector, จัดกลุ่มให้ตามการต่อจริง และตรวจ ERC อีกรอบครับ
ตอนนี้ผมเริ่มงานปรับให้ “ต่อง่าย” แล้ว แต่ระบบแจ้งว่า ACUs ไม่พอ จึงยังแก้ schematic ต่อไม่ได้ในรอบนี้
ทำไปแล้วก่อนหน้านี้:
  • สร้าง schematic หลักครบ: ESP32 2 บอร์ด, HX711 + Load Cell, MPU6050, DS18B20, Battery Shield connector
  • ต่อ power, GND, I2C, HX711, DS18B20 และ UART optional ระหว่าง ESP32
  • ตรวจ ERC schematic แล้วผ่าน
  • สร้างไฟล์ Firmware Starter, Project Specification, Bring-Up Plan และ Regulatory Notes
งานที่เหลือสำหรับเวอร์ชัน “ต่อง่ายที่สุด”:
  • จัด schematic ใหม่ให้เหมือนลำดับการเสียบสายบน breadboard
  • ใส่คำอธิบาย pin ของ J1/J2 ให้ชัด เช่น 5V, 3V3, GND, E+, E-, A+, A-
  • ลดความสับสนของ ESP32 2 บอร์ด และทำให้ U1 เป็นบอร์ดหลักชัดเจน
  • อัปเดตไฟล์คำแนะนำการต่อสายให้เป็นขั้นตอนสำหรับมือใหม่
  • ตรวจ ERC/DRC หลังปรับอีกครั้ง
จัด schematic ง่าย
อธิบาย pin
คู่มือต่อสาย
ตรวจ ERC/DRC
U4
U5
C3
Capacitance
100nF
J1
C2
Capacitance
100nF
U2
C1
Capacitance
470uF
J2
U1
R1
Resistance
4.7kohms
R2
Resistance
4.7kohms
R4
Resistance
220 ohms
R5
Resistance
220 ohms
U3
R3
Resistance
4.7kohms

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Project Specification — ESP32 Road Soil Sensor
Project Overview
Status: Draft schematic complete for prototype review.
Battery-powered ESP32 prototype for measuring road-surface / soil-layer condition using a 5 kg load cell with HX711, MPU6050 motion sensing, and DS18B20 temperature sensing.
Intended Use
  • Breadboard/prototype build using ESP32 38-pin development boards, jumper wires, and 18650 battery shield.
  • Intended for learning and early data collection, not production or outdoor-rated deployment yet.
What the Device Should Do
  • Read force/weight from a 5 kg load cell through HX711.
  • Read tilt/vibration from MPU6050 over I2C.
  • Read surface temperature from a waterproof DS18B20 probe.
  • Optionally forward sensor data from ESP32 board U1 to ESP32 board U2 over UART.
Main Features
  • Two ESP32 development boards: U1 primary sensor node, U2 optional receiver/controller.
  • 5V and 3.3V rails from an external 18650 Battery Shield V3 output header.
  • 3.3V logic on ESP32 GPIO and sensor buses.
  • I2C pull-ups and DS18B20 1-Wire pull-up included.
  • Bulk capacitor on 5V rail for ESP32 Wi-Fi current peaks.
System Architecture

Diagram


DOUT GPIO32, SCK GPIO33 I2C SDA GPIO21, SCL GPIO22 1-Wire GPIO4 UART via GPIO25/26 + node_220R 18650 Battery Shield V3 output J1 5V rail 3V3 rail ESP32 U1 ESP32 U2 HX711 analog/excitation VCC HX711 VDD logic MPU6050 DS18B20 5 kg Load Cell J2
Hardware Subsystems
  • Power: J1 represents Battery Shield V3 outputs. J1 PIN_1 = 5V, PIN_2 = 3V3, PIN_3/PIN_4 = GND. Verify real shield pin order before wiring hardware.
  • MCU: U1 and U2 are ESP32-DEVKITC-VE functional stand-ins for the user’s 38-pin ESP32 DevKit boards.
  • Load Cell: U3 HX711 module connects to load cell connector J2.
  • Motion: U4 MPU6050 module on I2C bus with 4.7 kΩ pull-ups.
  • Temperature: U5 DS18B20 powered at 3.3V with 4.7 kΩ pull-up on DQ.
Interfaces and Connections

Table


InterfaceNet / PinsNotes
Battery shield outputJ1 PIN_1 5V, PIN_2 3V3, PIN_3/PIN_4 GNDConfirm physical module pinout before wiring.
HX711 dataU1 IO32 = HX711_DOUT, U1 IO33 = HX711_SCK3.3V logic via HX711 VDD.
Load cellJ2 PIN_1 E+, PIN_2 E-, PIN_3 A+, PIN_4 A-Typical colors: red, black, green/blue, white; verify actual cell.
MPU6050 I2CU1 IO21 SDA, U1 IO22 SCL4.7 kΩ pull-ups to 3V3.
DS18B20U1 IO4 = DS18B20_DQ4.7 kΩ pull-up to 3V3.
ESP32-to-ESP32 UARTU1 IO25 -> R4 -> U2 IO26, U2 IO25 -> R5 -> U1 IO26Optional UART link.
Power and Runtime Expectations
  • Use one power source at a time for the ESP32 boards: battery shield 5V/VIN or USB, not both unintentionally.
  • Battery shield must support ESP32 Wi-Fi peak current for two boards; target at least 700 mA to 1 A available on 5V.
  • C1 = 470 µF bulk capacitor on 5V rail for Wi-Fi current bursts.
Power Tree and Power Budget

Table


RailSourceLoadsDesign expectation
5VBattery Shield V3 J1 PIN_1U1 5V, U2 5V, HX711 VCC, C1Up to ~1 A recommended for two ESP32 boards.
3V3Battery Shield V3 J1 PIN_2 / ESP32 regulator rail depending buildU1/U2 3V3 pins, HX711 VDD, MPU6050, DS18B20, pull-upsLogic rail; never pull sensor signals to 5V.
GNDJ1 PIN_3/PIN_4All modulesCommon ground required.
Firmware-Relevant Hardware Requirements
  • U1 firmware reads all sensors and can transmit CSV/JSON over UART to U2.
  • U2 firmware can act as a serial receiver/logger.
  • Firmware must configure I2C on GPIO21/22 and DS18B20 on GPIO4.
Important Design Decisions
  • HX711 VCC is tied to 5V for load-cell excitation; HX711 VDD is tied to 3.3V to keep ESP32 logic safe.
  • U1:VP and U2:VP are tied to GND only to clear a library ERC issue where VP is tagged as a power input; electrically this leaves the unused ADC input at a defined low level.
  • Battery Shield V3 is represented as a connector because the exact module was not available in the Flux library.
Assumptions
  • The Battery Shield V3 provides usable 5V, 3V3, and GND outputs.
  • The MPU6050 module can operate from 3.3V and has no conflicting onboard pull-ups to 5V.
  • The DS18B20 waterproof cable color order will be verified before hardware wiring.
Change Notes
  • Initial schematic created with U1/U2, HX711, load cell connector, MPU6050, DS18B20, power connector, pull-ups, UART series resistors, and decoupling/bulk capacitors.
  • Project Overview

  • Intended Use

  • What the Device Should Do

  • Main Features

  • System Architecture

  • Hardware Subsystems

  • Interfaces and Connections

  • Power and Runtime Expectations

  • Power Tree and Power Budget

  • Firmware-Relevant Hardware Requirements

  • Important Design Decisions

  • Assumptions

  • Change Notes

ESP32 Road Soil Sensor

ESP32 Road Soil Sensor thumbnail
Battery-powered ESP32 prototype for measuring soil/road-surface condition using HX711 load cell, MPU6050 vibration/tilt sensing, and DS18B20 temperature sensing from 18650 battery power.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$14.71–$16.43

Digi-Key

$22.00

HQonline

$0.85–$1.23

LCSC

$26.31

Mouser

$21.02

Verical

$16.63–$17.68

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