ESP32 Power Monitor

Created 3 project docs

Block Diagram

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Block Diagram Functional Groups
  1. CONTROL Power
  2. MCU / I2C / Sensor
  3. Protected Test Input / Current Sense
  4. Relay Drivers
  5. HOT Load Bank
  6. Mechanical

Project Specification

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Project Specification Project Overview
  • Status: Review
  • Beginner-friendly ESP32-C3 instrument for monitoring and applying a four-step resistive load to a nominal 12 V, up-to-2 A PSU.
Intended Use
Bench validation of low-voltage DC supplies. Prototype/educational assembly; exposed load resistors become hot.
What the Device Should Do
  • Measure protected PSU voltage and high-side current.
  • Switch four equal load branches independently.
  • Read a remotely mounted DS18B20 temperature probe without phantom powering when disabled.
  • Keep 5 V relay-module inputs electrically isolated from ESP32 GPIO by NPN open-collector stages.
Main Features
  • ESP32-C3 module/header implementation.
  • ADS1115 voltage channel and INA226 current monitor, both at 3.3 V logic.

Design Review Notes

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Design Review Notes Corrections Implemented / Required
  • ADS1115 and INA226 logic at 3.3 V; exactly one external I2C pull-up pair to 3.3 V.
  • I2C moved to GPIO6/7; GPIO2/8/9 left uncommitted.
  • Four NPN open-collector relay interfaces prevent direct 5 V module pull-up exposure to ESP GPIO.
  • DS18B20 VDD and OneWire pull-up both switched; GPIO4 must be LOW or high-Z while power is off.
  • Test input changed to >=5 A screw terminal with T2A fuse and >=3 A/40 V Schottky.
  • ADC divider changed to 100 kΩ / 22 kΩ / 100 nF on protected rail.
  • Load bank corrected to 0.5 Ω common safety resistance plus four 24 Ω branches; LED resistors 1.5 kΩ.
  • Added rail bulk/decoupling and >=1 A continuous control-power requirement.
Module Selection / Assembly Constraints

flux

I completed the design audit and identified required corrections, but schematic creation could not start because no ACUs are currently available.
Key corrections ready to implement include 3.3 V-safe I²C/ADC power, non-strapping GPIO6/7 for I²C, protected relay drivers, phantom-power-safe DS18B20 switching, a ≥5 A screw-terminal test input, and improved fuse/diode/thermal provisions. Once ACUs are available, the schematic, ERC verification, and detailed project files remain to be completed.
List priority corrections
Document design constraints
Audit voltage and GPIO
Review safety BOM

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Schematic

Layout

3D View

Schematic of ESP32-C3 PSU Load Tester
U1

ESP32-C3 PSU Load Tester

ESP32-C3 PSU Load Tester thumbnail