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Green PCB with four blue relay modules and USB-C port

NuoTo

NuoTo ESP32 4-Channel Relay Board 4MB Flash 8MB PSRAM

SKU CH-Y9DG-CETJM

ESP32 development board with four opto-isolated relays, 4 MB flash, 8 MB PSRAM, 16 GPIOs and 12–24 V DC input

  • CPU TypeOther
  • ESP32-Wrover-B MCU delivers Wi-Fi and BLE connectivity
  • 4MB Flash plus 8MB PSRAM handles larger firmware and data buffers
  • Four opto-isolated relays on GPIOs 21, 19, 18, 5 switch loads safely
  • 16 expansion GPIOs and multiple bus interfaces add sensors or displays
  • DC 12–24 V input with 360–450 mW draw suits industrial power rails

Development board with four isolated relays

The NuoTo ESP32 board integrates an ESP32-Wrover-B module with 4 MB flash and 8 MB PSRAM, providing Wi-Fi 802.11 b/g/n and Bluetooth BLE 4.2 connectivity. Four optocoupler-isolated relays are controlled via GPIO 5, 18, 19 and 21, each with a blue status LED. Sixteen additional GPIO pins are broken out for expansion, and the board accepts a DC 12 to 24 V supply while drawing 360 to 450 mW. It is aimed at makers and engineers building remote-switch or automation projects that need wireless control.

Sustained operation within relay and power limits

Each relay channel is electrically isolated, allowing the board to switch external loads continuously without coupling transients back to the MCU. The on-board regulator handles the full 12 to 24 V input range during extended runs, and the 360 to 450 mW draw remains stable while all four relays are energised. Firmware must manage watchdog resets and thermal budget, as the ESP32-Wrover-B has no active cooling and the relays generate heat under constant switching.

Programming requires the T-U2T downloader

Code upload is only possible through the proprietary T-U2T automatic downloader, which connects via USB Type-C; without that hardware the board cannot be reprogrammed. The ESP32 exposes UART, SPI, I2C, CAN, I2S and SDIO buses, but none of these interfaces serve as a programming path. Buyers who do not already own a compatible T-U2T unit must obtain one separately, and projects that demand standard USB serial flashing are not supported.

Highlights

  • ESP32-Wrover-B MCU delivers Wi-Fi and BLE connectivity
  • 4MB Flash plus 8MB PSRAM handles larger firmware and data buffers
  • Four opto-isolated relays on GPIOs 21, 19, 18, 5 switch loads safely
  • 16 expansion GPIOs and multiple bus interfaces add sensors or displays
  • DC 12–24 V input with 360–450 mW draw suits industrial power rails

Specifications

CPU TypeOther

Questions about this item

How much power does the ESP32 board draw when all four relays are energised continuously?

Power consumption is rated between 360 and 450 mW while the relays are active.

What additional hardware is required to upload firmware to this relay board?

A T-U2T automatic downloader and a USB Type-C data cable are needed to program the ESP32.

Can the 16 expansion GPIOs be used while the four onboard relays are connected to GPIO 5, 18, 19 and 21?

Those four GPIOs drive the relays, leaving the remaining expansion pins free for other peripherals.

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