ESP32-WROOM-32D and ESP32-WROOM-32U Development Board
The ESP32-WROOM-32D and ESP32-WROOM-32U are Espressif’s dual-core WiFi and Bluetooth development boards — same internals, different antenna. The 32D has a PCB trace antenna built in. The 32U replaces it with a u.FL connector for an external antenna, reaching up to 1.5 km line-of-sight range with a 3 dBi antenna. Both run the Xtensa LX6 dual-core processor at 240 MHz with 520 KB SRAM. At £4.90, these are the boards you prototype on before committing to a custom PCB.
- Dual-core Xtensa LX6 at 240 MHz — runs WiFi stack and your application code on separate cores
- 4 MB SPI flash / 520 KB SRAM — enough headroom for MQTT, OTA, and sensor logging simultaneously
- WiFi 802.11 b/g/n + Bluetooth 4.2 BR/EDR and BLE — no extra modules needed
- Hardware AES encryption — secures data on-device without slowing the processor
- OTA firmware updates — push new code over WiFi after deployment, no USB required
- -40°C to +105°C operating range — works in outdoor enclosures and near heat sources
| Specification | ESP32-WROOM-32D | ESP32-WROOM-32U |
|---|---|---|
| Antenna | PCB trace (integrated) | u.FL / IPEX connector (external) |
| Module dimensions | 18 × 31.4 × 3.3 mm | 18 × 19.2 × 3.2 mm |
| Max WiFi range | ~100 m open air | Up to 1.5 km with 3 dBi antenna |
| Flash | 4 MB SPI (32 Mbit) | |
| Processor | ESP32-D0WD, Xtensa LX6 dual-core, 80–240 MHz | |
| SRAM | 520 KB | |
| ROM | 448 KB | |
| WiFi | 802.11 b/g/n, 2.4 GHz | |
| Bluetooth | v4.2 BR/EDR + BLE | |
| GPIO pins | 38 (including ADC, DAC, UART, SPI, I2C, I2S, PWM) | |
| Supply voltage | 3.0 V – 3.6 V | |
| Operating temperature | -40°C to +105°C | |
What is the difference between ESP32-WROOM-32D and ESP32-WROOM-32U?
The only hardware difference is the antenna. The ESP32-WROOM-32D has a PCB trace antenna etched directly onto the module — compact, no extras needed. The ESP32-WROOM-32U removes the PCB antenna and adds a u.FL (IPEX) connector for an external antenna. This makes the 32U module 12 mm shorter but requires you to attach a separate 2.4 GHz antenna.
Everything else — processor, flash, RAM, WiFi, Bluetooth — is identical between the two variants.
Does the ESP32-WROOM-32U need an external antenna fitted?
Yes, and this matters: running the ESP32-WROOM-32U without an antenna connected can damage the RF power amplifier. You must fit a compatible 2.4 GHz antenna to the u.FL connector before powering the board. A standard IPEX to SMA pigtail with a 2.4 GHz stub antenna works. The module does not include an antenna — order one alongside this board.
What is the WiFi range of the ESP32-WROOM-32U?
With a 3 dBi external antenna, the ESP32-WROOM-32U reaches up to 1.5 km line-of-sight range. In a typical indoor environment with walls and interference, expect 50–200 m depending on antenna placement. The ESP32-WROOM-32D’s PCB antenna suits indoor use within ~100 m of a router.
Use the 32U when the board is inside a metal enclosure, a 3D-printed case, or any location where the PCB antenna would be obstructed or where extended outdoor range is needed.
Is the ESP32-WROOM-32D dual-core?
Yes. Both the 32D and 32U use Espressif’s ESP32-D0WD chip with two Xtensa LX6 cores running at up to 240 MHz. One core typically handles the WiFi and Bluetooth stack while the other runs your application code, keeping connectivity tasks from blocking your firmware logic.
Does the ESP32-WROOM work with the Arduino IDE?
Yes. Install Espressif’s ESP32 board support package via Arduino IDE’s Boards Manager, select “ESP32 Dev Module”, and upload over USB using the standard workflow. Both variants are also compatible with MicroPython, ESP-IDF, and PlatformIO.
Best for
Best for: WiFi sensor nodes, BLE beacon projects, home automation controllers, MQTT-based IoT dashboards, ESP-NOW wireless mesh networks, battery-powered weather stations, smart plug prototypes, wearable electronics, university lab assignments, Arduino IDE learning projects, industrial telemetry inside enclosures (32U), and any build needing simultaneous WiFi and Bluetooth.
What’s In The Box
- 1× ESP32-WROOM-32D or ESP32-WROOM-32U development board (select variant above)
- Note: the ESP32-WROOM-32U does not include an external antenna — one must be fitted before use
Why Kunkune
Shipped from the UK via Royal Mail — typically 1–2 days. Same-day dispatch on orders placed before 2pm. 60-day returns. No drama.
Buying in bulk? For orders of 10+ units or trade pricing, contact us for a custom quote.
