ESP-WROOM-32 is likely the most popular ESP32 WiFi + Bluetooth module on the market, but a few months ago, Espressif Systems unveiled two variants named ESP32-WROOM-32D / ESP32-WROOM-32U, which are based on ESP32-D0WD (5x5mm package) instead of ESP32-D0WDQ6 (6x6mm package), and are said to offer better RF performance
ESP32-WROOM-32D is the most similar to ESP-WROOM-32 since it also comes with a PCB antenna, while ESP32-WROOM-32U is much smaller as it relies on an external WiFi/Bluetooth antenna via a u.FL connector. Both new modules are pin-to-pin compatible with ESP-WROOM-32
- CPU – Espressif ESP32-D0WD dual core Tensilica processor
- Storage – 32Mbit SPI flash
- Crystal – 40 MHz
- Connectivity – Wi-Fi 802.11 b/g/n up to 150 Mbps, Bluetooth 4.2 LE
- I/Os – 38- catellagated pin with I/Os + GND plane
- ESP32-WROOM-32D – on-board antenna
- ESP32-WROOM-32U – u.FL connector for external IPEX antenna
- ESP32-WROOM-32D – 18 x 25.5 x 3.1 mm
- ESP32-WROOM-32U – 18 x 19.2 x 3.2 mm
There looks to be some confusion about the product names, as Espressif Systems names the modules ESP32-WROOM-32D and ESP32-WROOM-32U on the official product page (with datasheet, TRM, etc…), but whoever made the module pictured above, named the former ESP-WROOM-32D.
The modules were first spotted on by Reddit users three months ago, but I’ve just found out about it through Electrodragon which sells the original ESP-WROOM-32 and ESP-WROOM-32D modules for 3.06 Euros, and the ESP32-WROOM-32U module for 3.14 Euros. The D model will however only start shipping around the end of March.