6/16/23 New and improved schematics and layout diagrams now available!

Similar to my other "project boards", this board combines outlines for an ESP32 and power supply circuitry with plenty of prototyping space for SMD and through-hole parts. This enables rapid prototyping of projects involving the ESP32, as well as being well suited for unique or nearly unique parts for home hobby projects. By integrating common SMD footprints on the prototyping board itself, the need to use breakout boards is reduced, and by using real soldered connections (as opposed to solderless breadboard), reliability is greatly improved, and the project can be moved around without worrying about wires getting pulled out. These boards make it easier than ever to make a durable prototype or one-off project with the ESP32.

The ESP32 is a WiFi enabled microcontroller from Espressif, a follow-on to the wildly successful ESP8266, with many of the limitations of the ESP8266 directly addressed. The processor is faster, it's dual-core allowing one core to handle wifi functions and the other to run the rest of the application code (eliminating the watchdog-reset issue), plus more pins, better peripherals, and Bluetooth LE capability. They can be programmed in C using the Espressif SDK, in easy-mode C using the Arduino IDE (free third-party core required), or in Javascript using Espruino.

This board features pads for an ESP32 in the ESP-WROOM32 modules on a 2" x 4" board (same outline and hole location as my general purpose 2"x4" boards ). It is compatible with both WROOM32D and WROOM32U modules. All the GPIO pins except those used for the SPI flash are broken out into groups of through holes along the bottom edge. The power supply section can use an SOT-223 regulator with one of two pinouts (only one regulator at a time), either the 1117-series ones, with VOut on the tab (using the outline on the top of the board), or the other pinout common for many lower-dropout regulators, with ground in the middle (using the outline on the bottom of the board). Input and output caps on the regulator should be 1206 and meeting the specs for the regulator. The ground and Vcc lines are routed around the board with nice, thick traces, so you're never far from power and ground, and Vin is accessible in two points as well, including right in the middle of the SMD prototyping area to supply any level shifting IC's you may need.

Suggested Components (not included):

• ESP32 in WROOM OR WROVER package, coming soon (just be sure to select the right version).
• Warning: See below notes on identifying parts.
• Two 3x6mm buttons for flash and reset (The really cheap ones, available from eBay/Aliexpress)
• 1117-series 3.3v LDO regulator (like ZLDO1117 )
• Input and output capacitors for LDO regulator (see datasheet for your regulator) in 1206 package
• Barrel Jack, 5.5mm/2.1mm (center positive)
• Extra decoupling capacitor (I use 4.7uF) for C
• ~10k 1206 pull-up resistor for CH_PD
• 0.1" pin header (for making connections to other devices)

Identifying ESP32 modules

The name at the top (ESP32-WROVER-__ or ESP32-WROOM-32__) identifies the die rev of the chip WROOM modules have been marked 32B-32E; 32E and 32UE are the latest at time of writing, 32E uses PCB antenna, while 32UE has a has a uFL connector to connect an external antenna. WROVERs had a WROVER32-B, II, III, and E and IE. E again is the latest one with the fewest silicon bugs (and IE the version with the antenna connector instead of PCB ttrace entenna), so that's the one you want). Take care to actually order the new version - many sellers are trying to unload the old ones that they had in stock.

They are additionally manufactured with three sizes of flash chip installed - 4MB, 8MB, and 16MB and - on the WROVER - several sizes of PSRAM (8 is definitely an option, not sure about others.

This is marked at the bottom of the module in the form XXH__ where __ is 32, 64, or 28 (128, with the 1 truncated to fit, that is, it's the size of the flash in megabits for WROOM-32E's. WROVERS have analogous markings formatted differently: XXN__R_ - the first __ is the flash size, this time in megabytes, and the second number is PSRAM size (2 or 8 in MBytes). So the best one is the WROVER-E with code XXN16R8 at the bottom.

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