Adafruit Metro ESP32-P4 Hydra, product 6536, $34.95. Two things make it worth a look if you build physical pieces with screens in them, and one of them is a warning printed in the product’s own title.
Two chips, specific jobs
The ESP32-P4 is the main processor: a dual-core 32-bit RISC-V at up to 360 MHz, plus a separate 40 MHz low-power RISC-V core, with AI instruction extensions, hardware H.264 and JPEG codecs and hardware cryptography. The chip carries 768 KB of high-performance SRAM and 32 KB of low-power SRAM.
The P4 has no radio. So an ESP32-C6 sits alongside it as a wireless coprocessor, connected over SDIO, providing WiFi. Adafruit notes the C6’s radio also supports Bluetooth LE 5.3, Thread and Zigbee, but that exposing those “may require additional firmware” — and that the C6 can be reprogrammed through GPIO from the P4.
On board: 16 MB QSPI NOR flash and 16 MB PSRAM. Worth noting that the P4’s own specification lists 32 MB of internal PSRAM while this board provides 16 MB; the product page does not explain the difference, and we are not going to guess at it.
The connectors are the actual feature
This is the part that changes what you can build on a Thursday afternoon.
Display: two-lane MIPI DSI on a 22-pin, 0.5 mm-pitch connector using the Raspberry Pi layout. Adafruit names the 5” and 7” Raspberry Pi Touch Display 2 (720×1280, capacitive touch) as compatible.
Camera: two-lane MIPI CSI on a second 22-pin connector. Compatible cameras listed are Zero Spy Cameras with OV5647 sensors in 70°, 120° and 160° lenses — and, explicitly, IMX708 “v3” cameras are not supported.
A microcontroller that drives a 720×1280 capacitive touchscreen over DSI, at this price, in an Arduino footprint, is a different proposition from the SPI displays that ESP32 projects have lived on. SPI gets you a small panel and a visible refresh. A two-lane DSI link gets you a phone-sized screen running properly.
And adopting the Raspberry Pi connector layout rather than inventing one means the display and camera ecosystem already exists. If you have a Pi 5 and a Touch Display 2 on the bench, you can move the panel.
The rest of the board
- Metro/Arduino Uno headers: D0–D13, six analog inputs, I2C/I3C, plus a separate six-pin SPI header. All GPIO is 3.3 V logic — worth remembering if you are bringing 5 V Uno shields.
- STEMMA QT connector for I2C/I3C devices.
- microSD socket on 4-bit SDIO.
- A dedicated hardware/ROM UART for debugging.
- RGB NeoPixel, a separate D13 user LED, Reset and Boot buttons.
- USB-C for power, programming, serial debugging and TinyUF2 drag-and-drop firmware updates.
- USB-A high-speed host port with software-controlled power and a dedicated 5 V boost supply, so it can host devices on battery.
- Power from a 7–12 V barrel jack, USB-C, or a single-cell LiPo connector, with battery-voltage monitoring, onboard charging, charge and status indicators, and a power switch.
- 72.3 × 53.3 × 14.7 mm.
The USB-A host port with its own boost converter and on/off control is the quietly useful one. A microcontroller that can power and talk to a USB device while running from a battery opens up MIDI controllers, keyboards, webcams and storage without a powered hub in the enclosure.
The warning in the title
The product is listed as “with 16 MB PSRAM - v1 Chipset”, and the page says, in capitals:
PLEASE NOTE: This is NOT the ESP32-P4X chip, we are currently shipping with “v1” chips.
That is the silicon revision, stated up front rather than in an FAQ. If your project needs the newer P4X, this is not the board, and Adafruit has told you so on the buy page instead of letting you discover it after flashing.
We note it approvingly and also as a caution: a board whose title has to carry a chip-revision disclaimer is a board on a moving platform. Which leads to the other thing to check before ordering.
The product page does not state Arduino, CircuitPython or ESP-IDF support. It mentions TinyUF2 drag-and-drop updates, and the need for interfacing firmware to get some of the C6’s radio features out. For a board announced this week on a relatively new SoC, assume the software story is in progress and check the current state of ESP-IDF and Arduino-ESP32 support for the P4 — and the DSI driver situation specifically — before you commit a project to it. The hardware being ready and the display stack being ready are different milestones.
At the time we looked, Adafruit listed 37 in stock, limit two per customer, which is its own signal about where this is in its life.
Who it is for
If you want a self-contained piece with a real screen — a gallery label that plays video, an instrument with a proper UI, a kiosk, a camera that does on-device JPEG or H.264 — this is a cheaper and smaller route than a single-board computer, with the hard-realtime behaviour a microcontroller gives you and none of an operating system’s boot time or SD-card corruption.
If you need Linux, a browser, or Python with the scientific stack, it remains the wrong tool and a Pi is the right one.
Sources
- Adafruit Metro ESP32-P4 Hydra - with 16 MB PSRAM - v1 Chipset
- Adafruit Metro ESP32-P4 Hydra – An Arduino UNO-shaped ESP32-P4 + ESP32-C6 board with WiFi 6, MIPI interfaces — CNX Software
- ESP32-P4 product page — Espressif
- Raspberry Pi Touch Display 2