Leaf board pinout

Leaf board — pinout & IO reference

Hardware v1.0. This is the board inside every MeshCam leaf camera, and the board sold as the bare-board SKU.

It is an ESP32-S3 module-direct design: no carrier, no dev board underneath. The GPIO map below is the whole pin budget. Read it before planning custom firmware, because there are fewer spare pins than a raw ESP32-S3 dev board suggests.

Overview

MCU — ESP32-S3-WROOM-1-N16R8: 16 MB flash, 8 MB octal PSRAM, native USB.
Camera — 24-pin 0.5 mm FFC, same pinout as the ESP32-S3-EYE and Freenove camera boards. Any standard DVP camera module on that connector family works (OV2640, OV3660, OV5640).
Radio — RAK3172 (STM32WL + sub-GHz radio) on US915, running RAK's stock RUI3 firmware as a UART modem. The ESP32 talks to it over UART and treats it as a LoRa modem; it does not bit-bang the radio directly.
Sensors — PIR (AM312, plug-in) for wake-on-motion, BME280 (plug-in socket) for temperature, humidity and pressure.
Power — solar or USB input charges an on-board 26650 LiFePO4 cell. No external battery connector: the cell drops into an on-board holder.
Storage — microSD, SDMMC 1-bit mode (not SPI).
Board size — 86 × 95 mm, four M4 mounting holes.

Connector numbering skips J4, J5 and J7. Those existed on earlier prototype revisions (a socketed radio bay, an external battery harness) and were removed before production. Nothing is missing on your board.

Connector map

Ref	Connector	Location	Function
J1	USB-C receptacle	left edge	Charge input (5 V) plus native USB serial console and firmware flashing. Does not power the board — see the power tree below.
J2	24-pin 0.5 mm FFC	top edge	Camera module (DVP interface).
J3	JST-PH, 3-pin	top edge	PIR sensor input (AM312).
J6	JST-XH, 2-pin	top edge	Solar panel input, nominal 6 V.
J8	microSD (push-push)	left edge	Storage, SDMMC 1-bit mode.
J9	u.FL	radio corner	LoRa antenna, 915 MHz (US915).
J10	2.54 mm socket, 4-pin	left side	BME280 environmental sensor (I2C).
J11	JST-PH, 3-pin	top edge	IR illuminator output, PIR-gated. Feeds an external 12 V boost and 850 nm array for night captures.

J6, J3 and J11 sit next to each other along the top edge, in that order. Their housings use two different JST families, XH on J6 and PH on J3/J11, specifically so the solar plug cannot be mis-seated into the PIR or IR sockets.

J2 — camera FFC (24-pin, 0.5 mm pitch)

Bottom-contact ribbon: contacts face down, toward the board.

Pin	Signal	Pin	Signal	Pin	Signal	Pin	Signal
1	NC	7	VSYNC	13	XCLK	19	Y2
2	AGND	8	PWDN	14	Y8	20	Y5
3	SDA	9	HREF	15	DGND	21	Y3
4	AVDD (2.8 V)	10	DVDD (1.5 V)	16	Y7	22	Y4
5	SCL	11	DOVDD (2.8 V)	17	PCLK	23	NC
6	RESET	12	Y9	18	Y6	24	NC

J3 — PIR input (JST-PH, 3-pin)

Pin	Signal
1	3V3
2	PIR_OUT — digital, wakes the board from deep sleep
3	GND

J11 — IR illuminator output (JST-PH, 3-pin)

Pin	Signal
1	BAT+ — raw battery voltage, about 2.5–3.65 V
2	PIR_OUT — same wake/gate signal as J3, enables the external boost
3	GND

J3 and J11 use the same pin order on purpose. Plugging one into the other's socket is harmless: the IR boost just sees 3.3 V, and the PIR sees a wider input range than it needs.

J6 — solar input (JST-XH, 2-pin)

Pin	Signal
1	SOLAR_IN (+)
2	GND

J10 — BME280 socket (2.54 mm, 4-pin)

Pin	Signal
1	VIN (3V3)
2	GND
3	SCL
4	SDA

This matches the pinout printed on common GY-BME280 breakout modules. I2C address 0x76.

J9 — antenna (u.FL)

Single-ended 50 Ω RF, straight to the RAK3172's antenna pad. Read the compliance section below before substituting an antenna.

GPIO map

The module's pins are almost entirely committed by the board design. This is the complete pin budget. There is no larger pool of free GPIO hiding elsewhere.

GPIO	Function
IO0	BOOT button
IO1	LoRa module reset (active low)
IO2	UART RX from LoRa module
IO3	Battery voltage sense (ADC, resistor-divided)
IO4	Camera SDA (sensor I2C)
IO5	Camera SCL (sensor I2C)
IO6	Camera VSYNC
IO7	Camera HREF
IO8	Camera Y4
IO9	Camera Y3
IO10	Camera Y5
IO11	Camera Y2
IO12	Camera Y6
IO13	Camera PCLK
IO14	UART TX to LoRa module
IO15	Camera XCLK
IO16	Camera Y9
IO17	Camera Y8
IO18	Camera Y7
IO19	USB D− (native USB: console + flashing)
IO20	USB D+
IO21	PIR wake input (deep-sleep wake source)
IO35–37	Not usable (internal octal PSRAM)
IO38	microSD DAT0
IO39	Camera power switch (active low, off by default)
IO40	BME280 SDA
IO41	BME280 SCL
IO42	LoRa module BOOT0 (module firmware-update mode select)
IO43	Free — the one clean spare digital GPIO on this board
IO44	Radio + microSD power switch (active low, off by default)
IO45	Not usable (module boot strap, flash voltage select)
IO46	Input only, with a caveat: it is a boot-mode strap and must read low during a BOOT-button flash. Fine for anything that reads low at reset.
IO47	microSD CLK
IO48	microSD CMD

Non-GPIO module pins: EN (reset) and 3V3/GND are broken out to the usual places, but not to a header.

The camera and LoRa-UART pins are fixed by the board. Reassigning them means routing a change nobody has validated. IO43 is the only pin free for a new purpose with no caveats, and IO46 works too if your use can tolerate reading low at reset.

Power tree

The board runs from a single 26650 LiFePO4 cell (3.2 V nominal), fitted in an on-board holder. There is no cell-swap connector.

Do not fit a Li-ion 26650

A Li-ion 26650 is 3.7 V nominal. The charge circuit on this board is built for LiFePO4's lower voltage and charging profile. A Li-ion cell in a LiFePO4 charger is a safety hazard, not just a spec mismatch.

Either USB-C (J1) or the solar input (J6) can charge the cell. USB does not power the board directly: it only feeds the charger. With no cell fitted, the board does not run on USB power alone.
Charging includes reverse-polarity protection and a thermal cutoff. Charging is inhibited below about 0 °C and above about 60 °C cell temperature.
The cell holder has its own reverse-insertion protection circuit, so an accidental backwards cell does not damage the board. It also will not run until the cell is reinserted correctly.

From the battery, three rails exist:

Always-on 3.3 V — the ESP32-S3, PIR and BME280. This is what deep sleep runs on.
Switched 3.3 V camera rail (IO39) — off by default; firmware enables it before a capture.
Switched 3.3 V radio + microSD rail (IO44) — off by default; firmware enables it to transmit or write to storage.

Charge status LEDs

Three LEDs, grouped at one board edge, give a charge readout without opening the enclosure. Four combinations are meaningful.

Input LED	CHG (red)	DONE (green)	Meaning
dark	dark	dark	No input reaching the board. Check the cable or charger.
lit	lit	dark	Charging normally.
lit	dark	lit	Full.
lit	dark	dark	The charger has declined to charge: out-of-window temperature, or a cell fault.

Compliance — antenna and radio firmware

The RAK3172's FCC grant covers full power (22 dBm) only with an antenna at or under 2.3 dBi gain on J9. The antenna MeshCam ships (Linx ANT-916-CW-HW, 1.2 dBi) is inside that limit. Swapping to a higher-gain antenna takes the board outside its certified operating conditions.

The LoRa module's own firmware cannot be modified by anyone but RAK. That is an FCC modular-certification rule, not a MeshCam restriction. The ESP32 side is fully open to custom firmware. The ESP32 to RAK3172 link is AT commands over UART (RAK's RUI3 firmware), which already exposes everything the product needs: frequency, bandwidth, spreading factor and TX power.

Mechanical

86 × 95 mm, four M4 mounting holes. If your enclosure has a conductive back panel, use nylon screws. The on-board cell holder's negative terminal runs close to two of the mounting holes, and nylon keeps that isolated.

Questions about the board, or something here that does not match the one in your hand? hello@getmeshcam.com.