ModBee Hats

Expansion hats for the ModBee Node-UIO, an ESP32-S3 industrial I/O module for 35 mm DIN rail. A hat plugs onto the Node-UIO's two 8-pin hat headers and adds cellular, LoRa mesh or mains power.

This repository holds the hardware documentation for each hat: schematics (PDF), 3D renders and a README covering connections, configuration and first use.

Hats

Hat	Module	What it adds
CAT	SIMCom SIM7070G	LTE Cat-M1 / NB-IoT with GPRS/EDGE fallback, GNSS
LTE	SIMCom A7670G	LTE Cat-1 with GSM/GPRS/EDGE fallback. GNSS on module variants that include it
LoRa Mesh	Ebyte E52-900NW22S	Self-routing LoRa mesh radio, bridged to RS485 or UART
PS AC/DC	Isolated 20 W AC-DC module	85–500 VAC / 100–700 VDC in, 24 VDC 800 mA out

Hat connector

Every hat uses the same two 8-pin, 2.54 mm headers. They match headers J6 and J7 on the Node-UIO. Fit stacking headers with 8.5–11 mm pins so a hat seats fully on the board below it.

Pin	Signal	Node-UIO connection
1	+3.3V	Node-UIO 3.3 V rail (labelled +3.3VIN on the hat schematics)
2	GND	Ground
3	SCL_1	I2C bus 1 clock, GPIO47
4	SDA_1	I2C bus 1 data, GPIO48
5	U0RX	UART0 receive, GPIO44 (ESP32-S3 input)
6	U0TX	UART0 transmit, GPIO43 (ESP32-S3 output)
7	GPIO9	Hat power enable
8	GPIO10	General purpose; cellular hats use it for the module power key

Pin	Signal	Node-UIO connection
1	V_Supply_F	External 5–24 V supply after the Node-UIO input fuse
2	GND	Ground
3	V_IN	Node-UIO supply input, ahead of its fuse. A hat can feed power in here
4	RS485_A_0	RS485 CH1 A (UART1)
5	RS485_B_0	RS485 CH1 B (UART1)
6	RS485_A_1	RS485 CH2 A (UART2)
7	RS485_B_1	RS485 CH2 B (UART2)
8	WIFI_EN	Node-UIO Wi-Fi button line, GPIO40

The I2C bus on the hat header (GPIO47/48) is separate from the Node-UIO's on-board ADC and DAC bus (GPIO37/38).

Hat power switching

The CAT, LTE and LoRa Mesh hats run from a local 3.3 V rail that a P-channel MOSFET switches from the Node-UIO's 3.3 V. Drive GPIO9 high to power the hat and low to turn it off. To keep a hat powered all the time, bridge its bypass solder jumper (JP1 on the cellular hats, JP6 on the LoRa Mesh hat).

The PS AC/DC hat is a power source, not a load, and does not use GPIO9.

Stacking hats

Hats can be stacked, but they share header signals. Before you combine hats, check what each one uses:

Signal	CAT	LTE	LoRa Mesh	PS AC/DC
GPIO9 (power enable)	yes	yes	yes	–
GPIO10 (power key)	yes	yes	–	–
U0RX / U0TX	yes	yes	only with JP1/JP2 bridged	–
RS485 CH1 or CH2	–	–	yes (default, CH1)	–
V_IN	–	–	–	feeds 24 V in

Fit only one cellular hat. CAT and LTE both use UART0 and GPIO10.
A cellular hat and a LoRa Mesh hat can share a stack while the LoRa hat uses RS485 (its default). Both switch on and off together from GPIO9.
Every hat on GPIO9 switches together. Use a hat's bypass jumper if it must stay on.

Repository layout

modbee-hat-<name>/
  README.md      specifications, connections, configuration, getting started
  schematics/    schematic PDF exported from KiCad
  images/        3D renders of the board

The images are 3D renders. Placeholder 3D models can carry markings that differ from the parts fitted to the board. The schematic is the reference.

Licence

The schematics, images and documentation in this repository are licensed under Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0). You may share and adapt them, including commercially, if you credit ModBee and release adaptations under the same licence.

SIMCom, Ebyte and other product names belong to their respective owners. Manufacturer datasheets and manuals are not redistributed here. Each hat README links to the official source.

HATs