LTE Cat 1 Pi HAT

Seeed’s LTE CAT.1 Pi HAT is an open sourcecellular extension modem for Raspberry Pi, based on u-blox LARA-R2xx series. Itcompatible with Raspberry Pi 1 Model B+ and later versions.

LTE CAT.1 Pi HAT is designed for LTE Category 1 networks and with 2G fallback(EU version only). Embedding common protocols, like TCP/UDP, HTTP.

LTE CAT.1 Pi HAT supports UART and USB interfaces. By UART, Raspberry Pi communicate with LTE CAT.1 Pi HAT via AT command without any special driver. It’s well suited for building prototyping rapidly.

Version Links





Product Version Changes Released Date
LTE Cat 1 Pi HAT(USA-AT&T) Initial Dec 2017
LTE Cat 1 Pi HAT(USA-VZW) Initial Dec 2017
LTE Cat 1 Pi HAT(Europe) Initial Dec 2017


  • Compatible with Raspberry Pi 1 Model B+ and later versions

  • LTE CAT.1 and support 2G fallback(EU version only)

  • UART and USB interface for communicate

  • Support Grove I2C and Digital connector

  • Protocols on cellular module

  • Embed TCP/UDP stack

  • Embed HTTP, FTP, SSL

  • Dual stack IPV4/IPV6

  • 3GPP TS 27.007 [8], TS 27.005 [9]standard AT command


  • IoT gateway
  • Data logger
  • Vending machine
  • POS
  • Smart home devices
  • Robot
  • Advertising
  • Other scenario need cellular networks

Hardware Overview


  • LTE CAT.1: U-blox LARA-R2xx series LTE CAT.1 module, please refer to u-blox LARA-R2 series product page for more information.
  • Grove Port: 2 Grove I2C/Digital Port, connected to SDA_RPI, SCL_RPI, it can be used as I2C or GPIO port.
  • Switcher: Control Grove port voltage as 5V or 3.3V
  • USB Interface: It can be used to power up the LTE Cat.1 Pi HAT and raspberry together, and used for debug port as well. Please refer to FAQ Q1 about how to use as debug port.
  • Battery Holder: MP2617 is used for battery power management. If the battery is not connected, the CHG led will flash by 6HZ frequency. It will be off when under charging and on when finish charging. The connector is JST2.0 standard.
  • Lara-R2XX Reset button: Reset Lara-R2xx module.
  • Lara-R2XX Power on button: Press 2 seconds to power on the Lara-R2xx module.
  • Antenna: It includes 2 antennas, one is main and other is div. The main antenna is used for both sending and receiving signals. It must be connected. The div antenna is used for the receving only and to improve receiver sensitivity. It is optional.
  • Rpi 40 pins: Refer to pinout.
  • SIM card slot: Follow silk screen direction to plug LTE SIM card.


For the battery, we suggest 3.7V Li-ion battery and connect to JST2.0. Especially for Lara-R211(Europe) Pi HAT, it includes the GSM function with high power consumption. If there is no LTE signal around, the LTE CAT.1 Pi HAT also consumes a lot of power supply. So we highly suggest attach the battery.


Pin Used Python (BCM) WiringPi GPIO Name P1 Pin Number Name WiringPi GPIO Python (BCM) Pin Used
3V3_RPI 3.3v DC Power 1 2 5v DC Power 5V_RPI
SDA_RPI 8 GPIO02 (SDA1, I2C) 3 4 5v DC Power 5V_RPI
SCL_RPI 9 GPIO03 (SCL1, I2C) 5 6 Ground GND
FREE 4 7 GPIO04 7 8 GPIO14 (TXD0) 15 TX_RPI
GND Ground 9 10 GPIO15 (RXD0) 16 RX_RPI
RTS_RPI 17 0 GPIO17 11 12 GPIO18 1 18 FREE
FREE 27 2 GPIO27 13 14 Ground GND
FREE 22 3 GPIO22 15 16 GPIO23 4 23 FREE
3V3_RPI 3.3v DC Power 17 18 GPIO24 5 24 FREE
FREE 12 GPIO10 (SPI0_MOSI) 19 20 Ground GND
FREE 13 GPIO09 (SPI0_MISO) 21 22 GPIO25 6 25 FREE
FREE 14 GPIO11 (SPI0 SCLK) 23 24 GPIO08 (SPI0_CS0) 10 FREE
GND Ground 25 26 GPIO07 (SPI0_CS1) 11 FREE
FREE 30 Reserved 27 28 Reserved 31 FREE
LARA_PWR 5 21 GPIO05 29 30 Ground GND
LARA_RST 6 22 GPIO06 31 32 GPIO12 26 12 FREE
FREE 13 23 GPIO13 33 34 Ground GND
FREE 19 24 GPIO19(SPI1 MISO) 35 36 GPIO16(SPI1 CS0) 27 16 CTS_RPI
FREE 26 25 GPIO26 37 38 GPIO20(SPI1 MOSI) 28 20 FREE
GND Ground 39 40 GPIO21(SPI1 SCLK) 29 21 FREE



Now we have made three versions of the LTE Cat 1 Pi HAT. In addition to supporting different networks, they are almost the same. And you may pay attention that the only the Europe version support 2G net.

Version Module Network
Europe LARA-R211 2G/4G

Getting Started



We use the Raspberry Pi3 with 2018-04-18 RASPBIAN STRETCH WITH DESKTOP for below demo.

  • Step 1. Stack LTE Cat 1 Pi HAT on top of Raspberrry and connect the 2 antennas.

  • Step 2. Connect the mouse, keyboard and monitor as well.
  • Step 3. Power the Raspberry Pi.


  • Step 1. Use dtoverlay=pi3-disable-bt to enable Raspberry Pi3 UART0.
sudo nano /boot/config.txt

Then add dtoverlay=pi3-disable-bt to bottom of the config.txt

  • Step 2. Disable the system serivce to use the UART0.
sudo systemctl disable hciuart 


Pi3-disable-bt disables the Bluetooth device and restores UART0/ttyAMA0 to GPIOs 14 and 15. It is also necessary to disable the system service that initialises the modem so it doesn't use the UART: sudo systemctl disable hciuart.

  • Step 3. Delete the console=serial0,115200 in cmdline.txt.
sudo nano /boot/cmdline.txt

Then delete console=serial0,115200 from the string.

  • Step 4. Reboot the Raspberry Pi3
sudo reboot
  • Step 5. Run below commands to run the demo
cd ~
git clone https://github.com/Seeed-Studio/ublox_lara_r2_pi_hat.git
cd ublox_lara_r2_pi_hat
sudo python setup.py install
cd test
sudo python test01.py
  • Step 6. Here is the output from terminal.
pi@raspberrypi:~/Desktop/ublox_lara_r2_pi_hat/examples $ sudo python test01.py
40-pin GPIO header detected
Enabling CTS0 and RTS0 on GPIOs 16 and 17
rts cts on
waking up...
module name:  LARA-R211
RSSI:  3


Q1: Can we communicate with LTE Cat 1 Pi HAT directly with PC?

A1: Yes, there are 2 ways. One is USB and other is UART port.

  • For the UART port, Please use the usb to serial adaptor, follow below connection and use the baudrate as 115200. We can use any Serial COM monitor tool to run AT commands.
USB to UART Adaptor LTE Cat1 Pi HAT
NA Pin11-RTS_RPI Connect to Pin9-GND


Please do connect the RTS_RPI to GND as marked as red at above picture if we use the UART port for communication.

Q2: Do you have AT command list?

A2: Here is u-blox-CEL_ATCommands.

Q3: What is differences between the Lara-R203/204/211?

A3: Please refer to u-blox LARA-R2 series product page.


Tech Support

Please do not hesitate to contact techsupport@seeed.cc if you have any technical issue. Or submit the issue into our forum.