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(Updated) Open source ESP32 module supports 5G and GPS connectivity

Mar 28, 2024 — by Giorgio Mendoza 310 views

CrowdSupply recently featured, the Walter embedded device equipped with the ESP32-S3 microcontroller along with a GM02SP module for NB-IoT, LTE-M and GPS protocols. The board is CE and FCC certified to accelerate customers’ product development.

Built around the ESP32-S3-WROOM-1-N16R2 microcontroller, Walter boasts an advanced core architecture and connectivity options. It features a Xtensa dual-core 32-bit LX7 CPU for robust processing, complemented by 16 MiB of quad SPI flash memory and 2 MiB of quad SPI PSRAM for ample storage and efficient operation.


Its connectivity capabilities include a 150 Mbps 802.11 b/g/n Wi-Fi 4 with an integrated PCB antenna, and a 2 Mbps Bluetooth 5 Low Energy, also with an on-board PCB antenna, ensuring reliable and fast wireless communication.

ESP32-S3 SoC block diagram
(click images to enlarge)

The Walter board offers up to 24 GPIOs and it also includes test points for debugging located on the opposite side of the board as shown below. 

Walter comparison table
(click image to enlarge)

According to the datasheet, the ESP32-S3 and the Sequans GM02SP module interface each other (UART0) using AT commands. The Walter board also seems to integrate a software-controllable MOSFET transistor to switch its peripheral power pin in case users need to remove attached devices as sensors or other external devices.

Engineered for efficiency, Walter achieves remarkable power conservation in deep sleep mode, crucial for battery-powered applications. It consumes a mere 9.8 µA – 8 µA for the ESP32-S3, 1 µA for the GM02SP, and 0.8 µA for the power converter. This design allows Walter to function over 34 years on a single 18650 cell, highlighting its long-term endurance in low-power scenarios.

Walter peripherals
(click images to enlarge)

DPTechnics has made comprehensive documentation available for their project, including schematics, footprints, and a detailed datasheet accessible on the CrowdSupply page. Additionally, there’s a GitHub repository for further resources. To assist users in understanding the board’s capabilities and potential applications in real-world scenarios, they also offer a webinar that covers its main features.

Specifications listed for the Walter board include: 

  • Connectivity: 
    • Cat M1 (Cat M1 up to 590 kbps DL & 1.1 Mbps UL)
    • Cat NB1/NB2 (up to 120.7 kbps DL and 160 kbps UL)
    • GPS, GNSS support
    • BLE 5.0, Bluetooth mesh (up to 2Mbps)
    • Wi-Fi 802.11/b/g/n (up to 150Mbps)
  • I/O Interfaces:
    • 24x GPIO pins
    • 3x Power pins, 1x Strapping pin
  • Other Features:
    • 23x Testing points for debugging
  • Software:
    • MicroPython
    • Arduino, ESP-IDF
    • JavaScript
  • Power:
    • 3.3V (via USB-C port or VIN-pin)
    • DC-DC Converter (TI LM3281YFQR)
  • Dimensions:
    • 55 x 24.8mm

The company introduced the Walter Feels Carrier Board, tailored to streamline the development of IoT prototypes. This board boasts a wide 3.1 – 35 V MPPT power input range, versatile battery charging for various chemistries and configurations, and operates with voltages down to 2.5 V.

It incorporates an I²C battery and power management system using the Analog Devices LTC4015, a MicroSD card slot, and integrated sensors for environmental data like temperature, humidity, and pressure, plus a 6 DoF IMU for motion detection.

Additionally, it offers a connection for a Sensirion SCD30 CO₂ sensor and supports multiple interfaces, including RS232, RS485, SDI-12, and CAN bus. With 3.3, 5, and 12 V outputs and two GPIO pins from the Walter board, it’s adaptable for various needs. The board is also compatible with Takachi PFF13-4-13W housing, ensuring its suitability for indoor environments.

Walter Feels carrier board
(click images to enlarge)

Further information

The standalone Walter module is priced at $70.00. For a more comprehensive setup, the Walter Development Kit, priced at $250.00, includes additional components such as antennas, a 250 MiB worldwide Soracom SIM card, a USB Type-A to Type-C cable, and a USB Type-C to Type-C cable. It also offers 30 minutes of expert support to assist in project initiation.

The Walter Feels carrier board is available for $99.00, but note that it does not include the Sensirion SCD30 absolute CO₂ sensor. These prices exclude shipping costs, with an estimated delivery date of September 30, 2024, for orders placed now.

For more information, see the product page on

(advertise here)

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