Walter, an open-source, fully certified multi-radio (LTE Cat-M1, LTE Cat-NB1/2, WiFi, Bluetooth, GNSS) module

Walter is a small-form-factor IoT system-on-module (SoM) that combines a powerful ESP32-S3 system-on-chip (SoC) with a second-generation Sequans GM02SP LTE-M/NB-IoT 5G modem and GNSS receiver. Its ESP32-S3 provides many built-in peripherals as well, including UART, SPI, I²C, CAN, Wi-Fi b/g/n, and Bluetooth 5. Walter is the only module that packs all of these connectivity options into such a small package. While ideal for prototyping you can also use Walter for production as it is fully certified (CE, UKCA, FCC, IC, RCM).

Open Hardware Powered by Open-Source Software

Walter comes with a range of fully open-source software libraries so you can jumpstart your 5G IoT project in minutes using your preferred languages and toolchains. It supports ESP-IDF, Arduino, MicroPython, and Toit. No special dongles are needed to program Walter – just connect it directly to your dev machine using a regular USB Type-C cable.

Our embedded-software team is continuously improving Walter’s open-source libraries, which you can find in our GitHub repo. These libraries are optimized for flexibility and ease-of-use, with a particular emphasis on:

Low power: Ours is the only open source AT command library that uses condition variables instead of active wait, which keeps the load on the ESP32 processor extremely low.Transparent protocol offloading: Other solutions use the modem purely as a data source and sink, which means high-level protocols—such as CoAP, MQTT, HTTP and their secure TLS or DTLS variants—are all handled in the host processor. This not only consumes a lot of memory, it also decreases efficiency. Our libraries offload these protocols to the Sequans GM02SP modem, on which they have been tested by millions of users.Error handling: Cellular communication can fail in various ways, and good error handling is essential for product reliability. Our libraries provide extensive error handling to help you acquire and maintain a reliable cellular connection.Easy integration: We will continue maintaining, improving, and expanding our libraries throughout the lifetime of Walter. That includes a wide range of sample projects designed to get you up and running as quickly as possible.More Than a Development Board

Evolving a prototype into a commercial offering is the most daunting stage of product development. Walter aims to reduce this complexity, especially for low- to medium-volume production. It is the perfect entry point for businesses looking to develop their own 5G connected IoT products.

First of all, you will find no unnecessary components on Walter. There are no sensors, no RGB LEDs, and no charging circuits, to name just a few intentional omissions. Each of these "features" would have increased Walter’s cost while sitting unused most of the time for most applications. Instead, you will find a number of test pads, on the bottom of the board, which can be used to automate firmware flashing and product testing.

Secondly, we have certified Walter for FCC, CE, UKCA, IC, and RCM (for Australia and New-Zealand). Unless you add another radio to your Walter-based product, your certification costs and risks will be minimal. You can download all test reports by looking up the FCC ID 2BDGUWALTER.

Reliable, long-term support is essential for IoT products, so we have negotiated contracts with our component suppliers that allow us to guarantee availability for a minimum of ten years.

Walter is only 24.8 x 55 mm, so it will fit in just about any product. In fact, we’re not aware of any possible way to make a smaller standalone board with support for these RF technologies.

Ultra Low-Power Deep Sleep

For many battery-powered applications, Walter will spend most of its time in deep sleep. It is therefore critical that we consume as little power as possible in this mode, which was among our key requirements during the design stage. We are extremely proud of the result and have validated that Walter only consumes 9.8 µA in deep sleep mode.