Make the Most of Your ESP32-S3 Walter with Soracom Connectivity

Walter Feels, ESP32-S3, IoT Module

An IoT project is only as capable as the technologies it relies upon, which is why choosing the right microcontroller board is so important. To this end, the team at DPTechnics has introduced a powerful new IoT module that combines the reliably secure ESP32-S3 with the power optimization of Sequans Monarch 2 cellular modem.

Dubbed the Walter, this CE and FCC-certified module has the potential to revolutionize the IoT development game. Let’s take a look at what makes the Walter tick.

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What is the ESP32-S3 Walter?

The ESP32-S3 Walter is a low-cost, low-power microcontroller with integrated WiFi and Bluetooth 5 (LE) capabilities. Its unique architecture affords Walter an array of wireless connectivity options – including Cat-M1 (LTE-M), GNSS, and NB-IoT – all within a compact device that can easily accommodate virtually any use case.

Designed and built in Belgium, the Walter looks to be an IoT developer’s new best friend by providing a versatile module that allows developers to deploy reliable low-cost, low-power, high-efficiency devices with a low footprint and at a reasonable cost.

Why Select Walter?

One of the key features of the Walter is that it is open source. The board’s schematics will be released under GPLv3 License and will support a bevy of software from Espressif IDF, Arduino ecoSystem, Micropython, Toit, and more libraries. DPTechnics makes its documentation readily available here and encourages suggestions and contributions from users to create the most versatile product possible.

This versatility extends to the device’s 28 I/O pins, which allows users to utilize virtually any peripheral devices with the microcontroller, from I2C to SPI to UART and more. These can be multiplexed to any pin on the Walter, allowing the freedom to expand and control the physical layout of your deployment more intrinsically, this makes the Walter backward compatible with older Pycom devices but also allows developers to optimize the routing of the carrier board.

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There is even an expansion board dubbed the Walter Feels that opens up the possibilities of even further peripheral integrations. This includes an extensive power management setup that allows for the usage of renewable energy sources, integrated sensors for things like temperature and barometric pressure as well as an endemic gyroscope, and an included battery that operates on as little as 2.5 volts.

That only scratches the surface of the Walter’s commitment to low-power and high efficiency, as its upgraded chipsets allow for the Walter to run a lower sleep current (only 9.8uA) during inactive states than its contemporaries. Walter also features a 3.3-volt output that can be managed via software controls, meaning that even if you are attaching the board to power-hungry peripherals (i.e. industrial sensors) that are not designed with sleep modes, you can effectively turn them off via software to better manage your power usage.

Who Should Use the ESP32-S3 Walter?

With its versatility and low power consumption, Walter is a great tool for developers in the testing stage. The ability to utilize virtually any peripheral and the open-source nature of the product makes Walter the perfect launch pad for new and innovative ideas. Yet it need not be confined to small installations or hobbyists. Several organizations have begun testing with the board and found it appropriate for low-medium product volumes in areas where a more advanced custom solution is perhaps too expensive.

With its lower power requirements and utilization of LPWAN connectivity, Walter is ideal for asset tracking. The board already features a built-in GNSS receiver and comes pre-flashed with tracking firmware, meaning you don’t even need a carrier board. Users recently deployed Walters for this purpose on small fishing boats in Cyprus, and it proved an easy tracking solution without the need for costly antenna equipment.

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Similarly, the Walter has been deployed to monitor remote weather stations in the North Sea. This user utilized underwater sensors to monitor conditions in the sea that communicated through a Modbus connection making it a natural fit for the Walter Feels’ RS4-85 ports. This installation is also unique in that it took place comfortably out of range for most cellular providers, though Soracom’s LTE-m solution allowed the device to communicate seamlessly throughout the Proof of Concept stage.

Walter has even been deployed two stories below ground in a tank-level monitoring solution in Belgium. In this case, the customer was actually upgrading to the Walter from an older device to take advantage of its LTE capabilities, proving that not only could the device connect indoors, but underground.

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How Does Soracom Fit In?

As a connectivity partner, Soracom helps unlock the potential of Walter by making the most of its low-power capabilities. Soracom hosts a number of LPWAN technologies and connects customers to the top carriers across the globe. 

Soracom also features a number of tools to help manage and control a device’s power output and usage through its IoT platform and API controls. From the ability to throttle the speed of a SIM to customizable alerts when a device reaches a predetermined threshold, Soracom puts the user in charge of their deployment at a granular level – something that drew DPTechnics to work with Soracom in the first place.

“As a developer, you need to zoom in on power consumption,” said Daan Pape, owner of DPTechnics. “That’s one of the main reasons we partnered with Soracom, as PSM and EDRX are so important to this cellular technology and you need to have good control also from the operator side to get your power consumption as low as possible.”


There is an ongoing crowd-funding campaign for Walter on Crowd Supply to further its development. If you are interested in learning more about the device – or perhaps even contributing to it – you can do so here.

Want to learn more about how Walter and Soracom work together? Check out our recent webinar, where DPTechnics’ own Daan Pape speaks with us about this exciting new development in connected technologies.