Walter Packs 5G, Wi-Fi, Bluetooth, and GNSS Into a Certified Board as Short as a AA Battery

DPTechnics has launched the Crowd Supply campaign for Walter, a certified wireless module that packs Wi-Fi, Bluetooth, LTE-M/NB-IoT, and GNSS into a relatively small board.

About a year ago, we had our first introduction to Walter, a system-on-module (SoM) measures only 24.8 by 55 millimeters. On board are a Esspresif ESP32-S3 and a Sequans GM02SP. The ESP32 has a dual-core application processor and a 2.4 GHz radio with an integrated antenna for Wi-Fi and Bluetooth. The GM02SP contains a network processor and radios to cover cellular communication and receive GPS / GNSS positioning with external antennas.

Overall, Walter is only slightly larger than the area taken up by the two modules, two u.FL antenna connectors, and a USB-C port. The backside features 2.54 millimeter header pins, providing access to 24 GPIOs and 22 test pads to assist with production programming and testing. You can also find a Nano SIM Slot on the backside.

DPTechnics says it has library support for Walter's hardware, which is available for the Espsressif ESP-IDF, Arduino IDE, MicroPython, and Toit. Their library uses an AT command set that leaves the ESP32's processor load very low. Additionally, for network communication, the libraries offload protocol work to the network processor in the Sequans GM02SP.

Walter's current consumption when in deep sleep is a scant 9.8 microamps! While the SoM does not contain a battery circuit, it does have one peripheral power-saving feature. A GPIO pin controls the 3 volt supply pin. This feature allows you to power down external sensors when the ESP32 goes to sleep.

Several features set Walter apart from other IoT rapid prototyping boards. Walter is rated for an industrial temperature range of -40°C to +85°C and will have FCC, CE, UKCA, IC, and RCM (for Australia and New Zealand) certifications. DPTechnics has negotiated contracts with its component suppliers to ensure guaranteed availability for a minimum of ten years.

Edit: On April 8,2024, DPTechnics sent an email update to announce all certification tests are completed and passed!
"This confirms that Walter's design is sound and the CE, FCC, UKCA, IC and RCM markings are well deserved."

In addition to the SoM board, DPTechnics now has a development carrier board called Water Feels. This carrier provides a Solar MPPT, battery charger, power management, environmental sensors, and more. It is compatible with an off-the-shelf Takachi PFF series enclosure that is suitable for indoor applications.

Since our last look at Walter, DPTechnics has added extensive documentation to fulfill its open source promise. The Walter-Hardware GitHub repository contains design files, renders, schematics, and datasheets. For example, DPTechnics provides a PDF of the schematic and a KiCad footprint for the Walter module.

There are three products available in the already funded Walter Crowd Supply campaign. The standalone Walter SoM is $70. A Walter Devkit is a 250 USD bundle with the SoM, cables, antennas, and 250 MB Worldwide SIM card. Last, the Water Feels carrier board is priced at 99 USD. The campaign is live now. DPTechnics expects shipments to occur by September 30, 2024.