This demo shows how to send fully end-to-end encrypted images from the Cloud through a gateway and finally over Bluetooth connections to small devices with screens. This was prototyped in a few days and showcased by Golioth Design Partner AL2Tech at Embedded World 2026. Founder and CEO Andrea Longobardi demonstrates in the video below.
An image is just a binary
Golioth’s cloud infrastructure regularly deliveries binaries to embedded devices: Over-The-Air Firmware updates are binaries pushed into memory for reloading a new version after reboot. We also support block downloads of other binaries including images, audio, Machine Learning (ML) models, and more.
Directly connected devices (Cellular, Wi-Fi, Ethernet) use the Golioth Firmware SDK, often using the Zephyr RTOS port to interface to a variety of supported hardware platforms. Indirectly connected devices (Bluetooth) use the Pouch SDK, also built on top of Zephyr. Andrea (explaining the demo) and Alessandro (seen waving in the transmitted photo) built super low power consumption devices with the Nordic Semiconductor nRF54L15, a battery controller, and a screen. These are intended to work off of batteries for a long time, drawing only 30 uA of current in passive mode (still advertising and reachable over Bluetooth) and low mA of current in active transmit/receive.
How the information moves down to the Bluetooth device
In the demo video above, Andrea takes a photo of Alessandro, uses their app to upload the photo to Golioth (using an API key), and then the photo is available on the cloud. This JPEG image is an artifact that is available to devices within the same cohort. As each Bluetooth device wakes out of sleep every 10 seconds, it checks in with the gateway to both send up any available data, and see if there are any settings or manifest changes. If there are, the blockwise download of images starts on the Bluetooth device.
Each is individually end-to-end encrypted with the cloud, and there are no shared keys. The gateway–based on the FRDM-RW612 in this scenario–is not able to see the content of the packets being sent through the gateway because the Bluetooth device has keys to the Cloud and the gateway does not. After the image is finished downloading, the new image pops up on the display for that device.
Making Bluetooth devices into Internet devices
The Pouch protocol makes it easy for devices that aren’t normally connected to the internet to still interact with the Cloud. Encrypting individual packets with the cloud without needing any particular gateway interaction enables interesting capabilities like roaming between different gateways and also allows future indirectly connected devices that are using different transport mechanisms like CAN, RS485, and Serial.
Read about how our Bluetooth offering has increased over the past year and get started building your own application on top of Golioth today.
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