No network cable in the room? MOBOTIX ONE sensors can run on DC power alone and process events locally. Using c ONE NurseAssist as an example, we explain when this makes sense and its limits.
What is DC-only operation?
MOBOTIX ONE sensors can operate as autonomous edge devices without a permanent IP network connection. The sensor is commissioned via Ethernet as usual. Afterwards, the network cable is disconnected and the sensor is powered solely through its external 12–24 V DC input, while event detection, evaluation and the resulting actions continue locally on the sensor.
Two reasons to choose DC-only operation
Existing buildings without network cabling
In new buildings, a network connection in every room can be a standard. In existing buildings it often is not, and retrofitting it can be expensive, disruptive or simply impossible. Structural constraints, fire-safety requirements for wall penetrations, heritage protection or rooms that remain occupied during the work can all stand in the way.
Mains power, by contrast, is available in practically every room. DC-only operation makes use of this: with a suitable 12–24 V DC power supply, a MOBOTIX ONE sensor can be installed where no network cable can be laid.
Privacy by design
Disconnecting the network cable also creates a clear technical boundary between the video sensor and the IP network. Network-based access to the sensor and transmission of video data are prevented physically, not just by software settings. This supports the GDPR principle of data protection by design and by default (Article 25) wherever minimal connectivity and local processing are explicit design goals.
Commissioning: configure first, then disconnect
During commissioning via Ethernet, the installer configures everything the camera needs to work on its own: image settings, camera-internal event sources and logic, event conditions and filters, Action Groups and their actions, local signalling and the behaviour of the relais output. Once the configuration is stored on the sensor, the cable is removed.
Later configuration changes require a temporary network connection, for example a laptop connected on site. We therefore recommend testing the complete event chain before disconnecting.
Detect, evaluate, act: everything stays on the ONE
In DC-only mode, the entire processing chain runs locally, so Action Groups need to be based on sensor-internal or locally available event sources. Depending on the model, a detected event can trigger the integrated white light, the RGB LED, the integrated or an external speaker, or the relais output for external signalling (Up to 5 relay outputs in total with an additional 4IO interface box), automation or alarm equipment.
Functions that depend on other network devices or services are not available while the sensor is disconnected. These include notifications to remote systems, MQTT or API integrations and access via video management software.
Example: c ONE NurseAssist in an existing care facility
On c ONE NurseAssist, the NurseAssist analytics run locally on the sensor and do not require video recording. Events such as a detected fall are available on the sensor as internal events that Action Groups can use.
Where a wired nurse call or light-signal system is already installed, the relais output (a potential-free contact) can pass a NurseAssist event to an input of these systems. By using an additional 4IO interface box, up to 5 individual NurseAssist alarm types can be transmitted this way. In the room itself, the prepared emergency light workflow can switch on the integrated white light when a fall is detected at night. This workflow is disabled by default and is activated as part of the facility’s processes.
The trade-offs need to be planned for. MOBOTIX HUB with the NurseAssist Dashboard, network-based nurse call integration, intercom and remote status monitoring are not available. Because the sensor cannot report its own status, the facility should define how sensor availability is checked in daily operation. On the hardware side, plan a suitable 12–24 V DC supply installed by a qualified electrician, and note that the I/O terminal block (Mx-ONE-A-IO-c1) is ordered separately.
No automatic GDPR compliance
DC-only operation supports a privacy-oriented deployment, but it does not guarantee GDPR compliance. Compliance depends on the complete application and system configuration, including the purpose of the processing, whether images are recorded and stored on the sensor, retention periods, the legal basis, information provided to the people concerned and the physical protection of the device. Data stored locally remains personal data, and responsibility for this assessment lies with the operating organisation.
FAQ
Is DC-only operation limited to NurseAssist? No. It is a feature of the MOBOTIX ONE platform and suits any application in which local detection and local responses are sufficient.
Can a DC-only installation be connected to the network later? Yes. If network cabling becomes available, for example during a later renovation, the sensor can be connected and network-based functions configured. A project can therefore start before the infrastructure is complete.
How does this differ from disabling network functions in software? Software settings can be changed via the network. A physically disconnected cable prevents network access at the infrastructure level, regardless of how the sensor is configured.
Conclusion
DC-only operation turns a MOBOTIX ONE sensor into a self-contained edge device that needs nothing but power. In existing buildings, this can enable projects that would otherwise fail at the cabling stage, and physical network isolation adds a strong privacy-by-design building block. The key is planning: design around local events and actions, and clarify interfaces such as nurse call inputs early.
Sources
- MOBOTIX c ONE NurseAssist – Technical Specifications
- Regulation (EU) 2016/679 (GDPR), in particular Article 25 on data protection by design and by default
- EDPB Guidelines 3/2019 on processing of personal data through video devices
This article provides general technical and regulatory information, not legal advice. Applicable requirements depend on the specific use case and legal context.