Observer Nodes
| D-Cube makes use of several Raspberry Pi 3 nodes, each connected to a custom add-on card, as unobtrusive observer nodes to measure the reliability, latency, and energy-efficiency of IoT protocols running on a given target platform.
Each observer, which is powered by PoE and connected via Ethernet to a central server, is completely agnostic to the hardware platform chosen as a target, as long as the latter can be connected via USB to the custom add-on card. |
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| The custom add-on card connected to the Raspberry Pi 3 embeds a power and latency profiling unit, as well as a GPIO tracing unit. The power profiling unit captures voltage and current using a 125 kHz simultaneous-sampling 12-bit current and voltage ADC.
The GPIO tracing and latency profiling units allow simultaneous tracing and actuation of up to 8 GPIO pins per target platform. Observer nodes equipped with a GPS unit can generate precise timestamps for externally triggered events. Nodes without direct GPS connectivity can synchronize to the rest of the network using NTP with a typical accuracy well below 10μs. Target nodes can be individually powered on/off in software, hence allowing to control the network density and to emulate node failures (e.g., due to an early battery depletion) by software. |
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Under construction.