node-red-contrib-sensor-consensus

A Node-RED sensor-fusion / consensus node. Readings from multiple sensors (keyed by msg.topic) are fused into a single trusted aggregate, and a trigger latches when that aggregate crosses a configured threshold — with freshness (staleness windows), quorum, and disagreement detection as first-class features rather than afterthoughts.

Averaging three healthy humidity sensors is easy. What existing aggregation nodes don't answer is what happens when one of them goes quiet, sticks, or drifts: a dead sensor's last reading silently skews the average forever, and nothing tells you a trigger didn't fire because trust was lost rather than because the value was fine. This node makes every one of those decisions observable.

Highlights

• Two type modes (per node instance): Numeric — mean, median, min, max, or trimmed mean over the latest value from each source — or Boolean — vote rules (Any / Majority / All / At least N) over the fraction of sources reporting true, with configurable true/false value lists.
• Trust built in: per-source staleness windows, fresh-source quorum, minority reports when a sensor disagrees with its peers, and a configurable Hold/Release policy for quorum loss while triggered.
• Latched threshold trigger with direction (above/below) and hysteresis, plus runtime commands to move thresholds, adjust the staleness window, disable/enable decisions, and remove or reset sources.
• Four purpose-built outputs — Trigger, Release, Query, Events — where outputs 1 and 2 carry only what genuinely happened, and every blocked, rejected, or suppressed action is observable on the Events output with msg.ignored = true.
• Heartbeat snapshots for watchdogs, and optional persistence across deploys/restarts with wall-clock staleness re-evaluation on restore.

Install

From the Node-RED palette manager, or:

cd ~/.node-red
npm install node-red-contrib-sensor-consensus

Documentation

The embedded node help (in the editor sidebar) is a complete reference. Detailed documentation, examples, and troubleshooting live in the project wiki. The authoritative record of design decisions is sensor-consensus-design.md in this repository.

Sibling nodes

This node shares its event envelope (msg.ignored, msg.source), command conventions, and output-exclusivity guarantees with node-red-contrib-timer-events and node-red-contrib-timer-threshold — downstream flows can process events from all three with the same code.

Testing

npm test

runs the standalone assertion harness (no framework dependencies; 144 checks across 8 suites at the time of writing). Publishing is gated on the same harness via prepublishOnly.

License

Apache-2.0. Includes Douglas Crockford's public-domain cycle.js for persistence serialization.