Spine Doctor

Mission

Build this

Build a physical clinic that tracks expected periodic evidence from selected nodes, separates late from silent, and raises one calm flag for a documented outage.

Bill of materials

Parts

Disconnect USB before rewiring. Motors, the relay, and the servo need appropriate power and a shared ground. Never drive an actuator from the ESP32 3V3 pin.

The central idea

Online, fresh, and correct are three different claims

Your required claim is freshness for selected periodic topics. Status messages provide useful context, but because many publish only when state changes, silence on status alone is not evidence of failure.

Write the care plan

Every monitored device deserves its own clock

Wiring

Build a calm clinic, not a permanent alarm

Show monitored devices and message ages on the OLED before adding the flag. Use colour and one brief sound only when the overall state changes; repeated beeping does not improve diagnosis.

The power rule: The OLED, RGB logic, and verified buzzer module use 3V3. Each LED colour needs 220 Ω. The servo uses a separate 5 V supply. Join all grounds.

Give silence a fair trial

Late should come before silent

Your controlled outage ward

Break one known connection at a time

1. Collect a healthy baseline.

   Run the selected devices through enough expected intervals to measure ordinary message delay and occasional gaps.

2. Schedule short and long outages.

   With the owning team present, disconnect one test device for durations below and above its thresholds.

3. Record the complete response.

   Measure late detection, silent detection, false alarms on other nodes, and recovery after the first valid message.

4. Repeat after one rule change.

   Use the same outage script so lower false alarms cannot hide a much slower diagnosis.

When the doctor misdiagnoses the garden

Disagreement tells you which health model you built

Choose your systems question

What kind of Doctor team will you become?

A calm way through the build

Collect four small wins

1. sd-01 says hello.

   Prove the monitor can report its own status first.

2. One periodic topic shows a growing message age.

   Record arrival time without using a blocking timer.

3. One short outage becomes late, not dead.

   Add grace and a patient-specific silence threshold.

4. One long outage and recovery move the flag once each.

   Add the remaining patients, then run the fixed script.

The garden handshake

Share what you found

These names are the rigid part of the project. They let another team find your work without knowing what you called the variables in your code.

Finish line

Ready to introduce to the garden

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  sd-01 stays online and publishes fresh-node count every minute plus a registered monitor status.

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  The reject feed stays clear after the final code starts.

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  Each monitored node has a documented periodic evidence topic, expected interval, grace, and silence threshold; on-change status is not treated as heartbeat.

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  Display, light, brief cue, and flag derive from one patient table without blocking messages or repeating alarms.

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  The build log contains a healthy baseline, planned short and long outages, late and silent detection delays, recovery time, false alarms, and a repeated script after one change.

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  The monitor distinguishes its own network failure from patient silence, the servo is safely powered, sound is restrained, and the label can be scanned.

Spine Doctor is trustworthy when its alarm names the evidence it lost, the clock it expected, and the limits of the diagnosis—not merely the device it suspects.