Compare a motion event with an environmental value

Separate a changing simulated temperature value from a short motion event and the gateway siren alert driven by that event.

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Predict the reading, then compare it with the measurement.

Cisco Packet Tracer

Desktop lab

Separate a changing simulated temperature value from a short motion event and the gateway siren alert driven by that event.

Tier 3 · Install required · Cisco account required

Version tested: Cisco Packet Tracer 9.0.1 on Ubuntu 22.04 (Apptainer/Xvfb); saved project reopened and execution captured 2026-10-09. Date: 2026-10-09.

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Steps

Screens captured against Cisco Packet Tracer Cisco Packet Tracer 9.0.1 on Ubuntu 22.04 (Apptainer/Xvfb); saved project reopened and execution captured 2026-10-09 on 2026-10-09; the tool may have moved on — the text steps are the contract.

  1. Step 1

    Do
    Open lab.pkt in the Logical workspace. Locate Home Gateway0 and wired PC0. Find Temp-Monitor, Motion-Event, and Siren-Alert. Keep the three Things and gateway in view.
    You will see
    The gateway and PC are on the left. Three named Things are on the right. Their wireless links lead to the gateway. The siren is a separate output device.
    Why it matters
    The topology separates measurement, event, and action. Temp-Monitor supplies a numerical environment reading. Motion-Event supplies an On/Off event. Siren-Alert is the controlled output.

  2. Step 2

    Do
    Open Temp-Monitor Specifications. Read what environment input it uses. Identify the reported quantity. Compare it later with the gateway Home value.
    You will see
    The title says Temperature Monitor. Its description names temperature from Environment. It converts that input to a readable value. This is a numerical signal, not a motion trigger.
    Why it matters
    The simulated environment supplies the temperature. Its value may vary with the simulation clock. A number has different meaning from an event flag. The siren rules do not reference temperature.

  3. Step 3

    Do
    Open Motion-Event Specifications tab. Read how to stimulate the detector. Read its automatic deactivation period. Plan to inspect Home promptly after stimulation.
    You will see
    The title says Motion Detector. It detects motion from mouse movement. It deactivates after five seconds without movement. Direct Control says Alt-mouse move to interact.
    Why it matters
    This model supplies a short-lived event. The interaction is documented in Packet Tracer. The five-second interval explains the reset capture. It is not a measured physical detection range.

  4. Step 4

    Do
    On PC0 open Desktop and Web Browser. Visit http://192.168.25.1 and sign in admin/admin. Open Home device list and expand the three rows. Record the initial values before stimulation.
    You will see
    Temp-Monitor shows a numeric 4.0 °C in this capture. Motion-Event On is red Off. Siren-Alert On is red Off. All three named rows are visible together.
    Why it matters
    The baseline contains one value and two event states. The exact temperature can vary later. The siren is inactive before motion. A baseline is needed to interpret a change.

  5. Step 5

    Do
    Open the gateway Conditions page. Read both enabled motion rules. Check each condition and action target. Notice that neither rule names Temp-Monitor.
    You will see
    Motion starts siren tests Motion-Event On true. It sets Siren-Alert On true. No motion stops siren tests Motion-Event On false. It sets Siren-Alert On false.
    Why it matters
    The gateway maps a motion event to an alert. The second rule returns the alert to Off. Temperature is outside this rule path. These rows document the saved configuration.

  6. Step 6

    Do
    Close the PC window in the Logical workspace and hold Alt over Motion-Event. Move the pointer across the detector. Reopen or refresh Home immediately. Expand Motion-Event and Siren-Alert.
    You will see
    Motion-Event On is green On in this capture. Siren-Alert On is green On too. Temp-Monitor reads 9.0 °C at this moment. The siren changed with the motion event.
    Why it matters
    The simultaneous green states show the event path. The temperature is a separate changing input. Its numeric change is not evidence of causation. The rule uses motion, not temperature.

  7. Step 7

    Do
    Stop moving the pointer over Motion-Event. Wait more than five seconds. Refresh the Home device list and expand all three rows. Compare motion and siren with the prior capture.
    You will see
    Motion-Event On has returned to red Off. Siren-Alert On has returned to red Off. Temp-Monitor reads 2.9 °C in this capture. The numerical reading did not control the reset.
    Why it matters
    The detector self-clears after inactivity. The gateway Off rule then clears the siren. The changing temperature shows independent simulation time. The capture supports a simulated alert cycle only.

  8. Step 8

    Do
    Return to the Conditions list. Verify both rules remain enabled. Read the motion-only inputs once more. Save and reopen lab.pkt for another run.
    You will see
    Both rule rows still show Enabled Yes. The first maps motion true to siren true. The second maps motion false to siren false. No temperature threshold appears in either row.
    Why it matters
    The saved rules explain both observed alert states. A value and an event need different interpretations. Reopening verifies the learner project retains the setup. The exercise makes no hardware accuracy claim.

Chapter checks

These questions refer to the chapter’s examples. Use the return links to review their answers.

  1. What physically moves inside a MEMS capacitive accelerometer when the device accelerates?

    Return to the chapter’s knowledge check

  2. Why can a single MEMS accelerometer not distinguish a slow tilt from a genuine horizontal acceleration?

    Return to the chapter’s knowledge check

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