IoT ATM Security Monitor using Vibration Sensor

ATMs hold cash in public, often unguarded spaces, and physical attacks — drilling, cutting, gas explosions, ram-raiding — keep evolving faster than branch security budgets. Guards and CCTV record what happened; they rarely stop it happening. A low-cost sensor layer that reacts the instant the machine body is attacked changes the equation: a vibration event can trigger a local deterrent and a remote alert within seconds, while the evidence is still fresh. The engineering is deliberately simple and robust — a vibration switch with an adjustable threshold, a door-tamper input, an ESP32 to judge and report, and a buzzer plus strobe for the local response. This project builds the complete monitor: the SW-420 sensing chain with a buyer-run sensitivity tuning procedure, confirmed-event logic that rejects single knocks, Telegram and MQTT alerting, a dashboard with a timestamped severity-graded event log, and arm/disarm plus service mode for maintenance.

1. The SW-420 vibration switch and the reed-switch door sensor are sampled continuously by the ESP32.
2. A vibration trigger starts a confirmation window: only repeated triggers inside the window escalate to a confirmed attack event; isolated knocks are logged as minor.
3. On confirmation the ESP32 fires the buzzer and strobe LED immediately and queues the remote alert.
4. The event — type, severity, timestamp, sensor channel — is published over MQTT and sent through the Telegram bot to the owner.
5. The dashboard appends the event to the severity-graded log and updates the machine status card.
6. Arm/disarm commands from the dashboard change the monitoring state; service mode suspends vibration alarms while keeping door events active.
7. The buyer tunes the SW-420 sensitivity potentiometer for their demo setup using the included knock-test procedure, so the threshold matches the mounting.

Tech stack:

• ESP32 DevKit (Arduino-core firmware)
• SW-420 vibration sensor module with sensitivity adjustment
• Reed switch for door-tamper sensing
• Buzzer and strobe LED for local deterrent
• Telegram bot plus MQTT broker for alerting
• Web dashboard (status card, event log, arm/disarm controls)
• 5 V adapter with battery backup for the node

• [Vibration event detection] An SW-420 module with a sensitivity potentiometer watches the machine body; confirmed-event logic requires repeated triggers inside a time window before an alarm fires, rejecting single knocks.
• [Door-tamper input] A reed switch on the service door reports opening events as a second, independent alarm channel alongside vibration.
• [Local deterrent] A loud buzzer and strobe LED fire on a confirmed event to startle the attacker and draw attention, driven directly by the ESP32.
• [Instant remote alerts] Telegram bot messages and MQTT publishes carry the event type, severity and timestamp to the owner within seconds of confirmation.
• [Event-log dashboard] A severity-graded, timestamped log of every vibration event, door event, arm/disarm action and alert delivery, with daily summaries.
• [Arm/disarm + service mode] Keypad/PIN-style arming from the dashboard; service mode suspends vibration alarms during maintenance without disabling door monitoring.
• [Offline local alarm] The buzzer, strobe and event buffering run entirely on the ESP32 — a Wi-Fi outage stops remote alerts, never the local response.

• Complete ESP32 firmware (sensor sampling, confirmed-event logic, Telegram/MQTT alerting, arm/disarm, service mode, offline buffering)
• Wiring diagram and sensor-mounting guide
• SW-420 sensitivity tuning guide (knock-test procedure the buyer runs on their demo rig)
• Alerting setup guide (Telegram bot creation, MQTT broker)
• Web dashboard app (status card, event log, controls, daily summaries)
• Project report PDF (background, sensor choice, event-logic design, evaluation method)
• PPT presentation for final review
• Viva Q&A preparation document (vibration sensing, threshold logic, MQTT, Telegram bots, IoT security basics)
• Setup guide (Wi-Fi provisioning, first arm/disarm test)

• The SW-420 is a digital threshold switch, not a calibrated accelerometer: it reports that vibration crossed a set threshold, not a force in newtons, and the report states this plainly.
• Sensitivity must be tuned for the mounting — nearby construction, roadworks or a slammed shutter can trigger false alarms, and the tuning guide documents the tradeoff openly.
• Remote alerts need internet; if Wi-Fi drops, only the local buzzer/strobe and buffered log keep working until the link returns.
• This is a deterrent and alerting prototype for academic demonstration, not a certified bank-grade security system — no claim of stopping a determined physical attack is made.
• The demo mounts on a model ATM enclosure; real ATM integration would need bank-approved, tamper-evident mounting hardware beyond this project's scope.
• Battery backup covers short outages; extended power cuts need a larger UPS-style supply (documented as the extension path).