The whole system has designed and configured such a way that when an intruder disturbing ATM, there is a high degree of certainty that the alarm system will deliver audio Signal. These devices are mounted on backroom of ATM and are used primarily to detect an attack on the ATM. The technology relies on an unstable mechanical
configuration that forms part of the electrical circuit. When vibration occurs, the unstable portion of the circuit moves and breaks the current flow, which produces an alarm. The technology of the devices varies and can be sensitive to different levels of vibration.