Which among the following is not true about IoT?

The Internet of Things (IoT) is a network of physical devices — embedded with microcontrollers as their processing core — that use sensors to sense the environment and actuators to act on it, communicating over wireless technologies (Wi-Fi, Bluetooth, Zigbee, cellular) without needing constant human involvement. IoT is engineered for connectivity and automation, not for guaranteed security: constrained processors, diverse protocols, and often weak default credentials make IoT one of the more security-vulnerable categories of computing, as shown by real-world incidents such as the Mirai botnet.

Checking each statement against this definition: using microcontrollers, using sensors and actuators, and using wireless technology are all standard, true characteristics of IoT architecture. Claiming IoT is fully safe, however, contradicts how IoT actually behaves in practice.

Independent check: industry references such as the OWASP IoT Top 10 list weak authentication, unpatched firmware, and insecure network services as recurring IoT vulnerabilities — confirming that IoT cannot be called fully safe.

• IoT uses Micro Controllers — true; matches the standard IoT architecture.

• IoT uses Sensors and Actuators — true; matches the standard IoT architecture.

• IoT uses wireless technology — true; matches the standard IoT architecture.

• IoT is fully safe — false; IoT security is a well-documented weakness, not a guarantee.

Since the question asks for the statement that is NOT true, the statement "IoT is fully safe" is the one that does not hold, because IoT security remains one of its most cited limitations.