IoT wireless chips are low-power radio chips that let small devices, such as sensors, smart locks, bulbs and meters, connect to the home network or a hub while running for years on a small battery. IoT means the internet of things: everyday objects that contain a small computer and a network connection. Many of these chips combine the radio and a small processor on one piece of silicon.
The main problem they solve is power. A phone's Wi-Fi uses a lot of battery, but a phone is charged every day. A door sensor or a water leak sensor runs on one coin-sized battery, and should last for years without being touched. So these chips spend almost all their time asleep, using about one millionth of an ampere. They wake only when something happens, send a short message in a few thousandths of a second, and sleep again.
Different radios suit different jobs, and each follows one of the shared connectivity standards. Bluetooth Low Energy uses very little power over a short range, and a phone can connect to it directly. Zigbee and Thread let many small devices form a mesh network, in which they pass messages on for each other until the messages reach a hub. Low-power Wi-Fi chips let a device join the home router directly, with no hub, but they use more battery. For distances of several kilometres, LoRaWAN and other long-range radios carry small amounts of data on very little power.
Consider a door sensor on the main door of a flat in Chennai. It runs on a coin battery of about 220 milliampere-hours (mAh). The sensor sleeps until a magnet on the door moves away from it. When the door opens at 11:40 p.m., the chip wakes, sends a 20-byte message over Thread to the hub in about two milliseconds, and goes back to sleep. The hub passes the message to the home security app, which alerts the owner's phone. Each message uses so little energy that the battery lasts about three years.
Inside the device, the wireless chip works with a microcontroller (MCU), which runs the device's own logic, or the two are combined on one chip. These chips go into smart home appliances, smart bulbs and the sensors of home security systems. They also go into wearables such as the smart ring.
These chips differ from the Wi-Fi and Bluetooth chips in phones and laptops. Those chips aim for speed, for example to stream video, and the device is recharged every day. IoT chips aim for the longest battery life, and send only a few bytes at a time. Devices that must reach the mobile network instead use cellular IoT modules.