Smart home appliances are washing machines, fridges, ovens and other household machines that connect to the internet, so that the owner can control and watch them from a phone app. They are also called connected or Wi-Fi-enabled appliances. Many new washing machines and air conditioners sold in India now come with an app.
A smart appliance has three layers of software. The first is firmware on the machine's own chip, usually a microcontroller (MCU), which is a small computer on one chip. The firmware runs the motor, opens the water valve, reads the temperature and times every step of a wash. Some appliances run a real-time operating system (RTOS) under the firmware, so that each task happens exactly on time. The second layer is the app on the owner's phone. The third is the maker's cloud, which joins the machine to the app. The machine connects to the cloud over the home Wi-Fi, through an IoT wireless chip inside it. This three-layer design is explained in IoT architecture.
To set the machine up, the owner opens the app, and the app finds the new machine, often over Bluetooth. The owner types the home Wi-Fi password into the app. The app passes the password to the machine. The machine joins the Wi-Fi and registers itself with the maker's cloud, under the owner's account.
Take, for example, a front-loading washing machine in a flat in Thane. Midway through a cycle, it stops and shows an error code: the water is not draining. The firmware sends the code and the readings from its drain pump to the maker's cloud. The app tells the owner to clean the drain filter, and shows a short video of how to do it. The filter is already clean, so the owner books a repair from the app. The cloud already holds the error code and the pump readings. So the maker's field service management (FSM) system sends a technician who carries a new drain pump on the first visit. Without this data, a technician would often come once to find the fault, and again with the part.
The cloud also sends updates. The maker can fix a fault in the firmware, or add a new wash programme, and send the new firmware to every machine of that model over the internet. Such updates must carry the maker's digital signature, so that the machine accepts firmware only from its own maker.
A smart appliance is different from a plain machine with a timer. A timer can start a wash at 5 p.m. A connected machine can be started from anywhere, can report its own faults, and can be improved after it has been sold.