Computer peripherals are the devices that connect to a computer from outside: keyboards, mice, webcams, headsets, speakers and separate touchpads. They plug in by a USB cable or connect without wires. Each one has a small chip inside, usually a microcontroller, that runs firmware, the software built into a device that controls it.
What does that chip do? In a keyboard, the keys sit over a grid of switches. The microcontroller checks the whole grid about a thousand times a second, finds which switch is closed, and sends the code for that key to the computer. In a mouse, a tiny camera takes thousands of pictures of the desk surface every second. The mouse's chip compares each picture with the last one to work out how far, and in which direction, the mouse has moved. In a webcam, an image sensor captures the picture, and a processing chip adjusts the brightness, focus and colour before sending the video on. In a headset, a chip strengthens the voice and removes background noise.
Wireless peripherals connect in one of two ways. Some use a small USB receiver that plugs into the laptop. Others use Bluetooth, the short-range radio that also connects earbuds. Both use very little power, so a wireless mouse can run for months on one battery. A separate touchpad uses a touch controller chip to sense where a finger is.
Most peripherals come with companion software that the user installs on the laptop. It lets the user change what each button does, adjust the webcam, and install firmware updates. A company can use the maker's management software to apply the same settings and updates to every device it owns. Headsets and webcams made for offices are also tested with the main video conferencing apps, so that, for instance, the mute button on the headset also mutes the call.
Imagine a customer support centre in Mohali with 400 support staff on two shifts. Each of them wears a USB headset for eight hours of calls. The headset has two microphones: one near the mouth and one facing outward. Its chip compares the two signals and removes sounds that reach both equally, such as the conversation at the next desk. So the customer hears the support executive, not the room. Six months after the purchase, some customers complain of an echo on calls. The headset maker finds the cause and releases a firmware update. The IT team uses the maker's management software to install it on all 400 headsets overnight, through the computers they are plugged into. The echo complaints stop.
The peripherals market depends on how people work. When many employees started working from home, sales of webcams and headsets rose sharply. Peripheral makers design much of their firmware and companion software in India, including in Chennai.