How Does the Remote Controller Work? 

It got dark earlier in winter. Daniel had been staying in his room since he came back home. Mom heard the noises made by collision between tables and chairs. She was curious to have a look and found he was squatting at the bedside and swinging the clothes pole under the bed. She asked, "What are you looking for? I hear the noises far away."

Daniel stood up and said, "Our teacher organizes us to send New Year gifts for the children in the mountain areas. I want to give them the remote-control racing car received from Uncle a few days ago. But I've found the remote controller for a long time. I cannot figure out why it stays under the bed."

After hearing this, Mom bent down and found a black cuboid lying under the bed. She took the pole from him and moved toward it. She lay on the ground and took it out with efforts. When it was taken out, he dusted her trousers happily.

"You can't leave stuff lying around anymore," Mom reminded him.

“OK. Let me try this." He took out the car and attempted to control it with remote controller. However, the car didn’t move after he pressed the button for several times. He looked at his mother for help. Mom took the remote controller and the car, looked over them for a while and said, "This remote controller is not the one for the car. It is a wrong one. You should find out the right one."

He pointed to a mess in the room helplessly and said, "I just turned the room upside down and can't find it. I only saw this one under the bed."

Mom had no choice but to comfort him to think of other gifts.

It may be the only option. However, he felt a little confused, and asked, "Why can't this remote controller control the car?"

While helping him put away the scatted toys in the room, Mom replied, "The remote controller transmits signals through radio waves. Generally speaking, the remote controllers are paired with what they can control. Different remote controllers have radio waves with different frequency, just like they speak different languages. Only the one that is paired with the remote controller can understand that language."

He was even more curious after hearing that: how did we let the car be under the control of the remote controller?

Mon continued to explain, "The working principle of the remote controller is actually very simple. First, a 'telephone line' should be placed between the remote controller and the machine to be controlled to form a connection. This 'telephone line' is mostly invisible, such as radio waves for cars and infrared rays for TV sets."

He asked, "What are infrared rays?"

Mom thought for a while and said, "Infrared rays and radio waves are electromagnetic waves. Our world is full of electromagnetic waves. You can imagine that we live on a 'cobweb' we can't see every day. Each 'spider silk' on the 'spider web' is an electromagnetic wave of one frequency. The remote controller and what they control are connected by a 'spider silk'."

“Program is also needed for the remote controller to control. The program is a language that the machine can understand. The action that a car can do and the instructions of the remote controller will be written on its chip. Therefore, the remote controller can instruct the car to make corresponding action. Then we can let machines follow our instructions by pressing the button on the remote controller."

He seemed to understand a bit, and said, "Is the remote controller like a translator, who will translate our words into what the machine can understand?"

“You are right," Mom nodded with praise.

"Have you decided what present do you want to give?" After cleaning up the toys, she stood up and asked.

Daniel rubbed his head. He had not made his decision yet. 

Author: Huang Jing