You might have observed the following:

Question

(a) When you open your garage door, your next-door neighbor’s door might also open.
(b) Your neighbor complains sometimes that the TV channel is changing
automatically.
Can you think of ways to avoid such phenomena? Explain clearly.

Answer 1

(a) Garage door remotes controls use the typical frequency of around 400 MHz. A special digital coding system separates one system unit from another. Every garage door opener allows us to set the code in a series of small switches inside the garage. This code is a binary number, which is different from the neighbor’s code. However, if we accidentally set the code to that of our neighbor and if both the systems are operating at the same frequency, then both the doors start operating at the same time. To avoid this we should use different binary codes.

(b) In infrared remote controls which we generally use in TV and VCRs, we transmit the signal using pulses of infrared light. A special set of codes are used, depending upon the make and the model of the television which keep the various remotes from interfering with each other. Since infrared remotes use light, they cannot penetrate through walls. However they can make their way around corners. Thus, the TV channels of the neighbor might change sometimes. Different codes need to be used to avoid this.