When was the last time you spotted lightning? Have you ever felt a jolt while getting out of your car, during winters? How do you think the lights go on immediately after you press the switch?
Note
Take a balloon, fill it up with air, and close the mouth of the balloon tightly. Now rub the balloon against your dry hair; do this for a few seconds, and take the balloon close to the wall. What happens when you do this? Write it down in your observation notebook.
From static electricity to electric current to the lightning in the sky, these are all examples of various effects of electricity.
Electricity is a physical phenomenon that occurs due to the presence and flow of the electric charge (the unit by which charge is measured is coulomb). Electricity causes many effects that we come across everyday.
All electronic devices-be it our phones, headphones, watches and clocks-all operate on the exact same power source, that is movement of electrons. We know now that the movement...
We now already understand the meaning of resistance, capacitance, voltage, and current. Every circuit needs some amount charge to flow in it to function. This need or requirement of current in the circuit is called current requirement. Whenever we apply a voltage to a circuit, the circuit uses/eats or draws current which is equal to voltage applied divided by the total resistance in the circuit. Or 1/R times the voltage applied where R is representative of resistance.
While building your circuit, sometimes you will realize that two different sensors in your circuit have two different types of current requirements; other times you have different voltage requirements. Think of this as the different tactics you use to avoid cleaning the room. In such conditions, we use resistors and capacitors in various combinations to get the desired results.
Do you remember how we compared the human body to robots in Chapter 1, The World around Us? Microcontrollers are like the brains in human beings. Similar to human brains, microcontrollers work on a simple input-output concept. So, what is this input-to-output concept?
Anything that is taken in or put in a system is called an input; similarly, output is what is given out of the system.
Look at the following diagram-it shows what a system looks like. This system could be a microcontroller or a human brain:
Microcontrollers receive the input information; they process that information and then produce an output. The human brain processes a lot of information too, even before birth. All day, every day, it processes information such as sounds, images, visuals, smells, touch, pain, expressions, and so on. What do you think is the input to the brain? The sense organs in humans provide this input to the brain.
You know, I always found automatic doors, escalators, and elevators very magical. Every time I would go close to a door and see it open on its own, I would always walk a little away from the door, to the left or to the right, to check at what point I will be close enough for the door to open. It has always been fun.
We interact and use multiple sensors on a daily basis even without knowing their presence. They are present everywhere! Don't you think they make our life simpler?
Note
Write about at least five different places that you know or think sensors are present. Also, guess the location in the product.
One very important thing that all of us should remember is that all the sensors work on the basic laws of physics. They use physical conditions such as light, temperature, pressure, humidity, and so on, using circuitry within them and converting them into electrical signals.
So, the insides of a sensor will look something like this:
Keep this block diagram in mind;...
There are so many sensors that we come across every day.
Here is a list of very widely used sensors:
Distance sensor (proximity sensor)
Temperature sensor
Humidity sensor
The very cool thing about sensors in the aforementioned list is that these sensors are used in many things around us, be it smart TVs, laptops, smart watches, home automation systems, or wearable devices. We will learn about these sensors now.
A distance sensor usually measures the distance between itself and an obstacle using the concept of light waves. A light wave originates from the sensor (from the transmitter of a sensor), bounces back from the obstacle, and is received by the receiver of the sensor. Think of this as you walking in an empty room and shouting something. The voice echoes. That is exactly how the light waves interact and bounce back too, they echo from the object.
In the case of a distance sensor, the first block is just a transmitter-receiver. The second block is what...
Before we start going deeper into this section, you need to know this: you are already an inventor, so you have the power to build all the sensors you want in the world! However, as Spidey's uncle Ben said, with great power comes great responsibility; as an inventor you always follow a process or an approach to solving problems. Remember the notebook you maintain, that's the one!
Write down the following three questions in your notebook:
Why?
What?
How?
Every time you see a problem, ask yourself these questions:
Why am I doing this?-Find out the answer to this by constantly observing and identifying the problem statements around you. Asking WHY helps you define the problem statement and gives you the reason to stick to the problem statement even when you are in self-doubt. For example, my observation is that the temperature in my city is increasing. Why is it increasing?-It is increasing because of pollution.
What are you going to do about the problem you found out by asking...
In this chapter, you learned about the building block of circuits. You now know about voltage, current, resistance, and the relationship between them. You learned about various combinations of resistors and capacitors and how they collectively work in circuits. You also learned about the physics behind sensors, you now know what process to follow to solve any problem in the world, and most importantly, you built your own sensor!
In the next chapter, you are going to learn everything about Arduino, how to write code, how to tinker with examples and attach sensors to Arduino. I am super excited. Are you?
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