>So you like to sit on your sofa comfortable and operate your television without walking to the television to push some buttons. No wonder the first remote control was called **Lazy bone**.
@ikchris


<div class="pull-left"><center><img src="https://s6.postimg.cc/b9wuli79d/lazy_bone_remote_small.jpg"/><br/><em><a href="https://commons.m.wikimedia.org/wiki/File:SABA-corded-TV-remote.jpg">SABA corded Earlier remote control handset known as lazy bone: Wikimedia commons licensed under CCSA 3.0 unported</a></em></center></div>Remote control is an electronic device used to operate an electronic system from a distance, it works wireless today but works with wire in earlier technology as you can see in the image.  This control handset is designed to give electronic consumers convenience and maximum comfort.  With a remote handset, you can sit at your convenience and manipulate your electronic device_that is awesome right?

<h2>How Does Remote Control Work?</h2>

<div class="pull-right"><center><img src="https://s6.postimg.cc/6qfk2jiyp/ultrasonic.jpg"/><br/><em><a href="https://commons.wikimedia.org/wiki/File:Zenith_Space_Commander_600.jpg">Zenith Space commander<br> Ultrasonic remote control<br> handset: Wikimedia commons<br> licensed under CCSA 3.0 unported</a></em></center></div>

Have you ever wondered how remote control handset work? **I got the answer if you have ever asked**
Early remote control handsets work with ultrasonic tones. That is, Sound waves which is frequencies are higher than the maximum limit of the sound waves humans can hear.  The approximate maximum sound wave humans can hear is 20kHz but ultrasound waves have frequencies that range from 20kHz to several gigahertz(GHz)

In today's technology, remote control handset works with Infrared Radiation(IR). This is an electromagnetic wave which is wavelengths are longer than the wavelengths of visible light. The wavelengths of visible light varies from 390nanometers(nm) to 700nm while the wavelength of IR varies from 700nm to 1milimeter(mm).
<center>
https://s6.postimg.cc/6mqsjo70x/infrared_remote_control_handset.jpg [infrared remote controller handset: Wikimedia commons licensed under CCSA 3.0 unported](https://commons.wikimedia.org/wiki/File:Remote_control_for_tv.jpeg)
</center>

>Did you know Infrared Radiation was discovered by an astronomer of British Origin named Sir William Herschel in 1800?

In terms of frequency, the frequency of visible light varies from 430THz to 770THz while IR  has frequencies ranging from 300GHz to 430THz. This differences in frequencies and wavelength of Visible light and IR is the reason humans cannot see IR radiation
 <h4>Are You Confused About Visible Light  Simultaneously  having a lower range of wavelengths And Higher Range of Frequencies Than Infrared Radiation?</h4>
According to a wave formula shown below:
V=Fλ
 F=V/λ
where V is velocity(constant)
λ is wavelength
F is frequency
You can see that the frequency of a wave is inversely proportional to is wavelength. This implies that the higher the frequency of any wave, the lower the wavelength and vice versa.
**Hope I cleared your confusion?**
<h3>What emits the Infrared Radiation in a Remote control handset?</h3>
<div class="pull-left"><center><img src="https://s6.postimg.cc/m9i1xb80x/IR_LED.jpg"/><br/><em><a href="https://commons.m.wikimedia.org/wiki/File:IR_led.jpg">Infrared light emitting diode: Wikimedia commons licensed under CCSA 3.0 unported</a></em></center></div>Every remote control handset has IR LED(Infrared Radiation Light Emitting Diode) which is place at  top center. This IR LED can be covered with a Pyrex glass or left uncovered depending on manufacturers. 
Anytime a button is pushed on a remote control handset, the IR LED gives out some radiation. Based on this radiation, you can conduct a test for any remote. More emphasis on this later in this article.



<h4>What type of control system does Remote Handset Belong</h4>
A control system is established when different components, elements or devices are integrated to form a system than can manage, direct, command and regulate the behaviour of another system using control loops_so remote control handset  is a form of control system. It can be open loop or close loop depending on technology.
In some remote control handset, if the user inputs a command, lets say **volume increase of 10**, the volume of the system  being controlled will started to increase and will automatically stop increasing once it gets to 10. This kind is of closed loop control system 
In some other remote control handset, lets say *toy's car remote* once and operator pushes the forward button, the little toy would start moving forward and would never stop except the operator pushes the stop button. This type of remote control handset is of open loop control system. 
<center><img src="https://s6.postimg.cc/t35dpy281/IR_LED_remote_edit.jpg" /><br/><em>IR LED of a <br>remote control handset <br>Image Credit: @ikchris</em></center>

<h4>Why Should I Even Use Remote Control handset</h4>
1. Convenience: With remote control, you don not need to climb and operate your air condition system.
2. More Functions: Most LED televisions have only the power ON/OFF button, without their remote control handset, you cannot properly operation them
There are still other benefits.

<h4>My Remote Control Handset Stopped Functioning, How Do I Know if it is Faulty?</h4>
You can know if a remote control handset is faulty by conducting a simple test.
Recall, I have emphasized that the IR LED gives a radiation whenever a button is pushed on the remote handset. Whenever a button is pushed, a signal is created and amplified through an embedded transistor, this sends some voltage to the IR LED which gives out infrared radiation which is sensed by a sensor in the system being controlled.
<h5>Can humans even see Infrared Radiation?</h5>
Unfortunately, humans cannot see infrared radiation with their naked eyes, but can see it through some lens. And the good-news is that your smart phone's camera can see this radiation
Lets move on!!!
<h4>How Do I Conduct This Easy Test?</h4>
To conduct this remote control handset test, follow the steps below:
1. Launch the camera of your smart phone
2. Focus the camera on the IR LED located at the top center of your remote control handset
3. Push any button on the handset
4. Look at the screen of your phone
5. Observe if there is any glow as shown in the image below
<center><img src="https://s6.postimg.cc/pjjg07zj5/Remote_LED_radiating_day_edit.jpg" />
<em>Infrared Radiation from<br> a remote control handset. <br> Image Credit:</em> @ikchris</center>

The result gotten from the above test is what determines the fault, this fault now decides the solution. There are basically two faults with modern remote control handset and also two possible solutions. The two are:
1. **The IR LED Does Not Emit Radiation/Light**
**Solution**
a. Change the batteries and retest
b. Check if the spring connection the batteries has rusted, wet a piece of clothe with fuel and clean
c. Check if there is a partial contact between the printed circuit board(PCB) and the IR LED_if it exists, solder firmly(technical know-how required)
d. After the above steps, and still problematic, consider changing the IR LED entirely. You can get it from an old remote or a nearby electronic shop.
This would solve the problem.

2. **The IR LED Emits Radiation But Would Not Control your System/Device**
**Solution**
a. Change the batteries
b. Go to closer range with the device being controlled and push the button on the remote handset. 
If this did not solve the problem, then the sensor circuitry  in the device being controlled is faulty. Consult a technician to fix the issue if you are not a tech-savvy. Remember, **safety first**!!!
<center>https://s6.postimg.cc/jdr6kqf5t/remote_radiating_night_edit.jpg
<em>Remote control handset Infrared<br> radiation captured in the dark.</em><br> Credit: @ikchris</center>  

 <h3>Conclusion</h3>
The faults in a remote control handset are minor faults since the input voltage is 3VDC. So with this basic understanding of infrared radiation and lens of your camera, you can debug any fault in a remote control handset and even correct it with the solutions given in this lecture. You can save some Dollars and stress of taking your electronic system to a technician_yes, you can an it is as simple as that.

***Task***: Take any remote control handset around you and perform all the test described in this lecture, comment your result.

Thanks for your time!!! Am always around, we can relate anytime via @Steemstem [discord](https://discord.gg/KJK4vNf)
Keep steeming!!!
I remain your bretheren @ikchris

<h2>REFERENCES</h2>
Consider reading the below topics for more understanding
* [Remote Control](https://en.wikipedia.org/wiki/Remote_control)
* [Control System|Open loop and closed loop](https://www.electrical4u.com/control-system-closed-loop-open-loop-control-system/)
* [Infrared Radiation](https://en.wikipedia.org/wiki/Infrared)
* [How Remote Control works](https://electronics.howstuffworks.com/remote-control2.htm)
* [Remote Background](https://www.zenith.com/remote-background/)

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