Even though his main passion is not physics, he must have heard about Faraday’s cage. It is one of the most spectacular applications of physics in real life and you can really build one in your own backyard. If you want to learn how to build a Faraday cage, stay with us on the following pages and see how easy it is!
Before immersing yourself in the most surprising and interesting DIY project you have ever heard of, we should talk a little about the inventor: Michael Faraday. He was a British scientist who changed the fields of electromagnetism and electrochemistry. Actually, we have to thank him for the world in which we live and the future discoveries and technological inventions. His work in magnetic fields led to the invention of electromagnetic rotating devices that led to the electric motor and the use of electricity as the main source of energy for current technology.
Think about what our world would look like today, if we could not use electricity to power our devices. Many of the technological advances would not exist or could have another form and functionality.
In addition to establishing the basis for the electric motor, Faraday also discovered other surprising things, such as:
- how to use electromagnetic fields in physics;
- discovered that magnetism affects light rays;
- the principle of electromagnetic induction;
- The laws of electrolysis.
He was a man endowed with a huge thirst for knowledge and we have to thank him for that. There are only a handful of people in this world with such an impressive portfolio. He sits in the scientists’ heavy sand next to Einstein and Tesla.
Now that we’ve talked a bit about the inventor, let’s spend more time on the invention and see what a Faraday cage really is. If we try to decipher it by its name, we have a cage that was built by someone named Faraday, which is quite accurate. The cage can take many forms, but the principle is simple: it distributes an electric charge around its outside, without letting it in.
The outside of the cage acts as a conductor, allowing the electrical charge to flow while the interior is protected. The wonderful thing about Faraday’s discovery is that the inside of the cage is also protected by electromagnetic fields and microwaves.
As you can imagine, this amazing phenomenon has many applications in our daily life:
- For example, thanks to Faraday and his cage, we now know how to protect electrical appliances from lightning and electrical discharges by allowing additional energy to flow outward and keep sensitive interior mechanisms safe.
- Another useful application is aviation. The planes go through storms and sometimes (quite often in reality) are struck by lightning. If there were no protection to protect passengers and all those delicate systems, nobody would risk flying.
- The car we drive every day is a Faraday cage that protects us from lightning when we have to go through a storm.
- Microwave ovens are a kind of inverted Faraday cages, since they trap the energy of the microwave inside and use it to cook (or heat) the food.
- The shielded cables use the Faraday cage effect to keep the signals they carry pure. For example, the signal from your TV goes through a shielded cable to deliver a clear image on your device. If there is no shielding, the signal on the TV cable will mix with other signals that diffuse into the environment surrounding the cable.
- The vitally important telecommunications systems are kept safe from the electrical charges used by Faraday cages.
- Hospitals have their own Faraday rooms: MRI rooms where they must isolate any external electrical disturbance to get a clear picture.
- Important issues related to the state and business are discussed in the Faraday rooms, where no listening device works.
- All modern military weapons are based on communication, but this makes them extremely vulnerable to EMP (electromagnetic pulse) attacks (natural or artificial). A Faraday cage will protect everything inside an EMP.
Protection for your electronics from an EMP
An EMP or an electromagnetic pulse is a natural or artificial event that could send us all to the Stone Age in just a few seconds. These events can occur naturally (when we receive a flare from the Sun due to solar explosions) or caused by man (terrorist attack). An EMP is dangerous because it releases a large amount of gamma rays in the atmosphere. These gamma rays reach the Earth from the Sun every second, but our atmosphere manages to protect us from them.
If the amount of gamma rays suddenly increases, EMP occurs. The electromagnetic pulse will be dispersed in the air, with the speed of light, frying any electronic device in its path. The electrical lines, telephony towers, microwaves, hair dryers, radios, televisions, everything that works with electric power will be destroyed.
That is why the invention of Faraday is so important: the electronics will be protected in a cage from faraway days in the case of an electromagnetic pulse. Since they are easy to build and you do not need expensive materials, you should start thinking about how to protect your valuable electronic equipment. It may seem a little crisis of paranoia, since there were no such attacks but you never know. The people in Nagasaki had no idea how to react in the event of a nuclear attack and paid with their lives for this.
Just imagine the chaos that an EMP would create, especially now when we base our lives on technology. Electric cars would stop working (even when they are in motion), pacemakers would stop, endangering patients’ lives, communications would not be available, etc. If you have your electronic devices, you can safely communicate with government departments (the military also uses Faraday cages to protect their assets) and get valuable information on time.
Faraday cage from materials you have around.
You do not have to be a space scientist in physics to do a Faraday DIY project with your family or friends. You just need to understand some basic principles and apply them correctly. Now is the time to learn how to build a Faraday cage using materials you already have in our house.
There are some decisions you should make before starting your homemade Faraday cage:
- The shape. The cage can have any shape you want: spherical, triangular, oddly shaped, etc. If you decide to use the classic rectangular shape, it is equally fine, as long as you know that the shape does not affect the effectiveness of the cage.
- The conductive material. You must choose the material you want to place on the outside of the cage. This should be a simple decision since the material does not influence the activity of the cage (as long as it is able to conduct electricity). High-strength aluminum sheets are the cheapest materials for an efficient Faraday cage for DIY.
- Holes or without holes. A Faraday cage can have holes in its walls as long as they are not too large to allow the electromagnetic wave to enter. That is why you can use an aluminum mesh as the outer layer of the cage. You can also use metal containers such as metal trash bins or galvanized cans. Pay special attention to the door when using a mesh because there will be leaks. The door area needs additional insulation to operate the cage.
- Should I ground the cage? It is not a request but it is a strong recommendation. In case something goes wrong, the cage could electrify and electrocute anyone who touches it. If it is connected to ground, an additional layer of security is added.
- Moisture absorber to create a safe and moisture-free environment for the devices inside the cage. They will not help you if they survive an EMP, but they break due to excessive humidity. Desiccant packages of 50 g should be sufficient.
Now that you have everything you need, it’s time to start building:
- Begin by wrapping everything you want to put in the cage in a sturdy aluminum foil. You can add a garment before placing the sheet if the object you are wrapping around has sharp corners. This way you avoid any hole in the sheet. Make sure you put 3 layers of aluminum in each item; This is the ideal thickness.
- Take the container you are using as the walls of the Faraday cage and add a layer of protection inside. Here you can use a foam cushion or simply a cut cardboard box. The cushion will be a better protective layer, but if you’re not going to hit the cage against the walls, you should also be fine with the cardboard box. Be sure to add this inner layer on the walls, on the bottom and on the top. The items inside can not touch the walls of the container, especially if you are using a galvanized trash can.
- Add the moisture absorbent and the items you want to protect inside the container.
- Seal the lid and add an additional layer of aluminum tape on top. The tape layer is just to make sure that the seal is made and that there are no intrusions between the metal contacts. For the cage to work, this seal must be perfect.
Here you can see how it works:
Now, he has his own homemade Faraday cage ready to protect his electronic devices and EMP.
The final test – check if you did a good job
You can not produce an EMP to test the Faraday cage you just built, but there are other ways to see if it really works. Put inside your phone at a very high volume and an AM / FM radio while it is still being transmitted. Before fixing the lid in place, you can still hear the signal from the radio from inside the container. After everything is sealed, the radio should lose the signal and if you try to call your phone, it should not be available. If this happens, it means that you did a great job and that your Faraday cage is safe to use.
If you can still hear the radio and your phone rings while it is inside the sealed cage, look for holes in the container or in the foil used to wrap the items.
Tips and tricks
Now that we know how to protect our electronic devices, it’s time to learn some tricks on how to make the cage with materials at our disposal; for example, how to eliminate moisture without desiccants.
- Use nylon stockings filled with glass cat litter to absorb moisture from the inside. It is an economical and effective way to make sure that the inside of your cage is free of moisture;
- Pack your items and place them in the can in the order you will need them. If there are items that you need to check regularly, place them at the top;
- You could embed a solar panel in your Faraday cage to keep your electronic devices running even if the power lines are down. You could charge batteries and cell phones with the stored energy;
- In case you have not had the opportunity to make a Faraday cage and store everything you want inside, there is an emergency solution: your microwave oven. Microwave ovens are small Faraday cages upside down, which means they keep the energy inside to cook food. If the microwaves are turned off, your eyes will be slowed as you watch the food spin inside. If the EMP arrives and is not ready, place your small electronics in the microwave. It will act like a miniature Faraday cage and protect everything inside.
Electronics to put in the faraday cage.
First, you have to consider the size of the cage. You can not put a big-screen TV in a small trash can, right? After all, a big screen TV will not save your life and after EMP, there will be no television or Internet and it will be just a cold piece of furniture and a memory of what it used to be.
You must think of small electronic devices without which your life would be more difficult. Here are some examples:
- Hearing aid;
- A replacement pacemaker (if you or one of your family members uses one);
- Solar energy radio;
- Bidirectional communication station;
- Mobile phone;
- LED flashlight with batteries;
- Standard battery charger;
- Rechargeable and standard batteries;
- USB battery charger and solar batteries;
- Buy an external hard drive with enough space to put all the backup copies of your computer in it and place it in the cage;
- Cards with photos and copies of the documents you want to keep safe;
- A radiation detector that will be very useful to check the level of radiation after the EMP.
The list can continue according to the amount of space you have. You can always make more than one Faraday cage to store everything you need. Anyway, the idea is to store important equipment that can help you in a difficult situation. If you make more than one Faraday cage, you must label them so you know what’s inside without opening the cages.
Now you are ready for a very ugly scenario, in theory. Nobody could try one of these homemade Faraday cages against an electromagnetic pulse attack (artificial or natural). And the hope is that we can never do that. Still, it’s better to be prepared, just in case.
Do you really want to save your devices?
Well, in the end, the main conclusion is that the world as we know it is very fragile and can be destroyed in a matter of seconds. We do not even realize how much we depend on small electronic devices such as tablets, laptops, GPS system, radios and others. It is as if all of these were on Earth for thousands of years and nothing can make them disappear. Many people live in a kind of bubble, without worrying about what might happen and how they would react in a dangerous situation. It is time for us to leave our bubble and begin the preparations for different scenarios.
If there was an EMP attack tomorrow, half of the population would have no idea what to expect. Imagine how easy a world of terrorists can destroy our communications system, power lines and finances (we saw it in so many movies).
Each of these systems works with electrical power, which makes them extremely vulnerable to attack. We would be in the dark and when we realize what happened, the balance of power in the world has changed. It’s a very dark scenario and we hope it never happens, but the question remains: what would happen?
A homemade Faraday cage could be the last wall that stands between you and chaos. Why not build it, since it is a really simple and fun DIY project?