How Do RC Cars Work?


How Do RC Cars Work

RC cars may be considered tiny toys by many. But, despite their modest size, they pack a lot of technology under their hoods. One of the most common questions is what exactly happens behind the scenes that makes them move.

How do RC cars work? RC Cars work using radio signals. The radio signal is sent from the controller to the receiver in the RC Car. Once the RC Car receives the signal, it is decoded and translated into specific movement or action. For an RC Car to work, it needs to be powered by batteries or fuel.

And this is the gist of it. However, there is a lot more happening every time you press a button or pull a trigger. If you want to find out more, read on.

What Do RC cars Need in Order to Work?

For an RC Car to work, it needs to have several basic components. Let’s break down how each one of these works.

Transmitter

The transmitter is the controller that you hold with your hands. Usually, this handheld gadget is very similar to your TV remote control. Depending on what buttons you press, the transmitter creates and sends a specific signal that tells the vehicle what to do.

For the transmitter to work, it needs to be powered; typically, this is achieved with either a 9-volt battery or double-A batteries.

Receiver

It all starts with the signal sent from the transmitter, but you need a device that can intercept that signal and translate it into actual mechanical action. And this looks like the perfect job for a receiver. Basically this is an antenna. It intercepts and decodes the radio signal.

Motor(s) or Engine

All of these signals will be worth nothing if you do not have something to make your RC vehicle move.

The motor is responsible for your vehicle accelerating, going backward, or slowing down. There can be multiple motors installed on your RC vehicles. One motor can be designated to turn the front wheels left or right.

And a second motor can be used to power the rear wheels to go forward or backward. Some of the cheaper (and older) RC vehicles can even have four small motors, each powering one wheel.

Power Source

Just like we need petrol for our regular vehicles, we need a power source for our RC vehicles too. The majority of RC vehicles work with batteries. The batteries provide the needed power for the electrical motor to work and translate that energy into movement.

The receiver and all other electrical components in your RC car need electrical charge as well, which is supplied by the battery. Certain RC vehicles have petrol or nitro engines; they are powered by fuel instead of batteries.

Circuit Board

A circuit board is also needed to make the RC car work properly. The circuit board is the logical system that translates the different signals and electrical charges between the various components of the RC car.

Servo

The servo is a vital part of your RC vehicle. The servo converts the electrical signal into a movement. Usually, it is used to operate the steering system of the car. Servos are a reliable and cheap way to make your RC car move in the desired direction.

Speed Controller

The speed controller regulates the RPM and the speed of the RC vehicle. The battery-powered RC cars have an electric speed controller (ESC), and the fuel-powered RC cars usually have a throttle servo.

 

How Does the Radio System of an RC Car Work?

With the basic components covered, now, let us explore the radio system of the RC Cars.

The radio system is usually comprised of the transmitter and the receiver.

Every time you turn the wheel on the transmitter, pull or push the throttle trigger, or any of the controllers and buttons, a unique signal is created and sent to the receiver.  When the specific signal reaches the receiver, it tells the specific parts of the RC vehicle what to do.

For example, the receiver can tell the speed controller to accelerate or slow down, or the steering servo to make the vehicle turn left or right.

How Do the Transmitter and Receiver Communicate With Each Other

The cheaper RC cars work with signals in the 27 Mhz and the 49 Mhz frequency range. This means that if you have two 27 MHz RC vehicles close to each other, there can be some interference happening.

You can even control the two cars at the same time that way. To control two RC cars separately, you need to make sure they are operating on different frequencies.

Certain RC vehicles have a label stating that they can be operated near up to several other RC vehicles at once. These models usually have a channels switch (that is frequently color-coded). This changes the frequency slightly while still staying in the same range.

For example, you can use one car at 27.095 MHz (Orange) and Another one at 27.145 MHz (Yellow). They are both in the 27 MHz range but will not interfere with one another. Some of the other frequently used channels are:

  • 26.995 (Brown)
  • 27.045 (Red)
  • 27.195 (Green)
  • 27.255 (Blue)

Today some of the newer and higher-quality RC vehicles work in the 2.4 GHz frequency range. The 2.4 GHz range allows your controller to connect and listen only to your RC vehicle. And each controller has its own unique signature, so there is no interference. The higher frequency also allows the RC vehicles to work at longer distances (30 to 80 meters).

 

How Are the Transmitter and the Receiver Connected

The standard 27 and 49 MHz transmitters and receivers both take special plug-in crystals that are set to communicate and work at the same frequency.

But if there are ten people with RC vehicles nearby (working in the 2.4 GHz range), how does the receiver know which signal to listen to? The receiver and the transmitter have to be bound first for the RC vehicle to work properly. (Something very similar to how certain remote control garage doors work) Some RC vehicles come already bound, so you may not have to do that with every RC car.

 

How Does the Radio Signal Translate Into a Mechanical Action?

Every time you press a button, trigger, or a switch, an electrical signal is created and sent to the RC car. When you press a specific button, this causes a specific circuit found on the circuit board to be completed (a lot similar to how electrical circuits in our homes work).

When the circuit is completed, it sends electrical pulses. These electrical pulses are comprised of a set of synchronization pulses, followed by the actual pulse sequence.

The synchronization pulses inform the receiver that there is incoming information then the actual pulse sequence tells the receiver what the information is.

For example, the number of pulses will mean different actions like:

  • 16 pulses – Go forward;
  • 28 pulses – Go forward while turning left;
  • 34 pulses – Go forward while turning right;
  • 40 pulses – Go backward;
  • 46 pulses – Go backward while turning right; and
  • 52 pulses – Go backward while turning left.

So when you pull the throttle trigger, the receiver will send a signal that contains 16 pulses. These pulses will have the receiver send positive current through the circuit board to the motor powering it up and making the RC car go forward.

All of these pulses operate in one particular MHz range. Any other signals with different MHz are filtered out.

 

How the Different Channels Work

Each function of the RC Car works on separate channels. These channels should not be confused with radio channels or radio frequencies. Rather this refers to how the separate electric components are connected.

To work properly, RC vehicles need to have at least two channels. The channels are designated and associated with the control of different aspects of the vehicles.

The first channel always controls the steering. And the second channel is dedicated to speed control. If the vehicle has other accessories and features like LED lights, wench, reverse movement, and more, each one of these may need a separate channel.

 

How Does an Electric RC Car Work?

Electric RC Cars use an electric motor that is powered by electricity. Usually, this is done through the use of a battery pack.

The most widely used type of electric motor used for RC toys is the brushed electric motor. However, recently the brushless electric motors are becoming increasingly more popular.

Brushed vs Brushless RC Motor

 

How Does a Nitro RC Car Work?

The nitro RC cars have an engine that works with fuel. The fuel is usually methanol-based mixed with oil and nitromethane (and hence why they are called Nitros).

The percentages of each ingredient can vary a lot. The nitromethane can be anywhere between 0% to 60%, and the oil can be 8% up to 25%. However, the usual ranges of nitro and oil are about 10% to 40% and 15% to 20%, respectively.

 

How Does a Petrol RC Car Work?

These are the big boys in the neighborhood. Typically petrol RC cars are a lot bigger compared to the rest of the bunch.

What separates them, though, is that they work with a two-stroke engine. This is the same engine that you will find on a weed-wacker or a chainsaw.

Two-stroke engines work with mixed fuel. Mixed fuel is a mixture of petrol and two-stroke oil.

 

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