How to Build a Remote Control Robot: 14 Steps

Many people consider a robot as an autonomous machine. However if you read the definition of "robot", remote control devices can be considered as such. You may think that assembling a robot is difficult, but it is actually easy if you know how to do it. This article will explain how to build a remote controlled robot.

Steps

Step 1. Determine what you should build

You won't be able to build a full-scale humanoid robot with two legs and do all your chores. You won't even be able to build a robot with many claws that can lift 100 lbs. (50 kg). You need to start with a robot that can go right, left, front and back, controlling it wirelessly. Once you start with the basics, you can add and modify things to your machine. In general, you should adopt the principle that a robot is never complete, since it can be modified and improved over time.

Step 2. Create the schematic for your robot

Before building your robot, even before ordering the parts, you need to design it. Create a simple design for your first robot, which is made up of 2 servo motors on a plastic platform. This design is very simple and generally leaves room for extra accessories. Design an approximate dimension of 15cm x 20cm. In the case of this simple robot, you must draw it on paper with the help of a ruler. Draw on the paper the same size that the real robot should be, as it will not be very big. If your robot is larger or more complex, learn to use CAD or a similar program to design it.

Step 3. Choose the parts

You haven't ordered them yet. You can choose the parts and where to buy them. Try to find all of them in one store so you can ask for a discount. Try to order the parts from as few websites as possible and sometimes you can save money on shipping. You will need the material for the chassis, two servo motors, a battery, a motorized transmission, a transmitter and a receiver.

• Choose a servomotor. To move the robot, you will need motors. The first motor will be used to move one wheel and the second for the other. In this way, you can steer the robot using the simplest driving method. This means that if you move it to the front, the 2 motors will turn in the same direction and vice versa, if you move it to the right, the right wheel locks and vice versa. A servomotor is different from a direct current one because it has gears, it does not rotate more than 180 degrees and it sends information about its position. This project will use servo motors because they are easier and you do not need to purchase separate "speed controllers" or transmissions. After you understand how to build a remote controlled robot, you will want to make another one (or modify an existing one) using DC motors instead of servo motors. There are 4 basic considerations that you need to take into account when choosing servo motors: speed, torque, size or weight and if it is flexible at 360 degrees. Since servo motors normally rotate 180 degrees, your robot will only be able to move a little. If the motor is flexible to 360, you can modify it to rotate continuously. Make sure it is modifiable. The size and weight may not matter, as there is a place to put it. Pick something average in size. Torque is the force of the engine and is the reason the transmission is used. If there is no transmission and the torque is low, maybe the robot will not move because the motor has no power. You should have a lot of torque, although normally the higher the torque, the lower the speed. For your robot, find a suitable balance between torque and speed. You can buy and install better engines once you are done. It is recommended to buy the HiTec HS-311 servos in your first remote controlled robot. This model has a very good balance between torque and speed and they are cheap, you can order them here.

  Since the servo only rotates 180 degrees, you will need to modify it to rotate continuously. Modifying a servo will void the warranty, but you must

• Choose a battery, as you need to power the robot. Do not try to use alternating current (eg by plugging it into the wall). Use a direct current source (i.e. batteries).
  • Choose a type of batteries. There are 3 types of batteries to choose from. Lithium, NiMH, NiCad and alkaline ones.
    • Lithium batteries are the most modern you can get and are extremely light, but dangerous, expensive and require a special charger. Use them if you have experience handling them and the extra money to invest in your robot.
    • NiCad (Nickel Cadmium) batteries are the most common rechargeable batteries. They are used in many robots. Their biggest problem is that if you recharge them when they're not empty, they don't last as long as a full charge.
    • NiMH (Nickel Metal Hybrid) batteries are very similar to NiCads in price, size and weight but perform better and are generally recommended for beginners.
    • Alkaline batteries are the most common and are not rechargeable. They are common (you probably have some), cheap and easy to get. However, they sell out quickly and you will have to buy them over and over again. Avoid them.
  • Consider the battery specifications. Look at the voltage of the batteries. The most common for robots are 4.8V and 6.0V. Most servos operate on either of these, although the 6-volt battery is generally recommended (if the servo motor can support it, which is normally the case). because it will allow the engine to go faster and have more energy. Now you need to take care of the capacity of your robot's battery pack. Battery capacity is measured in MaH. The higher the parameter, the more expensive and perhaps heavy the battery will be. The recommended battery for the robot size is 1800 mAh. If you must choose between a 1450 mAH battery or a 2000 mAH battery of the same voltage and weight, go for the latter. It is a little more expensive, but it is also a better one. Don't forget to buy the charger too. You can buy a NiMH battery pack from 2000mAh at 6.0V: here.
• Choose the material for your robot. You need a chassis where to hold the electronics. Most robots are made of plastic or aluminum. For beginners, it is recommended that it be a type of plastic called HDPE. It is cheap and easy to manipulate. Choose a 1/4 inch (6mm) thickness. Choose a slightly larger dimension (twice the planned size) in case you spoil a cut. However, you may want to purchase a 1/4 x 24 x 24 inch (60cm X 60cm X 6cm) sheet of HDPE here.
• Choose the transmitter / receiver. In your robot, this will be the most expensive part but also the most important since without it, the robot will not do anything. It is recommended to buy a good quality one because it will limit everything you can put inside. A cheap transmitter / receiver will move your robot at a suitable speed, but you won't be able to add anything else to it. Also, you can use for other robots you want to build in the future. So instead of buying a cheap one now and then a more expensive one, just buy the best there is. It will save you money in the long run. There are several commercial frequencies you can use and the most common are: 27 MHz, 49 MHz, 72 MHz, 75 MHz, and 2.4 GHz. The 27 MHz ones are used in cheap toys like remote-controlled commercial cars and planes. The 27 MHz is only recommended for small projects. The 72 MHz is only used in airplanes and its application in vehicles is prohibited. If you use this frequency in a vehicle, you not only violate the prohibition, but you can interfere with an expensive remote control plane that could crash and you will have to pay for it or even worse, you could hit a person and injure or even kill them. The 75 MHz is only used for surface level; that is, on pavement, so you could use this one. However, the 2.4Ghz is the best. It has less interference than any other. Once you have chosen the frequency, you must decide how many "channels" you want. The channels are chosen according to how many things you want to control in your robot. For a simple robot, at least 2 are required. One channel controls the drive servo motor and the other the steering. However we recommend that you have a remote control system with 3 or 4 channels. This is because after building the robot, you may want to add more to it. If you have 4 channels, you will generally have two controls. With a 4 channel transmitter / receiver, you could add a claw. As said before, you should pick the best transmitter / receiver you can afford so you don't have to buy a better one later. You can use the transmitter and even the receiver again on another robot that you could build. You can buy the RC Spectrum DX5e 5-Channel and 2, 4Ghz Mode 2 system and the AR500: here.
• Choose the wheels. Keep 3 things in mind when choosing wheels: diameter, drive, and coupler. The diameter is the length of the wheel from side to side, through center point to the other side. The more diameter these are, the faster they will go and the more they can climb. The smaller the diameter, they may not be able to scale very easily or they may go fast but they will have more energy. Traction is how well the wheels stick to the surface. Make sure you get wheels with a rubber or foam rim, to prevent them from slipping. Most wheels that are made to mate with servos will use screws to assemble themselves, so you don't need to worry too much about that. Wheels between 7.5 and 12.5 cm (3 and 5 inches) in diameter with rubber tires are recommended. You will need at least two. You can buy the precision disc wheels can here.

Step 4. Order the parts

Now that you have your choice, order them. Try to order from as few sites as possible to save money on shipping.

Step 5. Measure and cut the chassis

Get a ruler and a marker, and measure the length and width of the chassis on the material you will use to make it. We recommend that you draw an area of 15 cm X 20 cm. Measure again and make sure the lines are not twisted and are the length you want. Remember, measure twice and cut once. If you use HDPE, you can do it in the same way as if you were cutting a piece of wood.

Step 6. Assemble the Robot

Now, with your chassis cut out and materials ready, you need to assemble the pieces. This will be easy if your design has no errors.

1. Mount the servos in front of the plastic base, near the front. They should be on opposite sides to the axle (the part of the servo that moves pointing sideways. Make sure you leave room to mount the wheels.
2. Use the servo screws to mount the wheels.
3. Attach a piece of velcro to the base of the receiver and another to the battery.
4. Attach two opposing pieces of velcro to the base of the robot, one for the receiver and one for the battery.
5. Now you have a robot with 2 wheels in front and a slope in the back. There will be no "third wheel" as it will slide only sideways.

   

   Step 7. Connect the cables

   Now that you have assembled the robot, you need to connect everything to the receiver. Hook everything up the right way where it says "battery" on the receiver. Make sure you connect it in the correct way. Now plug the servos into the first two channels of the receiver, where it says "channel 1" and "channel 2".

   

   Step 8. Charge the bacteria

   Unplug it from the RC system and plug it into the charger. Be patient and wait for the bacteria to have a full charge, it may take 24 hours.

   

   Step 9. Play with your robot

   You already have everything, press the transmitter, put obstacles in the way, play with the cat, etc … Now is when you can think about making it grow, add something to it!

   Advice

   • You can put your old Smartphone on the robot and use it as a video transmitter in case it has a camera. You can use it in conjunction with Google Hangouts as a video chat link between the robot and your computer or other device to direct your robot from an outside room.
   • If you press right and the robot goes left, switch the servo connections on the receiver channels. For example, if you have channel 1 to the right servo, pass this to channel 2 and vice versa.
   • Add more stuff. If you have an extra channel on your transmitter / receiver, you can add another servo motor to do something else. If you have an additional channel, you can make a claw that can be closed. If you have two additional channels, try making a claw that opens and closes, and moves from left to right. Use your imagination.
   • You may require an adapter to connect the battery to the charger.
   • You could use a 12V bike battery for high torque and speed.
   • Verify that the transmitter and receiver are of the same frequency. Verify that the receiver has the same or more channels as the transmitter, so all the transmitter channels will be used.

   Warnings

   • Do not use the 72 MHz frequency unless you are building a plane. It is illegal in surface vehicles and you could injure or even kill someone.
   • Beginners should not use an AC source (that is, plug it into an electrical outlet) for any home project. An alternating current source is extremely dangerous.
   • Using a 12V battery can cause the motor to explode if the motor does not have the same voltage capacity.
   • Using a 12V battery in a 110 to 240 VAC motor will cause smoke to come out and breakdown quickly.