How to Build a Remote Controlled Robot

Be aware of what you will build. The first step in designing a remote-controlled robot is to recognize that you're not going to build a life-size, two-legged, humanoid robot that can do all your chores.Nor will you build a multi-limbed robot capable of reaching and picking up 100-pound weights.You need to start building a robot that can go forward, backward, left and right, controlled by you wirelessly.However, once you've laid the groundwork and built this simple robot, you can add and modify various details.Usually you should follow the principle that no robot is ever finished.It can always be improved.

Design your own robot. Before you build it, even before ordering the parts, you will have to design it.For your first robot you should choose a simple design, with just two servo motors on a piece of plastic.This project is really simple and usually leaves extra room to add extra features after completion.Think about building something about 15 x 20 cm.You will be able to draw it on the paper with a full-size ruler because it is quite small.But when you think about a larger, more complex robot, you should learn how to use CAD or a similar program, such as Google Sketchup.

Choose the pieces. It's not time to order the parts yet, but you should choose them now and know where to buy them.Try to order them from a small number of sites to save on shipping.You will need chassis materials, two "servo" motors, a battery, a transmitter, and a receiver.

• Choose a servo motor.To move the robot you will need to use motors.The first will give power to one wheel and the second to the other.This way you can implement the simplest method for steering:the differential transmission.This means that the robot will drive forward when both motors are spinning forward, will drive in reverse when both motors are spinning backward, and will spin when one motor is active and the other is stationary.A servo motor is different from a basic DC motor, because it is oriented, it can only turn 180° and it can go back to its position.This project will use servo motors because they make movement easier and you won't have to buy an expensive "governor" or a separate box of gears.Once you understand how to build a radio-controlled robot, you can make another one (or modify the first one) using DC motors, rather than servo motors.There are four basic features you need to worry about when purchasing servo motors:speed, torque, size/weight, and whether they are 360° changeable.Since the servo motors can only turn 180°, the robot would only be able to move forward a little.If the engine is 360° modifiable, you can make it spin continuously.Make sure the engine it really is 360° editable.Size and weight don't matter too much in this project, as you will likely have plenty of space.Try to make something medium sized.Torque is the force of motors.That's what gears are used for.If there are no gears and the torque is low, the robot probably won't be able to move forward, because it won't have the strength.Try to have high torque, but the higher it is, the lower the speed will generally be.For this robot, try to get a good balance between speed and torque.You can always purchase and mount a more powerful or faster servo motor after completing the build.Get the HiTec HS-311 servo motor for your first RC robot:It has a great balance between speed and torque, is inexpensive, and is a size that fits this robot.The HiTec HS-311 servo motor can be purchased here.
  • Since the servo motor can normally only turn 180 degrees, you have to modify it to have continuous rotation.Changing it you will cancel the guarantee, but it must be done.For detailed instructions on how to modify a servo motor go here.
• Choose a battery. You need to get something to power your robot.Do not attempt to use AC power:you don't have to plug it into the wall.You have to use DC power, i.e. batteries.
  • Choose the battery type.There are three types to choose from:alkaline, NiMH and NiCad, lithium polymer (LiPo).
    • Lipo batteries are the latest and extremely light.However, they are dangerous, expensive and require a special charger.Only use this type of battery if you already have robotics experience and are willing to spend more on the robot.
    • Nickel-cadmium batteries are the common rechargeable batteries.They are inserted into many robots.The biggest problem with these batteries is that if you charge them when they are not fully discharged, they will no longer hold a full charge.
    • NiMH batteries are very similar to NiCad batteries in size, weight and price, but overall perform better.These are generally the recommended batteries for a beginner's project.
    • Alkalines are the common non-rechargeable batteries.You will already have some because they are cheap and easy to find.However, they run out quickly and you have to buy them over and over again.Don't use them.
  • Choose battery specifications.You need to choose a voltage for your battery pack.The most common in robots are 4.8 V and 6.0 V.With these, most servo motors will move well.It is usually best to get 6.0V (which is fine for most servo motors) because it will allow your servo motor to go faster and have more power.Now you need to address the capacity of your robot's battery pack, which is in mAh (milliamp hours).The higher the capacity, the better, but it also becomes more expensive and usually heavier.For the size of the robot you are building, around 1800 mAh is recommended.If you have to choose between 1450 or 2000 mAh with the same voltage and weight, choose 2000 mAh.It may be a couple of euros more expensive, but it is still the best multipurpose battery you can get.Make sure you have a charger to recharge the battery pack.Here you can buy a 6.0V 2000mAh NiMH battery.
• Choose the material for your robot.You will need a chassis to connect all the electronic components.Most robots of this size are made of plastic or aluminum.For a beginner, it is recommended to use a type of plastic called HDPE.This plastic can be processed easily and is cheap.When deciding on the thickness, take it about 5 mm.As for the size of the sheet, you will probably need to get a fairly large one in case you make a mistake when cutting.It is usually recommended to take at least double the surface area needed for your robot.A piece of 5 x 600 x 600 mm HDPE can be purchased here.
• Choose a transmitter/receiver.This will be the most expensive part of your robot.It can also be considered the most important, because without it the robot cannot do anything.It is highly recommended that you purchase a good transmitter/receiver to start with, because it is the device that will limit the features of the robot.A cheap transmitter/receiver will move the robot fine, but you won't be able to add anything else.Additionally, the transmitter can be used for other robots you build in the future.So instead of buying a cheap one now and a more expensive one later, buy a better one now.It will save you money in the long run.However, there are different frequencies that can be used.The most common are 27 MHz, 72 and 75 MHz and 2.4 GHz.27 MHz can be used for airplanes or cars.It is commonly used in cheap remote-controlled games:it is not recommended except for small projects.72 MHz can be used Alone for aircraft.As it is normally used in large models, it is illegal to use in surface vehicles.If you employ this frequency, not only are you breaking the law, but it could interfere with an expensive airliner flying nearby.You risk causing a plane crash, with enormous repair costs or, even worse, you would endanger people's lives.The 75 MHz one, however, is done Alone for surface use:you could use it.However, the 2.4 GHz frequency is the best.It has less interference than any other frequency.It is advisable to spend a few dollars more to get a 2.4 GHz transmitter with receiver.After deciding which frequency to use, you need to decide how many "channels" you will use on the transmitter/receiver.The number of channels basically corresponds to how many functions you can control on your robot.For this robot you need at least two.One channel will allow your robot to go forward/backward and another will allow it to go left or right.However, it is recommended to have at least three.This is because, after you build the robot, you can always add another function.If you get four, you will usually have two joysticks.With four transmitter/receiver channels you can eventually add a claw.As mentioned before, you should buy the best transmitter/receiver your budget allows now, so you don't have to buy a better one later.You will also be able to use the transmitter and receiver again on other robots that you can build in the future.The Spektrum DX5e 5-Channel 2.4 GHz Radio System Mode 2 and the AR500 can be purchased together here.
• Choose the wheels.When choosing wheels, the three most important things you need to worry about are diameter, traction, and whether they will attach easily to your motors.Diameter is the length of the wheel from side to side, through the center point.The larger the diameter of the wheel, the faster it goes and the higher it can climb, but it will have less torque.If you have a smaller wheel, you may not be able to climb as easily or go very fast, but you will have more power.The quality of traction depends on the grip of the wheels on the surface.Make sure you have wheels with a rubber or foam ring, so they don't slip.Most wheels suitable for servo motors will be able to be screwed on correctly, so you don't have to worry.A type of wheel between 3 and 5 inches in diameter with a rubber ring around it is recommended.You will need two wheels.Precision disc wheels can be purchased here.

Now that you have selected your parts, you can proceed with your online order. Try to buy them from a small number of sites to try to save on shipping, especially if you buy everything at the same time.

Measure and cut the frame. Take a ruler and marker and measure the length and width of the frame on the material you plan to use for the frame.It is best to make it approximately 15 x 20 cm.Take the right measurements:the lines should not be crooked and make sure the length is right.Remember:measurements are taken twice, but you can only cut once!Here you are:now you can cut.If you use HDPE, you should be able to cut it the same way you would cut a piece of wood of the same size.

Assemble the robot. Now that you have all your materials and have cut the frame, all you need to do is assemble them all together.This can actually be the easiest step if you have designed the robot well.

• Mount the servo motors at the bottom of the plastic piece, towards the front.They should be placed sideways so that each “horn” of the shaft (the part of the servo motor that moves) faces a side face.Make sure there is enough space to fit the wheels.
• Attach the wheels to the servo, using the screws provided with it.
• Attach one piece of Velcro to the handset and the other to the battery pack.
• Place two pieces of Velcro on the robot - so that it has the other side - and attach the receiver and battery pack to them.
• You should now have a robot that features two wheels at the front and touches the floor at the back.There will not be a third wheel on this robot:it is precisely designed so that the back slides along the floor.

Connect the wires. Now that the robot is assembled, just connect everything to the receiver.Insert the battery into the socket on the receiver marked "Battery".Make sure you connect it correctly.Now, connect the servo motors into the first two channels on the receiver, where you see "Channel 1" and "Channel 2" written.

Charge the battery. Disconnect the battery from the receiver and connect it to the charger.Wait until the battery is charged.This could take up to 24 hours, so you will have to be patient.