How to Make a Robot: Part 1

Robots

When I was young, Robots were one of the things which used to mesmerize and compel me to think about them. I used to dream about them, talking and playing with them, giving orders to do my home work. I always wanted to make my own Robot so that I can make him do whatever I used to saw in dreams. That time I was not aware that to make a single robot, hundreds of hardware components are programmed by thousands of codes in which millions of instructions are hidden. To make a robot we require hardware components, robotic software and programming knowledge about them.     

  •  Batteries
  •  Actuators
  • Motors & servos
  • Sensors
  • Microcontrollers
  • Structure material

Batteries: For making our robot work, we need a power supply. As a source of power we use batteries. A battery is one or more electrochemical cells which convert stored chemical energy into electrical energy. There are two types of batteries: Primary batteries, these are disposable batteries designed to be used once. Another type is secondary batteries which are rechargeable batteries; they can be used number of times. We can find batteries in different sizes as well.  We can get as much power as we want for our robot. This is done by placing batteries in parallel. Placing batteries in parallel will give us certain amount of current we need. But we must be very careful while we do this because wiring batteries in parallel can cause inefficiency and sometimes damage. We can use Lithium-ion batteries, most advanced form to get portable power plus we can recharge Li-ion batteries whenever we want to. However Nickel-cadmium batteries are perfect for small sized robots, we can get highest power from these types of batteries, another advice while connecting batteries in parallel is never connect an old battery with a new one as their rate of charging and discharging is always different.

Battery

Actuators: An Actuator is a kind of motor for moving and controlling a system. It needs a source of energy to operate. It can be in the form of electric current, pneumatic and hydraulic fluid pressure. It is based on the principle of converting any form of energy into motion, what they do; they transform an input signal into motion given to them. Actuators create motion insider robots. In language of robotics, actuators are the muscles of robots. Most popular actuators are electrical motors. Linear actuators are used in industrial robots to provide them forward and backward motion.

Actuator

 

Motors and Servos: We generally use brushed and brush less DC motors in Robot. However, AC motors are also in use but they are popular for industrial robots. Electrical motors convert electrical energy into mechanical energy. DC motors are very commonly used in small sized robots. It is nothing but an electric motor which runs on direct current electricity. DC-motors are very easy to use. Servos are also used with motors. A servo is actually an automatic device that is used to correct the performance of the system Servos are used in robotics for different uses: e.g. to move a sensor around, or to move the legs of a robot. A servo can be modified to use as a DC motor. The Good thing with DC motor is that it is non-polarized so we can reverse the direction of voltage. Voltage is an important parameter to consider as torque depends on voltage, the more voltage we provide, the more torque it will produce. But we have to do it wisely as less voltage will lead to very less torque whereas large amount of voltage can cause overheating which may lead to damages.  If you apply too much, it will overheat and the coils will melt.

Sensors: A Sensor is a kind of a device which is used to transfer physical phenomena into electrical signals. We used sensors to take internal feedback and external interaction with the environment as well. A sensor must have accuracy, Preciseness and must satisfy operating range. There are a wide variety of sensors we use: Metal detectors, UV detectors, Gyro, resistive bend sensors, IR sensors are used when we design a simple moving Robot or a robot which is made to detect obstacles, Sensors are mainly used for detecting purposes like motion detection, obstacle detection even we have sensors for color detection as well.

color sensor

Micro-controllers: Micro-controllers are nothing but small computers on a single IC which have  programmable I/O peripherals, memory and Processor cores. In our day to day life the things we use microcontrollers are found in almost every small machine or device we use. From washing machine to microwave oven these small smart computers can be found in each and every automatic machine nowadays. They are very commonly used as they are economical, small in size and require almost zero power plus can be found in large varieties. Thus, very commonly used in making different types of robots.

Micro-controller


In short, a micro-controller is nothing but a black chip with pins. This black chip when contains some additional components like capacitors timers etc. we called it as an augmented micro-controller or simply micro controller. In augmented micro-controller we don't have to do assembling as they already have inbuilt features. The most important part of any micro-controller is its I/O ports. The input port is used to take input data from the sensor and then according to this data output signals are sent by output ports to external parts like motor or servo. The I/O port is of two types: Analog Input Ports and digital I/O ports.

Analog input ports are used to connect sensors to our robot. It is also known as analog to digital convert. They convert analog signal into digital signal sensors. Sensors take data in which is in analog form. Actually we record voltage which is in number.


Digital I/O Ports: Digital ports are just like analog ports; they are rarely used in sensors. They are used in on/off switches. They are used to control motor speed plus they are used in LED. This is done by sending 5v for on and 0v to show off. There is an interesting fact which I have faced when I have designed one of robots. I wanted my Led to glow as half of its brightness as it normally does, now let me tell you how it can be done... Use a  SQUARE WAVE, except this you can also make your motor speed half of its original speed by using the same wave. Actually square waves are like turning something on and off so fast that it is like as if you are sending an analog signal to do the same function.

PWM wave

Electronics: Electronics contribute a lot (no doubt) in the designing of robots. Materials like Capacitors, Resistors, LEDs, Voltage-regulators, rectifiers, crystal oscillators, transformer and transistors Potentiometers, diodes relays etc. are used in its designing.

Structure materials: As in constructing any building where cement and concrete materials are required, we also require some materials to give our robot a structural form. Base is the first thing in its structure. we can use wood. We can try Balsa wood. It is very light in weight. Carbon fiber can also be another good option as it is also very light in weight and proves strong. But its strength to weight ratio is high. HDPE. A light weight plastic can also be used as it is economical compared to aluminum. We also need tape, glue and epoxies in its designing. Now all you need is to use appropriate algorithm suitable according to your type of robot and design a new robot by using these hardware components.

Conclusion

Designing a robot is not a big deal. but we should have a very clear idea about what we want to design and complete knowledge about the materials we have to use to design our dream robot. Any type of confusion regarding any hardware material should not be avoided as little knowledge about anything can be dangerous. It's better to collect all the information about the component (involving all its benefits and harm it can cause) you want to use in building your robot. One more thing which is really very important the activities should be safe and should not create any harm to you as well as surroundings. Hope it would be helpful. SO GOOD LUCK!!!!