Servo is a special type of motor which converts electric signals in to shaft positions. Servos can be broadly classified as Industrial servos and Hobby grade [[wysiwyg_imageupload::]]servos.Industrial servos are generally heavy duty high power AC or DC servos widely used for precise robotic arms.Hobby grade servos are widely used in RC Hobbies like RC Plane, Cars Helicopters, Multirotors, Boats, hover craft, etc.They are mostly used to control the control surfaces (RC Planes) or for thrust vectoring mechanisms (hovercraft, boats, multirotors) or for steering mechanisms (RC Cars).Hobby grade servos are further classified as micro, standard, giant based on the torque they can provide, however their working principal is just the same.Based on speed of operation they are classified as Analog or Digital servos, Digital servos provide greater speed but consume more power.Speed of a servo motor is defined as time taken for shaft to move from 00 to 600 after the application of signal. In this article we will be using an ARDUINO clone board viz. FREEDUINO. 

In the last few years the interest in Unmanned Aerial Vehicles (UAVs) and their use for an ever increasing range of applications has grown tremendously. This [[wysiwyg_imageupload::]]type of aircrafts can be controlled remotely or programmed to fly in an autonomous way. They have been used for different types of applications as individual entities, both in military and civil tasks. Research related to this type of systems is being undertaken in many areas going from the design of more efficient aircraft aimed at specific applications, to the development of improved control electronics that provide for better autonomous behaviors, to optimized path planning strategies, or to opening new application domains. Currently, a whole new field of research is opening up in the area of coordinating UAV teams to cooperatively perform different missions. This field is still in its infancy and many exciting new approaches are being explored for different applications. Examples of these are works related to trajectory planning in UAV teams, real time target tracking, and many others. 

We all know Sun is the best source of energy source and has been shining since the universe was created. We can harness solar energy by either converting it into electricity using Solar cell or using solar thermal energy by means of solar cooker, solar water heater or by using it to heat or cool a room using solar passive systems. Amongst these the most popular and best method to harness solar energy is by using Solar cell. We all know during summer heat is more intense because sun rays are perpendicular to the earth surface and hence the solar energy is concentrated over a small region.This can be applied to solar cell as well viz. the power output from a solar cell is directly proportional to sine of angle between the cell surface and light rays. So it’s clear that the power output from a solar cell will be maximum when it is facing the sun i.e. the angle between its surface and sun rays is 900.Thus the setup by which the above objective is achieved is known as solar tracker. Solar trackers are continually being employed in practice to get max efficiency. In this project we will design a simplest single axis solar tracker and its concept can be expanded to make a full fledged dual axis solar tracker. We are making single axis for sake of simplicity and better understanding.  

Here is a very simple college project using Arduino and Accelerometer. Spirit Level (also called Level Bottle) is a tool which is used to see whether the surface is perfectly horizontal or not, this tool is used by plumbers and carpenters and some hobbyist to make perfectly level surfaceIn this project I present a Digital Version of this Spirit level.A typical analog one looks like this.