Ultrasonic Radar For A Home PC System Essays - Electric Motors

Ultrasonic Radar for a Home PC System One of the fastest changing and most expensive fields, is that of technology. Our computers, printers, modems, and much more is being outdated faster than anything else in the world. Just as we buy a new computer that does what we want, the industry comes out with a new option on a smaller and better computer. There seems to be so much changing that unless we invest our life savings into technology, we are considered obsolete like our computers. What used to fill an entire room, is so small now that it can be swallowed with a glass of milk. A computer used to be a mechanical engine that had many moving parts and was very slow. Now computers design computers that are tenfold their own power and a tenth the size, with less parts and using less power. An airport or an army base used to have huge structures that could send out signals to find out if any aircraft were approaching. This technology is now offered to people who have a computer with microsoft's quick basic, or a Macintosh, and space (equivalent to that of a coffee-pot) to spare. Ultrasonic radar is now a small component for your computer, giving computer operators a chance to see low flying objects, household furniture, and even themselves on their PC screen. Just to impress a neighbour or friend is reason enough to build your own ultrasonic radar station. Similar to that of a Polaroid, ultrasonic transducers are used in this type of radar. A rangefinder emits a brief pulse of high frequency sound that produces an echo when it hits an object. This echo returns to the emitter where the time delay is measured and thus the result is displayed. The Polaroid rangefinder is composed of two different parts. The transducer (Fig. 1) acts as a microphone and a speaker. It emits an ultrasonic pulse then waits for the echo to return. The ranging board is the second part (Fig. 2). This board provides the high voltages required for the transducer, sensitive amplifiers, and control logic. Since R1 is variable it controls the sensitivity of the echo detector. A stepper motor rotates the transducer to get a 360o field of view. For entire assembly see Figure 3. An Experimenter is hooked up to the ranging board to control the ranging board and to measure the round trip time of pulses. It also controls the stepper motor and communicates with the control computer. The connections between the Experimenter, ranging board, and transducer are shown in Figure 4. The ranging board's power requirements are usually under a 100 mA, but at peak transmission the circuit can draw up to 2 Amps of current. Power passes from GND (pin 1) and V+ (pin 9). To avoid malfunction a 300mF or greater should be connected between pin 1 and pin 9 (or alternately pin 16 and pin 5). Another 300mF resistor should be added to the Experimenter end of the cable. Figure 5 shows the timing diagram of the ranging boards's signals. It takes about 360 microseconds to transmit the pulses. The transmitter waits 1 millisecond for the pulse transmission and transducer to complete it's task. Then the experimenter waits for the pulse echo to return. If a pulse is detected the board sets ECHO at high. The Experimenter times the difference between BINH going high to ECHO going high. The experimenter sets INIT to low, waits 0.5 seconds for the echo, if no echo is heard the experimenter cancels the measurement. The measured time is sent to the computer which then calculates, at thousands of calculations per second, the distance based on the speed of sound (1100 feet per second). With a program called DISTANCE.BAS the exact speed of sound can be calculated according to the local weather conditions. The stepper motor is used to rotate the radar so it can scan 360o around the room. An ordinary DC motor would not do for such a project. The rotation must coincide with the emissions and the receptions of the echoes. In a DC motor the armature rotates and the brushes connect successive commuter bars to windings to provide the torque. The speed of this motor depends heavily on how much load there is and how much voltage is applied. A stepper motor has different wires to each winding. By energizing a winding the armature rotates slightly, usually a few degrees. By sequentially charging one winding after another the armature can rotate completely around. By

James Madison, 4th President of the United States

James Madison, 4th President of the United States James Madison (March 16, 1751–June 28, 1836) served as Americas 4th president, navigating the country through the War of 1812. Madison was known as the Father of the Constitution, for his role in its creation, and a man who served during a key time in the development of America.   Fast Facts: James Madison Known For: Americas 4th president and the Father of the ConstitutionBorn: March 16, 1751 in King George County, VirginiaParents:  James Madison, Sr. and Eleanor Rose Conway (Nelly), m. September 15, 1749Died: June 28, 1836 in Montpelier, VirginiaEducation: Robertsons School, College of New Jersey (which would later become Prrinceton University)Spouse: Dolley Payne Todd (m. September 15, 1794)Children: One stepson, John Payne Todd Early Life James Madison was born on March 16, 1751, the eldest child of James Madison, Sr., a plantation owner, and Eleanor Rose Conway (known as Nelly), the daughter of a wealthy planter. He was born at his mothers stepfathers plantation on the Rappahannock River in King George County, Virginia, but the family soon moved to James Madison Sr.s plantation in Virginia. Montpelier, as the plantation would be named in 1780, would be Madison Jr.s home for most of his life. Madison had six brothers and sisters: Francis (b. 1753), Ambrose (b. 1755), Nelly (b. 1760), William (b. 1762), Sarah (b. 1764), Elizabeth (b. 1768); the plantation also held more than 100 enslaved persons. The earliest education of James Madison, Jr. was at home, probably by his mother and grandmother, and at a school located on his fathers plantation. In 1758, he began attending the Robertson School, run by Scottish tutor Donald Robertson, where he studied English, Latin, Greek, French, and Italian, as well as history, arithmetic, algebra, geometry, and geography. Between 1767 and 1769, Madison studied under the rector Thomas Martin, who was hired by the Madison family for that purpose. Education Madison attended the College of New Jersey (which would become Princeton University in 1896) from 1769–1771. He was an excellent student and studied a range of subjects, including oratory, logic, Latin, geography, and philosophy. Perhaps more importantly, he made close friendships at New Jersey, included the American poet Philip Freneau, writer Hugh Henry Brackenridge, lawyer and politician Gunning Bedford Jr., and William Bradford, who would become the second attorney general under George Washington. But Madison grew ill in college, and stayed in Princeton after he graduated until April 1772, when he returned home. He was sickly most of his life, and modern scholars believe he likely suffered from epilepsy. Early Career Madison didnt have a vocation when he left school, but he soon became interested in politics, an interest perhaps stirred but at least fed by his continuing correspondence with William Bradford. The political situation in the country must have been exhilarating: his zeal for freedom from Britain was very strong. His first political appointment was as a delegate to the Virginia Convention (1776), and then he served in the Virginia House of Delegates three times (1776–1777, 1784–1786, 1799–1800). While in the Virginia house, he worked with George Mason to write Virginias constitution; he also met and established a lifelong friendship with Thomas Jefferson. Madison served on the Council of State in Virginia (1778–1779) and then became a member of the Continental Congress (1780–1783). Father of the Constitution Madison first called for a Constitutional Convention in 1786, and when it was convened in 1787 he wrote most of the U.S. Constitution, which outlined a strong federal government. Once the Convention ended, he, John Jay, and Alexander Hamilton together wrote the Federalist Papers, a collection of essays that were intended to sway public opinion to ratifying the new Constitution. Madison served as a U.S. Representative from 1789–1797. On September 15, 1794, Madison married  Dolley Payne Todd,  a widow and socialite who set the pattern for the behavior of White House first ladies for centuries to come. She was a well-liked hostess throughout Jeffersons and Madisons time in office, holding convivial parties with both sides of the Congress in attendance. She and Madison had no children, although John Payne Todd (1792–1852), Dolleys son from her first marriage, was raised by the couple; her son William had died in the 1793 yellow fever epidemic that killed her husband. In response to the Alien and Sedition Acts, in 1798 Madison drafted the Virginia Resolutions, a work that was hailed by anti-federalists. He was secretary of state under President Thomas Jefferson from 1801–1809. Embargo Act and the Presidency By 1807, Madison and Jefferson became alarmed at increasing reports on upheavals in Europe suggesting that Britain would soon go to war with Napoleons France. The two powers declared war and demanded that other nations needed to commit to a side. Since neither the Congress nor the administration were ready for all-out war, Jefferson called for an immediate embargo on all American shipping. That, said Madison, would protect American vessels from almost certain seizure, and deprive European nations of a needed trade that might force them to allow the U.S. to remain neutral. Passed on December 22, 1807, the Embargo Act would soon prove unpopular, an unpopularity that eventually led to U.S. involvement in the War of 1812. In the 1808 election, Jefferson supported Madisons nomination to run, and George Clinton was chosen to be his vice president. He ran against Charles Pinckney, who had opposed Jefferson in 1804. Pinckneys campaign centered around Madisons role with the Embargo Act; nevertheless, Madison won 122 of the 175 electoral votes. Negotiating Neutrality Early in 1808, Congress replaced the Embargo Act with the Non-Intercourse Act, which allowed the U.S. to trade with all nations except France and Great Britain because of the attacks on American shipping by those two nations. Madison offered to trade with either nation if it would stop harassing American ships. However, neither agreed. In 1810, Macons Bill No. 2 was passed, repealing the Non-Intercourse Act and replacing that with a promise that whichever nation would stop harassing American ships would be favored and the U.S. would stop trading with the other nation. France agreed to this and the British continued to stop American ships and impress sailors. By 1811, Madison easily won the renomination for the Democratic-Republicans, despite being opposed by DeWitt Clinton. The campaigns main issue was the War of 1812, and Clinton attempted to appeal to both those for and against the war. Madison won with 128 out of 146 votes. War of 1812: Mr. Madisons War When Madison started his second administration, the British were still forcibly attacking American ships, seizing their cargo, and impressing their sailors. Madison asked Congress to declare war: but support for it was far from unanimous. The war, sometimes called the Second War for Independence (because it resulted in the end of U.S. economic dependence on Britain), pitted a barely prepared U.S. against the well-trained force that was Great Britain. On June 18, 1812, Madison signed a declaration of war against Great Britain, after Congress, for the first time in American history, voted to declare war against another nation. Americas first battle was a disaster called the Surrender of Detroit: The British, led by Major General Isaac Brock, and Native American allies, led by the Shawnee leader Tecumseh, attacked the port city of Detroit on August 15–16, 1812. U.S. Brigadier General William Hull surrendered the town and fort, despite having a larger army. America fared better on the seas, and eventually retook Detroit. The British marched on Washington in 1814, and on August 23 they attacked and burned the White House. Dolley Madison famously stayed in the White House until she ensured that many national treasures were saved. The New England Federalists met at the Hartford Convention in late 1814 to discuss pulling out of the war, and there was even talk of secession at the convention. But, on December 24, 1814, the U.S. and Great Britain agreed to the Treaty of Ghent, which ended the fighting but resolved none of the pre-war issues. Retirement After his presidential term in office ended, Madison retired to his plantation in Virginia. However, he still stayed involved in political discourse. He represented his county at the Virginia Constitutional Convention (1829). He also spoke against nullification, the idea that states could rule federal laws unconstitutional. His Virginia Resolutions were often cited as a precedent for this but he believed in the strength of the union above all. He took a leadership role in the formation of the University of Virginia, especially after Thomas Jeffersons death in 1826. Madison was also a slave owner- Montpelier had 118 slaves at one point- who helped found the notorious American Colonization Society to help resettle freed blacks in what would become Liberia, Africa. Death Although Madison remained vigorous and active during his early retirement, beginning after his 80th birthday in 1829, he began to suffer from longer and longer spells of fever and rheumatism. Eventually he was confined to Montpelier, although he continued working when he could through the winter of 1835–1836. On June 27, 1836, he spent several hours writing a thank you note to George Tucker, who had dedicated his biography of Thomas Jefferson to him. He died the next day. Legacy James Madison was in power at an important time. Even though America did not end the War of 1812 as the ultimate victor, it did end with a stronger and independent economy. As the author of the Constitution, Madisons decisions made during his time as president were based on his interpretation of the document, and he was well-respected for that. In the end, Madison attempted to follow the Constitution and tried not to overstep the boundaries set before him as he interpreted them. Sources Broadwater, Jeff. James Madison: A Son of Virginia and a Founder of the Nation. Chapel Hill: University of North Carolina Press, 2012.Cheney, Lynne. James Madison: A Life Reconsidered. New York: Penguin Books, 2014.Feldman, Noah. The Three Lives of James Madison: Genius, Partisan, President. New York: Random House, 2017.Gutzman, Kevin R. C. James Madison and the Making of America. New York, St. Martins Press, 2012.Ketcham, Ralph. James Madison: A Biography. University of Virginia, 1990.