Sending Data to Two Serial Devices at the Same Time

You want to send data to a serial device such as a serial LCD, but you are already using the built-in serial port to communicate with your computer. On a Mega this is not a problem, as it has four hardware serial ports; just create two serial objects and use one for the LCD and one for the computer: void setup() { // initialize two serial ports on a Mega Serial.begin(9600); // primary serial port Serial1.begin(9600); // Mega can also use Serial1...

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Receiving Serial Data in Arduino

You want to receive data on Arduino from a computer or another serial device; for example, to have Arduino react to commands or data sent from your computer. It’s easy to receive 8-bit values (chars and bytes), because the Serialfunctions use 8-bit values. This sketch receives a digit (single characters 0 through 9) and blinks the LED on pin 13 at a rate proportional to the received digit value: /* * SerialReceive sketch * Blink the LED at a rate proportional to the received digit value */ const int ledPin = 13; // pin the LED is connected...

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Drakness Detector using 741 opamp IC

The circuit below is darkness detector that is it automatically turns on the LED when LDR senses no light. LDR is the light dependent resistor when exposed to darkness, a LDR has a tremendous amount of resistance. Depending on the specific LDR in use, its resistance can be anywhere from over 100KΩ to well over 2MΩ. When exposed to bright light, a LDR's resistance drops drastically. Again, based on the LDR, it may be to 5KΩ or below or to about...

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what are Infrared LEDs ?

Infrared LEDs are just like ordinary LEDs but the light output cannot be seen. To view an infrared LEDs, turn it on with the appropriate battery and dropper resistor and view it with a camera. You will see the illumination on the screen. Infrared LEDs are sometimes clear and sometimes black. They operate just like a red LED with the same characteristic voltage-drop of about 1.7v. Sometimes an infrared LED is pulsed with a high current for a very...

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Laser Ray Effect using 555

This circuit produces a weird "Laser Ray" sound and flashes a  LED at approx 5Hz.  COMPONENTS USED: 1.one 555 IC 2.one 100nF Ceramic Capacitor 3.one 10uF Electrolytic Capacitor 4.one 220K resistance 5.one 470ohm resistance 6.one LED 7.one 8ohm Speaker 8.one 6-12v supply ...

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Delayed Start Circuit using 555 IC

This circuit does not turn on for XX seconds after power is applied. Adjustable from 1 second to 2 minutes.The delay can be adjusted by changing the resistance between pin 6 and ground. Either you can use a 1M Variable Resistor or use different resistances to get different delays in turning on the circuit. Just Connect a LED to pin 3 of 555 along with a resistor to delay the start of LED. Resistances Between pin 6 and Ground and their Respective...

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Toggle LED on off using 555

This circuit will toggle the output each time the switch is pressed. The action cannot be repeated until the 10u charges or discharges via the 100k. In this Project we will connect an LED to the pin 3 of 555,when the button will be pressed the LED will toggle on off. COMPONENTS REQUIRED : 1.one 100k Resistor 2.two 10k Resistor 3.one 555 IC 4.one 10uF Electrolytic capacitor 5.one push button 6.one 470ohm/220ohm resistor 7.one LED 8.one...

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LED Fading/Blinking using 555 IC

This circuit makes a LED fade on and off.  first charges a 100u and the transistor amplifies the current entering the 100u and delivers 100 times this value to the LED via the collector-emitter pins. The circuit needs 9v for operation since pin 2 of the 555 detects 2/3Vcc before changing the state of the output so we only have a maximum of 5.5v via a 470R/220R resistor to illuminate the LED.   COMPONENTS REQUIRED: 1. one 470ohm...

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Programmable LED MATRIX [ARDUINO]

This led matrix can be programmed using arduino, various patterns can be made using functions and by specifying the LED's on the array. components- transistors- BC547 Resistances- 470 ohm and 1K ohm Arduino Uno hookup wires breadboard Circuit Schematic- Sketch- int x [4] = {13,12,11,4}; //Pins of x axis in numerical order int y [4] = {10,7,8,2}; //Pins of y axis in numerical order void setup () {  for (int a=0; a<4;...

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ARDUINO: Driving DC Motors using Transistors and PWM

DC motors, which you can find in numerous devices around your home, rotate continuously when a DC voltage is applied across them. Such motors are commonly found as the driving motors in radio control (RC) cars, and as the motors that make the discs spin in your DVD player. DC motors are great because they come in a huge array of sizes and are generally very cheap. By adjusting the voltage you apply to them, you can change their rotation speed....

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Transistor Tester using 555 IC

The 555 operates at 2Hz. Output pin 3 drives the circuit with a positive then zero voltage. The other end of the circuit is connected to a voltage divider with the mid-point at approx 4.5v. This allows the red and green LEDs to alternately flash when no transistor is connected to the tester. If a good transistor is connected, it will produce a short across the LED pair when the voltage is in one direction and only one LED will flash. If the transistor...

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Integrated Circuit chips

Figure below shows what is often referred to as an integrated circuit (IC). The circuit is actually etched onto a tiny wafer or “chip” of silicon, embedded in a black plastic body, which is properly referred to as the “package.” Tiny wires inside the package link the circuit with the two rows of pins on either side.                                       ...

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Sound , Electricity & Sound

Time to establish a clear idea of how sound is transformed into electricity and back into sound again. Suppose someone bangs a gong with a stick. The flat metal face of the gong vibrates in and out, creating sound waves. A sound wave is a peak of higher air pressure, followed by a trough of lower air pressure. The wavelength of the sound is the distance (usually ranging from meters to millimeters) between one peak of pressure and the next peak. The...

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origin of LoudSpeakers

Loudspeakers utilize the fact that if you run a varying electrical current through a coil situated in a magnetic field, the coil will move in response to the current. This idea was introduced in 1874 by Ernst Siemens, a prolific German inventor. (He also built the world’s first electrically powered elevator in 1880.) Today, Siemens AG is one of the largest electronics companies in the world. When Alexander Graham Bell patented the telephone in...

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XBEE Cheatsheet

    Source: www.tunnelsup.c...

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Atmega AT328P pin mapping

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Arduino:Reading Digital Inputs with Pulldown Resistors

All digital inputs use a pullup or pulldown resistor to set the “default state” of the input pin. Imagine the circuit in Figure below without the 10kΩ resistor. In this scenario, the pin would obviously read a high value when the button is pressed.But, what happens when the button is not being pressed? In that scenario, the input pin you would be reading is essentially connected to nothing—the input pin is said to be “floating.” And because the...

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Arduino: Pulse-Width Modulation with analogWrite()

we can generate analog output values by using a trick called pulse-width modulation(PWM). Select pins on each Arduino can use the analogWrite()command to generate PWM signals that can emulate a pure analog signal when used with certain peripherals. These pins are marked with a ~ on the board.On the Arduino Uno, Pins 3, 5, 6, 9, 10, and 11 are PWM pins. If you’re using an Uno, you can continue to use the circuit from Figure 2-1 to test out the analogWrite()command...

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