TechKnowLab

 LDR/Photo-resister with Arduino: This articles aims to show the reader how to use an LDR, also known as a photo-resistor in their projects.  How to use an LDR with Arduino After reading this article, the reader will be able to connect and read a photo-resistor, and use the code in their future projects! Components Needed Arduino Breadboard Jumper Wires (Male to Male) Photoresistor 1x 220 Ohm resistor Wire all the components as per the circuit diagram given below. How do we measure resistance The LDR varies its resistance based on light hitting it, and the Arduino technically only reads voltages, so how do we measure resistance? We are not REALLY measuring the resistance in this circuit, instead we are creating a resistor divider network between the LDR and the resistor, which will vary the voltage directly based on the LDRs value. We then read the voltage out of the divider network and print that value. Code //Variables int inPin = A0 ; //Pin the sensor is connected to int sens

 PWM using Arduino: In this article we will look at Pulse-Width Modulation, how to use the Arduino to generate it, and what it does.  How to use the Arduino to generate Pulse-Width Modulation (PWM) You will understand what PWM is, and how to use the Arduino to generate it. We will do this by dimming an LED. An LED is a Light Emitting Diode, and it can only be connected one way. If you connect it in reverse, it will not work at all. You can distinguish the polarity of an LED in two ways. Firstly, there will be a longer leg and a shorter leg on the LED. The longer leg is positive and the shorter leg is negative. Sometimes however, the leg length may not be easily visible. For instance, if you have cut the legs shorter for a different project, or bent them for a breadboard. In this case, you can use the second method. The second method is to look at the plastic body of the LED. You will notice one side of it is FLAT. This signifies the NEGATIVE side of the LED. Components Required Arduin

  Introduction : Additive Manufacturing  Additive manufacturing uses data computer-aided-design (CAD) software or 3D object scanners to direct hardware to deposit material, layer upon layer, in precise geometric shapes. As its name implies, additive manufacturing adds material to create an object. By contrast, when you create an object by traditional means, it is often necessary to remove material through milling, machining, carving, shaping or other means.  Although the terms "3D printing" and "rapid prototyping" are casually used to discuss additive manufacturing, each process is actually a subset of additive manufacturing.   Additive Manufacturing Processes Binder Jetting   T his technique uses a 3d printing style head moving on x, y and z axes to deposit alternating layers of powdered material and a liquid binder as an adhesive. Directed Energy Deposition  Direct energy deposition additive manufacturing can be used with a wide variety of materials including c

 This article shows how to create serial connection through USB between your Arduino and your computer in order to monitor the status of a switch.  Components Required Arduino Board Bread Board Jumper Wires Momentary switch or Push Button 10k ohm resistor Computer with Arduino IDE Circuit and Connections 3 wires should be connected to the board. The first two, red and black, allow access to the 5 volt supply and ground by connecting to the two lengthy vertical rows on the side of the breadboard. Digital pin 2 and one of the push button's legs are connected by the third wire. Through a pull-down resistor (10k ohm in this case), the button's identical leg is connected to ground. The button's opposite leg is wired to the 5 volt supply.  When you press a pushbutton or switch, it connects two points in a circuit. The pin is linked to ground (through the pull-down resistor) and reads as LOW, or 0. When the pushbutton is open (not pressed), there is no connection between the two p