Build a motion-sensing alarm with a PIR sensor and an Arduino microcontroller.
In this simple project, we’ll build a motion-sensing alarm using a PIR (passive infrared) sensor and an Arduino microcontroller. This is a great way to learn the basics of using digital input (from the sensor) and output (in this case, to a noisy buzzer) on your Arduino.
This alarm is handy for booby traps and practical jokes, and it’s just what you’ll need to detect a zombie invasion! Plus, it’s all built on a breadboard, so no soldering required!
Step #1: Gather your parts.
- This project requires just a few parts, and because you’re using a solderless breadboard and pre-cut jumper wires, you won’t need any tools at all — except your computer and USB cable to connect the Arduino.
Step #2: Wire the Arduino to the breadboard.
I bet some of you had the same problem. I was working on this circuit on breadboard and I found out I do not have means to power that circuit. Batteries are too expensive for testing one circuit. In the end I was able to build small power supply that solved my problems.
Many times we can build PSU with small amount of elements. That is the story in this case. I upgraded PSU that already have 12 V output to 9 V with help of linear voltage regulator.
Be careful and cautious while proceeding with any project.
Step 1: Parts and materials.
– low voltage connector
– 2 pins connector
– cooling element with nut and bolt and with isolating foil (foil is optional)
– piece of black and red wire and two pins
– 7809 voltage regulator
– 470 uF capacitor and 100 nF capacitor
– PSU with output between 12 and 16 V Continue reading
Whether it’s an electronic novice or an expert professional, a power supply unit is required by everybody in the field. It is the basic source of power that may be required for various electronic procedures, right from powering intricate electronic circuits to the robust electromechanical devices like motors, relays etc.
A power supply unit is a must for every electrical and electronic work bench and it’s available in a variety of shapes and sizes in the market and also in the form of schematics to us.
These may be built using discrete components like transistors, resistors etc. or incorporating a single chip for the active functions. No matter what the type may be, a power supply unit should incorporate the following features to become a universal and reliable with its nature:
- It should be fully and continuously variable with its voltage and current outputs.
- Variable current feature can be taken as an optional feature because it’s not an absolute requirement with a power supply, unless the usage is in the range of critical evaluations.
- The voltage produced should be perfectly regulated.
Every project needs a power supply. As 3.3volt logic replaces 5volt systems, we’re reaching for the LM317 adjustable voltage regulator , rather than the classic 7805 . We’ve found four different hobbyist-friendly packages for different situations.
A simple voltage divider (R1,R2) sets the LM317 output between 1.25volts and 37volts; use this handy LM317 calculator to find resistor values. The regulator does its best to maintain 1.25volts on the adjust pin (ADJ), and converts any excess voltage to heat. Not all packages are the same. Choose a part that can supply enough current for your project, but make sure the package has sufficient heat dissipation properties to burn off the difference between the input and output voltages.
Schematic of LM317 in a typical voltage regulator configuration, including decoupling capacitors to address input noise and output transients.
The LM317 has three pins: Input, output, and adjustment. The device is conceptually an op amp (with a relatively high output current capacity). The inverting input of the amp is the adjustment pin, while the non-inverting input is set by an internal bandgap voltage referencewhich produces a stable reference voltage of 1.25V. Continue reading
think that it is safe to say that most of the people who make (big or small) electronics-projects have a pc or laptop in theire hobbycorner and a lot of projects need 5V for IC’s or microcontrollers. So using power from a USB cable isn’t that farfetched and lets face it: a lot of devices around us use a USB-connection to get their power or to charge their batteries.
About USB-connectors and power