How to Make an Arduino Door Alarm Using an Ultrasonic Sensor
https://makerv2.webteractive.co/arduino/projects/arduino-door-alarm-using-ultrasonic-sensor
Use an Arduino and an ultrasonic sensor to make a door alarm that sounds when someone comes within a certain distance.
How to Make an RFID Arduino Door Lock
https://makerv2.webteractive.co/arduino/projects/how-to-make-an-rfid-arduino-door-lock
Learn how to make an RFID door lock powered by an Arduino and solenoid engine.
How to Make an Arduino Keyless Door Lock System With Keypad and LCD
https://makerv2.webteractive.co/arduino/projects/arduino-keyless-door-lock-system-keypad-lcd
Use an Arduino to make your own keyless door lock system with LED display.
How to Make an Arduino Keypad Door Lock With Micro Linear Actuator
https://makerv2.webteractive.co/arduino/projects/arduino-keypad-door-lock-micro-linear-actuator
Use this discreet bolt system to open and close just about anything only after a PIN entry on a keypad.
How to Create a Facial Recognition Door Lock With Raspberry Pi
https://makerv2.webteractive.co/raspberry-pi/projects/how-to-create-a-facial-recognition-door-lock-with-raspberry-pi
Use a Raspberry Pi camera and a solenoid lock to create a door lock that unlocks when it recognizes your face!
How to Make an Earthquake Early Warning Alarm
https://makerv2.webteractive.co/arduino/projects/earthquake-alarm-system
Make an earthquake early warning system with an Arduino, littleBits, Ruby, and PubNub.
How to Make a Laser Diode Tripwire Alarm With Launchpad
https://makerv2.webteractive.co/ti-launchpad/projects/laser-diode-tripwire-alarm-with-launchpad
Create an alarm that sounds off anytime something crosses through the laser.
How to Make an Arduino Alarm Clock Using a Real-Time Clock and LCD Screen
https://makerv2.webteractive.co/arduino/projects/arduino-alarm-clock-using-real-time-clock-lcd-screen
Make your own Arduino alarm clock using a DS3231 real-time clock module.
How to Make an Analog Alarm System With a TI LM386 Power Amp
https://makerv2.webteractive.co/analog/projects/diy-analog-alarm-system-ti-lm386-power-amp
This device will make a loud and annoying sound when somebody moves an object off of the pad.