Water level controllers are useful devices. In this water level indicator and controller project we are going to use an Arduino board and ultrasonic sensor to measure the water level in a tank. We will also start the water pump automatically when water level goes low below a certain preset level.

In this project, we have built an Arduino based heartbeat monitor which counts the number of heartbeats in a minute. Here we have used a heartbeat sensor module which senses the heartbeat upon putting a finger on the sensor.

The same is also true for keeping items cool – it can be wasteful to run a whole fridge just to make yoghurt – but with a temperature controller, the principle is the same. Instead of activating a heating element, you’ll be activating the plug on a mini-fridge or other cooling element, like a Peltier (thermoelectric cooler) – and of course, the logic will be reversed.

In this project we are going to interface a ROTARY ENCODER with ARDUINO. ARDUINO UNO is an ATMEGA controller based development board designed for electronic engineers and hobbyists. In ARDUINO we have 20 I/O pins, so we can program 20 pins of UNO to be used as either input or output.

Today I decided i wanted to build an alarm for my room, when I searched online all door alarms used the PIR sensor, unfortunately mine was faulty.

and that"s when I decided to build my own alarm using an ultrasonic sensor (HC-SR04),and I found out it was really simple.