The heart rate, also referred to as pulse rate, has been recognized as a vital sign since the beginning of medicine, and it is directly related to a person’s cadiovascular health. Today, we are going to make a PC-based heart rate monitor system using an Arduino board and Easy Pulse V1.1 sensor. Easy Pulse is a pulse detecting sensor that uses the principle of transmission photo-plethysmography (PPG) to sense the pulse signal from a finger tip. The sensor output is read by the Arduino board, which then transfers the data to the PC through a serial interface.
Inside larger seven segment LED modules, the display segments are made of multiple LEDs connected in series and parallel to provide sufficient light to illuminate the segment, and as such they require a higher forward voltage and more current to operate. Recently, I have designed this display driver board that can be used as a bridge in between larger seven segment LED displays (with segment forward voltage up to 24V) and Arduino. On its input side is MAX7219 which receives the display data from the host microcontroller through a 3-wire SPI bus.
A light meter is a device that measures the intensity of light. It finds applications in schools, hospitals, production areas, passageways and more to measure and maintain proper lighting levels. It is often used by photographers to determine the proper exposure for a photograph. Today we are going to build a simple light meter using an Arduino board and a BH1750 digital light sensor. The measured lighting level or intensity is displayed on eight seven segment LED displays, in both Lux and Foot-candle units.
MCP9802 is a digital temperature sensor from Microchip that measures temperatures between -55°C and +125°C to a digital word. It provides an accuracy of ±1°C (maximum) from -10°C to +85°C. The MCP9802 sensor comes with user-programmable registers that provide flexibility for temperature sensing applications. The register settings also allow user-selectable 9-bit to 12-bit temperature measurement resolution. This sensor has an industry standard 2-wire I2C compatible serial interface, allowing up to eight devices to be controlled in a single serial bus. In this blog post I am going to write about an Arduino sketch to interface the MCP9802 sensor with an Arduino for temperature sensing application.
In this blog project, I am providing you step by step instructions to build a very simple temperature and relative humidity meter for indoor use. All you need to build this project are an Arduino Uno or compatible board, a DHT11 sensor, and a MAX7219 based 8-digit serial 7-segment LED display. The temperature is displayed in degree Celsius and relative humidity in percentage.