Thermostat remote temperature sensor hack

Alan Parekh of Hacked Gadgets writes: We all have thermostats in our houses but how often are they in a horrible place? You often want to place the temperature sensor in a different location than the control and display unit. There are lots of models that have remote sensor capability but they come with a […]

Hard disk drive clock with Arduino Uno

ACVoltage  wrote this instructable detailing his DIY POV clock using hard disk drive and Arduino Uno: This is a fun project that can be done easily and also cheaply. In this instructable we will explain step by step how to make this beautiful POV clock. Used material: -Arduino Uno, -Tiny RTC modul, -ULN 2003, -IR diode and IR transistor […]

Arduino ultrasonic range finder, with I²C lcd display

An Arduino rangefinder with an ultrasonic sensor and an I²C interface display by Jan Henrik. He wrote an instructables here: The maximum rated range is 500 cm, the range is measured 20 times per seccond. It is Displayed on a lcd screen which is 20×4 chars big, it has a custom start message, and it can […]

Reverse engineer wireless temperature / humidity / rain sensors, part 1

Ray Wang writes: I just wrote a series of three posts about how I reverse engineered a few off-the-shelf wireless temperature, humidity sensors and rain gauge, and used an Arduino to listen to and decode the sensor data. The tools involved are quite simple: an Arduino and a 433MHz RF receiver. I also used a […]

App note: MAX31730 3-Channel remote temperature sensor

Here’s an application note from Maxim on triple remote temperature sensor: The MAX31730 temperature sensor monitors its own temperature and the temperatures of three external diode-connected transistors. The operating supply voltage is from 3.0V to 3.6V. Resistance cancellation compensates for high series resistance in circuit-board traces and the external thermal diode, while beta compensation corrects for temperature-measurement […]

CO2 meter using NDIR infrared MH-Z14 sensor library for AVR ATmega

Davide Gironi writes: MH-Z14 NDIR Infrared gas module is a common type, small size sensor, using non-dispersive infrared (NDIR) principle to detect the existence of CO2 in the air, with good selectivity, non-oxygen dependant and long life. MH-Z14 has a PWM output, with a sensitivity range of 0ppm to 2000ppm CO2, an accurancy of ±200ppm. […]

An Ultrasonic eye for the visually impaired

Dhavalis build this Netra project, an ultrasonic eye for the visually impaired: Netra is an eye for visually impaired, a device based on Echolocation principle. It uses Arduino Micro, Ultrasonic sensor and vibrating motor. Vibration of the motor increases with decrease in distance and vibration decreases with increase in distance between device and object in front. […]

Ambient Backscatter – Wireless power and communication with no batteries

Ambient Backscatter – Wireless power and communication with no batteries Ambient Backscatter transforms existing wireless signals into both a source of power and a communication medium. It enables two battery-free devices to communicate by backscattering existing wireless signals. Backscatter communication is orders of magnitude more power-efficient than traditional radio communication. Further, since it leverages the […]

Power efficient, adjustable, light-sensitive switch using an LED

Power efficient, adjustable, light-sensitive switch using an LED: You can use an LED as a photoelectric sensor. A previous Design Idea shows that such a switch is highly power-efficient, consuming almost no power (Reference 1). However, you cannot adjust that configuration to switch at the desired light intensity. You can adjust the circuit in this […]

Raspberry Pi irrigation system rain bypass

This web-enabled rain sensor will automatically turn-off an irrigation system when it rains using a Raspberry Pi: This Raspberry Pi Irrigation System Rain Bypass uses a web connected Raspberry Pi to look up rain predictions and disable the irrigation system from watering the lawn if it won’t be necessary.  The existing controller has an input […]