Ray has a great reverse engineering project! Check out more on his blog rayshobby.net. [via]
At the Maker Faire this year I got lots of questions about soil moisture sensors, which I knew little about. So I started seriously researching the subject. I found a few different soil sensors, learned about their principles, and also learned about how to make my own. In this blog post, I will talk about a cheap wireless soil moisture sensor I found on Amazon.com for about $10, and how to use an Arduino or Raspberry Pi to decode the signal from the sensor, so you can use it directly in your own garden projects.
What is this?
A soil moisture sensor (or meter) measures the water content in soil. With it, you can easily tell when the soil needs more water or when it’s over-watered. The simplest soil sensor doesn’t even need battery. For example, this Rapitest Soil Meter, which I bought a few years ago, consists of simply a probe and a volt meter panel. The way it works is by using the Galvanic cell principle — essentially how a lemon battery or potato battery works. The probe is made of two electrodes of different metals. In the left picture below, the tip (dark silver color) is made of one type of metal (likely zinc), and the rest of the probe is made of another type of metal (likely copper, steel, or aluminum). When the probe is inserted into soil, it generates a small amount of voltage (typically a few hundred milli-volts to a couple of volts). The more water in the soil, the higher the generated voltage. This meter is pretty easy to use manually; but to automate the reading you need a microcontroller to read the value.
Reverse engineer a cheap wireless soil moisture sensor using Arduino or Raspberry Pi - [Link]
by MakerSpark Industries @ instructables.com:
This Instructable is about how to create an Arduino PIR motion sensor for your room or office, using parts available from your local Radio Shack! Whether you’re looking for a cool and easy-to-build security sensor, or an awesome first project to dive into the world of Arduino, Microcontrollers, and electronics, this project is for you. (This project really is easy. Take it from me, I’m 12, and I’ve only had my Arduino for a week and a half.)
Arduino PIR Motion Sensor - [Link]
by Steve Taranovich @ www.edn.com:
Freescale Semiconductor introduced the MM9Z1J638, AEC-Q100 qualified intelligent battery sensors with three measurement channels, a 16/32-bit MCU and a CAN protocol module in one 7 x 7 mm 48-pin QFN package.
The market this product serves is quite diversified with 12 V lead acid batteries, 14 V Li-Ion batteries, Lead acid multi-batteries, HV battery junction box, Energy Storage Systems (ESS), Uninterrupted Power Systems (UPS) and industrial automation.
Today’s trends in the battery market include complex battery algorithms, higher communication data rates with the CAN bus, better safety for Li-Ion batteries and increased mission-critical dependence on energy availability.
Start-stop requirements, together with others such as regenerative braking and intelligent alternator control, are driving demand for more precise sensing of the battery’s state to provide early failure warnings.
Intelligent battery sensor for automotive and industrial - [Link]
Ondrej Karas of DoItWireless writes:
This article describes temperature and humidity measurement with DHT11 sensor connected to TR module. Circuit diagram is very simple. You need only power supply for sensor and one wire for data line. This line has to be “pull-uped” – sensor has open collector output.
Temperature and humidity measurement with DHT11 - [Link]
I recently stumbled across an interesting fact in the datasheet for the ATMEGA32u4, the microcontroller I am using for my Einstepper Project. I was surprised to find that Atmel had included a temperature sensor in the core of the device that you can read using the internal ADC. As it turns out, there are many megaAVR devices contain an internal temperature sensor. According to Atmel’s product finder, these devices are:
ATMEGA Core Temperature Sensor - [Link]
by Nancy Owano @ phys.org:
Sony’s advance in image sensors appears quite natural: the company has developed a set of curved CMOS image sensors based on the curvature of the eye. A report on the sensors in IEEE Spectrum said that, “in a bit of biomimicry,” Sony engineers were able to achieve a set of curved CMOS image sensors using a “bending machine” of their own construction.
Sony inspired by biomimicry develops curved CMOS sensors - [Link]
by brmarcum @ instructables.com:
I hate Christmas tree lights.
Well not really, I just don’t enjoy having to climb under the tree every time I want to plug in or unplug the lights. In the interest of saving my sanity, I decided to build a motion activated switch that can power the lights for me. It has an integrated adjustable timer so they will stay on for as long or as short as I want. Here’s a video showing the final test on the fish tank light.
Motion Activated AC Switch - [Link]
Shabaz over at Element14 writes:
This post is about an interesting, low-cost sensor that doesn’t need much processing to use, and has some unique characteristics – a PVDF (polyvinylidene difluoride) Piezoelectric sensor. The sensors looks like a small strip of plastic, and can be used for detecting movement or vibrations even into ultrasound. Such devices can help sense in many practical, real-world scenarios. They are extremely sensitive, low cost and easy to use. Some simple practical experiments with these sensors are described, finally looking at detecting ultrasound.
Impact, vibration and ultrasound sensing with PVDF Piezo sensors - [Link]
By European Editors
Air pollutants such as particles and noxious gases are known to be harmful to human health. In industry, on the other hand, high concentrations of gases such as methane or propane, or carbon monoxide resulting from poor combustion processes, can present an immediate safety risk. To overcome these problems, a wide range of groups such as homeowners, operators of commercial buildings or industrial sites, city councils, and environmental agencies need access to equipment for monitoring air quality and detecting the presence of various gases.
Sniffing the Air: Sensors for Monitoring Air Quality and Safety - [Link]
ICStation @ instructables.com writes:
ICStation team introduce you how to DIY this temperature & humidity & smoke alarm system based on ICStation Mega 2560 compatible with Arduino.The working voltage of this system is DC5V.It can measure the current temperature, humidity and smoke. It can display real-time data by the 1602 LCD and can realize the sound and light alarm when in the dangerous temperature and humidity. It is a simply and easily to operate monitoring alarm system about temperature humidity and smoke.
DIY Temperature & Humidity & Smoke Detector - [Link]