by Michael Mayes @ edn.com:
Although temperature is a fundamental aspect of our lives, it is difficult to measure accurately. Before the era of modern electronics, Galileo invented a rudimentary thermometer capable of detecting temperature changes. Two hundred years later, Seebeck discovered the thermocouple, a device capable of generating a voltage as a function of temperature gradients in dissimilar metals. Today, thermocouples as well as temperature dependent resistance elements (RTDs and thermistors) and semiconductor elements (diodes) are commonly used to electrically measure temperature. While methods for extracting temperature from these elements are well known, accurately measuring temperatures to better than 0.5ºC or 0.1ºC accuracy is challenging (see Figure 1).
Temperature-to-Bits converter helps solve challenges in sensor measurement - [Link]
praveen @ circuitstoday.com:
This article is about interfacing gyroscope to arduino. Gyroscope is a device used for measuring the angular velocity in the three axes. It works under the concepts of angular momentum and can be used to determine the orientation of an object. Typical applications of gyroscope includes missile guidance, flight control, smart phones, game station joy sticks etc. Mechanical gyroscopes, MEMS gyroscope, optic fiber gyroscope, ring laser gyroscope.
Interfacing gyroscope to arduino - [Link]
RTC or real-time clock is a kind of computer clock for keeping track of the recent or most current time. Commonly, RTCs are present in almost all or any device, which are electronic in nature that needs to keep time accurate. Meanwhile, temperature sensors are devices that gather data concerning the temperature from a source and convert it to a form that can be understood either by an observer or another device. These sensors can be in various forms and are used for a wide variety of purposes, from simple home use to extremely accurate and precise scientific use. They play a very important role almost everywhere that they are applied; knowing the temperature helps people to pick their clothing before a walk outside just as it helps chemists to understand the data collected from a complex chemical reaction.
The circuit uses a PCA8565 CMOS real time clock and calendar optimized for low power consumption. A programmable clock output, interrupt output and voltage-low detector are also provided. All address and data are transferred serially via a two-line bidirectional I2C-bus with a maximum bus speed of 400kbit/s. The built-in word address register is incremented automatically after each written or read data byte. It also includes a MCP9801 digital temperature sensor capable of reading temperatures from -55°C to +125°C. Temperature data is measured from an integrated temperature sensor and converted to digital word with a user selectable 9 to 12 bit Sigma Delta Analog to Digital Converter. The MCP9801 notifies the host controller when the ambient temperature exceeds a user programmed set point. The ALERT output is programmable as either a simple comparator for thermostat operation or as a temperature event interrupts. Communication with the sensor is accomplished via a two-wire bus that is compatible with industry standard protocols. This permits reading the current temperature, programming the set point and hysteresis and configuring the device. Address selection inputs allow up to eight MCP9801 sensors to share the same two-wire bus for multizone monitoring. Small physical size, low installed cost and ease of use make the MCP9801 an ideal choice for implementing sophisticated temperature system management schemes in a variety of applications.
The board is basically a carrier for the two IC’s that make up the Real Time Clock (RTC), PCA8565 and the Digital Temperature Sensor, MCP9801. It conveniently combines the two for applications that require RTC and temperature sensing. A particularly useful feature of this RTC is that it can detect power down and record the time at that event. This is ideal for connecting to a microcontroller that does not have an RTC.
I2C Temperature Sensor & Real Time Clock - [Link]
by amandaghassaei @ instructables.com:
I’m working on a project that requires full orientation information, so I built an Inertial Measurement Unit from scratch. I really like the 9DOF IMU board that Sparkfun makes – the calibration code that comes with it is fantastic – but I wanted to redesign the board so that it could be made at a much lower price using a single-sided PCB mill. I think the electronics come out to about $20 for this project. All the code, schematics, and PCB milling files are up on github (click the cloud-shaped button to download).
“9 Degrees of Freedom” IMU - [Link]
by willseph @ imgur.com:
The web interface allows me to change the settings on my thermostat remotely, such as the set temperature range compressor and fan modes, as well as view any warning messages that may be reported.
It’s not exactly beautiful, but I’m a function-over-fashion person. The Raspberry Pi is in the middle, white power cable running down and a GPIO rainbow ribbon cord heading up to the relay module under the real thermostat.
Homemade Raspberry Pi smart thermostat - [Link]
Smoke detector is a device incorporated on fire alarm system; it is usually installed on buildings to alarm the occupants when there is a fire (when there’s smoke, there’s fire). This provides the crucial early warning to escape injury or death in fire. This project uses optical method design; the sensing part is the photo chamber that is composed of infrared light source and a photoelectric receiver (photodiode).
The design of this project is not so complicated because of the specialized IC (Integrated Circuit) intended for smoke detection. The RE46C190 smoke detector IC provides all the required features for a photoelectric smoke detector type of electronic project with minimal external component needed. During standby mode, the RE46C190 IC is programed to check the battery condition every 86 seconds and the chamber integrity every 43 seconds. Interconnection between multiple detectors (through I/O PIN-12) is also possible; this will activate all the connected detectors when one of the units is triggered.
The 1µF capacitor should be located as close as possible to the device power pins, and 10µF capacitor should be located as close as possible to VSS. Schottky diode must have a maximum peak current rating of at least 1.5A. For best results, it should have a forward voltage specification of less than 0.5V at 1A and low reverse leakage. Also, the 10mH inductor must have a maximum peak current rating of at least 1.5A. With the IC’s very low power consumption, this project only requires a three-volt DC power supply (simply use a 3 volt battery).
Photoelectric Smoke Detector – [Link]
I recently got my hands on a pair of Flir Lepton thermal imaging sensors and have spent the last week bringing them online in my spare time. These are absolutely incredible devices that I believe will pave the way to consumer devices incorporating thermal imaging cameras. The footprint of the camera module (and optical assembly) is about the size of a dime. The resolution is 80×60 at 14bpp which is remarkable despite sounding low.
Flir Lepton Thermal Imaging Sensor + Gameduino 2 - [Link]
by marc2203 @ importhack.wordpress.com:
I’m not going to explain in detail what is ESP8266 because if you have found this post I’m sure you already know it. But just in case, it is an awesome cheap board (less than 4$) with built-in wifi communication (802.11 b/g/n), and SPI, UART. You can also use its processor to run your code.
How to use ESP8266 ESP-01 as a SENSOR web client - [Link]
by praveen @ circuitstoday.com:
A simple LPG sensor using arduino is shown in this article. This circuit indicates the amount of LPG in the air. The circuit sounds an alarm and trips a relay when the concentration is above a predetermined level. MQ2 is the gas sensor used in this project. MQ2 is an SnO2 based gas sensor which can sense gases like methane, propane, butane, alcohol, smoke, hydrogen etc. Since LPG primarily contains propane and butane, MQ2 sensor can be used for sensing LPG. The figure below shows the schematic and arrangement of an MQ2 gas sensor.
LPG sensor using arduino - [Link]
BITalino is designed for anyone interested in building self-tracking applications based on information from your body.
BITalino is a low-cost, purpose-built, all-in-one hardware and software toolkit designed for quick and easy creation of cool projects with body signals, development of quantified self wearable devices or apps, and/or learning how to build medical devices. Comparative professional-grade tools for this purpose can easily cost in excess of $10,000; our vision is to make them available for anyone, and harness the power and creative thinking of the open-source movement to boost innovation in biosignal-based applications in unprecedented ways.
BITalino (r)evolution - [Link]