Archive for the ‘HOWTO’ Category

Raspberry Pi As a Cheap Home Surveillance System

Sunday, January 19th, 2014

CCTV

Home surveillance systems are incredibly expensive, but if you’re looking for more of a DIY approach, Instructables user Scavix shows off how to build your own small-scale system for about $120 using a Raspberry Pi.

Scavix’s system uses a Raspberry Pi, the Raspberry Pi camera module, some housing for that camera, and a few other smaller pieces. After some set up, the end result is a home security system that can detect motion, broadcast a live stream, and more. It’s a surprisingly powerful system all things considered and it’s cheap enough that you can set up a few of them if you like.

Source: Instructables

Israeli Drone Pilots Made Their Life-and-Death Choices Over Gaza, and how?

Saturday, November 24th, 2012

A Heron drone at the Palmahim air base in Israel in December of 2011. Photo: AP/Dan Balilty

The latest round of fighting between Israel and Hamas has settled into an uneasy ceasefire. But that won’t stop Israel’s drones from filling the skies over Gaza. In this 2009 story, written during the final days of the last Israel-Hamas  conflict, we took a look at how one drone pilot grappled with the moral choices that came with remotely spying, and ordering death, from above.

Life or Death choices will never been easier with judgement done through small screen. how these guys, manage doing these task properly or most importantly humanly. Guess, wired have this story covered here. Come on, take a look.

Courtesy: Wired.com

 

Hacking Home Automation Systems Through Power Lines

Saturday, August 13th, 2011



 

X10-Jammer.png

Quoted from Hackaday.com

As home automation becomes more and more popular, hackers and security experts alike are turning their attention to these systems, to see just how (in)secure they are.

This week at DefCon, a pair of researchers demonstrated just how vulnerable home automation systems can be. Carrying out their research independently, [Kennedy] and [Rob Simon] came to the same conclusion – that manufacturers of this immature technology have barely spent any time or resources properly securing their wares.

The researchers built tools that focus on the X10 line of home automation products, but they also looked at ZWave, another commonly used protocol for home automation communications. They found that ZWare-based devices encrypted their conversations, but that the initial key exchange was done in the open, allowing any interested 3rd party to intercept the keys and decrypt the communications.

While you might initially assume that attacks are limited to the power lines within a single house, [Kennedy] says that the signals leak well beyond the confines of your home, and that he was able to intercept communications from 15 distinct systems in his neighborhood without leaving his house.

Can’t imagine how someone disturbing your private time while you’re enjoying your hot bath? think again. have a nice weekend.

Courtesy: Hackaday, Wired

How GPS Bends Time

Saturday, July 16th, 2011

Equation section, WIRED magazine:

GPS-time.png

Einstein knew what he was talking about with that relativity stuff. For proof, just look at your GPS. The global positioning system relies on 24 satellites that transmit time-stamped information on where they are. Your GPS unit registers the exact time at which it receives that information from each satellite and then calculates how long it took for the individual signals to arrive. By multiplying the elapsed time by the speed of light, it can figure out how far it is from each satellite, compare those distances, and calculate its own position.

For accuracy to within a few meters, the satellites’ atomic clocks have to be extremely precise—plus or minus 10 nanoseconds. Here’s where things get weird: Those amazingly accurate clocks never seem to run quite right. One second as measured on the satellite never matches a second as measured on Earth—just as Einstein predicted.

According to Einstein’s special theory of relativity, a clock that’s traveling fast will appear to run slowly from the perspective of someone standing still. Satellites move at about 9,000 mph—enough to make their onboard clocks slow down by 8 microseconds per day from the perspective of a GPS gadget and totally screw up the location data. To counter this effect, the GPS system adjusts the time it gets from the satellites by using the equation here. (Don’t even get us started on the impact of general relativity.)

 

courtesy: wired.com

A GPS without GPS

Monday, July 11th, 2011

gsmlocalizerWow, that sounds weird. It’s actually a mini GSM-based localizer without any GPS devices attached. It’s an old device with the cheaper SimCom module SIM900.  Here is a complete working GSM localizator which is pretty cheap and small too.

As introduction, this system allows localization without directly using GPS technology; we are able to locate the desired object fairly precisely by using database availability together with the geographic position of the cells themselves. In some country the cell coordinates are not publicly known (i.e. in Italy). If so, where do we find such data? Through Google Maps… Google has been able to store billions of data regarding the location of its clients’ cell phones. But how does GSM localization work? The radio mobile network is made up of a number of adjacent radio cells, each of which is characterized by an identifier consisting of four data: a progressive number (Cell ID), a code related to the area in which that given cell is (LAC, or Local Area Code), the code of national network to which the cell belongs (MCC, an acronym for  Mobile Country Code), and finally the company code (MNC, or Mobile Network Code), which obviously identifies the phone company itself. For this reason, once a cell name and coordinates are known, and considering the maximum distance allowed between this cell and a phone  before the phone connects to a new cell, it is possible to find out, approximately, the most distant position of the phone itself. For example, if the maximum distance has been determined to be one mile, the cell phone can be within a one-mile radius. It can be deduced that the more cells are found in a given area, the more precisely one can determine where the phone is located (up to 200-350 feet). The idea of employing only a GSM device to build a remote localization system occurred to us when we realized that Google Maps Mobile, which had been conceived to allow smartphones equipped with a GPS receiver to use Google for satellite navigation, was extended to all cell phones, as long as they were able to support GPRS or UMTS data.  Naturally, this method allows but for a rough estimate: determining the precise position of the cell phone hinges on data regarding the coverage of a given cell which can only be provided by the Google server.

DataCell

The circuit

Compared to traditional localizers based on GPS, this device presents many advantages, primarily because it is lighter and less bulky, has a cost lesser and greater autonomy to exercise. This means that about one battery lithium ion, such as 1 Ah, our tracker can be in operation for several days (it all depends on the number of SMS that have to do). A locator based on cellular network may answare more immediately: the GPS receiver may take several minutes to determine its position. Our tracker works battery and thus can be brought on by people who may have the need to ask help or be tracked, but also placed on board motor vehicles (without installation) or simply introduced in goods in transit. To avoid unnecessarily draining the battery, the localizator provides its position via SMS, on requesto with a simple phone call. Among the functions implemented there is the SOS: By pressing the button the localizator sends a text message asking for help, containing the coordinates of position, the sending can be done to a maximum of eight thelephone numbers. When queried or with the autoreport function, sends an SMS with the localization.To know the location of remote device must send an SMS request cell is connected and sends a request (via GPRS) to Google’s site, the latter responds with the coordinates and the figure for the precision. Everything happens in seconds.

0908_Schema

Well, you can get hell of these stuff from link provided afterward. Design files and the firmware are included. A fun stuff to experiment with at your disposal. Mini GSM localizer without GPS at open-electronics.org.

All images are courtesy of open-electronics.org

A Brief Description of SCADA System Signals

Sunday, June 19th, 2011

It has been a while, I left this site without any updates. So, here I present a basic of a SCADA system signal. It’s basic and have to describe it a way earlier but, left out with an assumption every SCADA engineer should have known it. Anyway, as a general reading, this topic should be one of important information for public readers.

basic circuit of instrument signal tappingThe most common current signal standard in modern use is the 4 to 20 milliamp (4-20 mA) loop, with 4 milliamps representing 0 percent of measurement, 20 milliamps representing 100 percent, 12 milliamps representing 50 percent, and so on. The use of a 4 mA reading to indicate zero is known as “live zero.” This helps to distinguish a zero reading from a “dead signal” or non-functioning equipment. The range of readings possible for a properly functioning system then is only 16 mA (20 mA – 4 mA). This 16 mA range is known as the “live signal.” The actual reading being recorded in mA is called the “process variable.” The PV indicates a percentage of a particular measurement being monitored. The table below shows the relationship between various PVs and their corresponding percentages.

signal comparison tableA convenient feature of the 4-20 mA standard is the ease in converting these signals to 1-5 volt indicating instruments, as the table on the left shows. A simple 250-ohm precision resistor connected in series with the circuit will produce arange of readings from 1 volt of drop at 4 milliamps to 5 volts of drop at 20 milliamps. The current loop scale of 4-20 milliamps has not always been the standard for currentinstruments. In the past, 10-50 milliamp signals were used more frequently. That standard has since become obsolete. The main reason for the eventual supremacy of the 4-20 milliamp loop was safety. Lower circuit voltages and lower current levels (compared to 10-50 mA systems) mean less chance for electrical shock injuries and/or the generation of sparks capable of igniting flammable environments in certain industrial applications.

An Overview of  SCADA Signal Calculations

Definition of terms

Dead signal: A reading from a non-functioning system that can be mistaken for a measurement.
Live signal:
The range of possible process variables. In a 4 – 20 mA system, any signal below 4 mA or above 20 mA indicates malfunctioning equipment. The range of useable signals is between 4 & 20 mA. Therefore, the live signal = 16 mA.
Live zero:
A reading other than zero used to indicate zero so that a zero reading can be distinguished from a dead signal. In 4 – 20 mA systems, the live zero = 4 mA.
PV:
Process variable. The signal reading, in mA, that represents a percentage of a particular measurement.

One of the more common uses for SCADA systems is the monitoring of storage levels. Formulas for making these calculations include:

mA to feet conversion

So, given a SWH of 30 ft, and board reading of 14.67 mA, the water level would be calculated as follows:

water level calculation

Kindly, do enjoy to use or share this information. Have a nice day.

Reference: Water Opcert School

Going cellular with your Arduino projects

Sunday, February 6th, 2011

going-cellular-with-arduino

It will be more interesting if we can get our projects connected, via wires or wirelessly. It can extend the functionality of the project itself. Here, i would like to share some useful stuff in order to add functionalities to your Arduino project.

You can add a huge measure of extensibility to a project by using a cellular connection. Anywhere the device can get service you can interact with it. In the past this has been a pretty deep slog through datasheets to get everything working, but this tutorial will show the basics of interacting with phone calls and text messages. It’s the 26th installment of what is becoming and mammoth Arduino series, and the first one in a set that works with the SM5100B cellular shield.

We love the words of warning at the top of the article which mention that a bit of bad code in your sketch could end up sending out a barrage of text messages, potentially costing you a bundle. But there’s plenty of details and if you follow along each step of the way we think you’ll come out fairly confident that you know what you’re doing. Just promise us that you won’t go out and steal SIM cards to use with your next project. Find part two of the tutorial here and keep your eyes open for future installments.

courtesy hackaday

Save sensor data to Google Spreadsheets by Codebox

Saturday, December 25th, 2010

I found this is really a good way to gather data, since Google Spreadsheets is free and can be accessed from any places in the world as long as connected to the internet. Plus, you can share it with selected persons you want. It’s quite useful for scientific researchers to share and analyze their findings. Check this out (completed with the codes):

The “Hello Arduino” section in Chapter 11 of Getting Started with Processing shows how to read data into Processing from Arduino. In a nutshell, the Arduino code (example 11-6 in the book) reads data from a light sensor and writes it out to the serial port. The section then goes on to describe a number of increasingly sophisticated sketches that retrieve and visualize the sensor data using Processing’s Serial library.

This Codebox shows you how to save this sensor data to a Google Spreadsheet. The cool thing is that you can then use any of the goodies that Google provides (charts, gadgets, maps, etc) directly with your data. While the light sensor is pretty basic, you can use this basic setup to record data from more sophisticated sensors, such as a Parallax GPS receiver module into Google Spreadsheets, and then create a map of where you’ve been that you could post as a gadget.

The sketch relies on the Google API Client Library for Java, which is a set of code libraries for interacting with various Google’s services (not just Spreadsheets). In researching this article, I found Processing guru Jer Thorpe‘s article Open Science, H1N1, Processing, and the Google Spreadsheet API a great inspiration. While it’s based on an older version of the API (version 1.0, while the APIs are now up to version 3.0), it’s a great introduction to interacting with Google.

Courtesy Make

GardenBot Is Monitoring Your Garden

Sunday, November 28th, 2010

how-to_module-map courtesy of gardenbot.org

Amazing work, and very interesting solution (of an experience of nature-lovers and DIYers) to keep an eye on your garden:

GardenBot is a garden monitoring system. This means that you put sensors in your garden, and GardenBot will show you charts of the conditions in your garden — so you can see the world the way your plants see it.

I did… er, I mean hi. My name is Andrew Frueh. Me and my wife, Melissa, like to garden a lot. We’re always experimenting with different methods in our garden and compost. We already were using a soaker hose for our garden. Last year, we used one of those mechanical timers to turn the soaker on for a pre-determined amount of time. But then…
I discovered Arduino, and immediately became engrossed. Arduino is a little computer (called a microcontroller) about the size of a business card. It has a bunch of analog and digital inputs/outputs so you can hook up various sensors, buttons, switches, audio/video devices — it’s pretty friggin’ cool. See the parts page for more information.
Anyway, considering my interests, I thought “gee, it sure would be neat to use the Arduino board to control the watering in the garden”. But then one thing led to another… and now we get to the (somewhat complete) GardenBot system that you have before you.
Like a lot of DIY-ers, I am entirely self-trained. So, there are a lot of holes in my knowledge. As I hunted around for information on the web, I found that too often the information in various tutorials was written by someone who failed to remember that lay-people (incidentally the target audience for any tutorial) don’t know the jargon, and therefor can have great difficulty in decoding the information. One of my goals with this project, is to have all the pieces laid out in plain language — step by step — to walk you through the whole process. Hopefully I pull that off.

check out the web, as all the resources and methods are well documented. Good job!

courtesy: gardenbot.org

Wirelessly Automate Your Home

Sunday, November 14th, 2010

home-automation-via-router.png

I’ve stumbled across this quite simple idea of home automation using Wifi. [Mrx23] combined OpenWRT, a microcontroller, and a set of RF controlled outlet switches to add automation to his plug-in devices. An RF remote that controls the switched outlets has been connected to an Arduino. The router communicates with the Arduino via a serial connection. And the router is controlled by a web interface which means you can use a smartphone or other web device to control the outlets.

The best thing about this system is the power that the router wields. Since it has an underlying Linux kernel you have the option of setting CRON jobs to turn lighting on and off, and group settings can be established to set up a room’s lighting level for watching movies, hosting guests, etc. Combine this with the fact that OpenWRT can use port forwarding for Internet control and the possibilities really start to open up.

Courtesy Mrx23 at Instructables.com