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Linux video camera security

Part I

Our commercial video surveillance system had a problem last week. The mains supply unit that feeds the camera, which in turn uses a CCD (Charge Coupled Device) and transmits to the receiver through microwave (2.4 GHz) had failed. To add to our woes, the multiple camera switcher unit had failed as well – possibly owing to a disastrous power supply fault.

It would take some time to sort out this issue and procure replacement units to handle the security of the premises. Someone suggested that we explore using the ubiquitous webcams lying around in our office, coupled with some open source (or commercial) software to handle the perimeter security.

A quick search in the Google for the term – “linux video camera security” returned some 9 million pages. Zoneminder appeared to suit our requirement though our needs were more modest. The site mentions that it is a complete “ all in one Linux GPL’d security camera solution” .

Basically what we needed was as enumerated below:

Option of using inexpensive USB webcams
Option of using a Multi camera setup
Software driven Motion detection
Video streaming through the Net
Option of storing the images generated in the high capacity Network File Server

Browsing through the supplied manual (readme.pdf) showed that Zoneminder would more than suit our requirements.

There are many ways you can download and install the software package.

You can download and compile the source code or download your distro specific RPM to install. You will find that most of the code is written in Perl, which makes managing/ fault finding that much easy for people conversant with Perl.

Linux Video camera security

You will need amongst other things – an Apache server with PHP and Mysql installation. There are other essentials too – libjpeg.a , libpcre.a , ffmpeg or the Berkeley MPEG encoder – if you plan to generate MPEG video. Fortunately if you are with any modern distros, you can use any of their built-in updating to obtain the required libraries.

We will explore how we built from the ground up a very versatile video camera security system with little more than a Linux box and a few readily available Webcams in our subsequent parts.

Targetwoman Earth Day Celebration

We join the Earth day celebration in a small way – by our efforts to disseminate information about practical conservation and tips on Energy saving. Global warming has become a mantra in the media now. Steps to reduce the production of CO2 (carbon dioxide) that contributes to the global warming by the Green House effect can be attempted by anyone who has an interest in preserving Mother Nature.

We provide below some tips and guidance on Energy Conservation:

1. Air conditioning and Heating: Different people require different temperature settings for comfort. We feel comfortable when our bodies lose heat at the same rate as we produce it. Heat production varies with physical activity and our metabolic rates. At the same time, heat loss or heat gain depends on surface temperatures in the room, air movement and air temperature. What all this means is that your comfort factor depends on a lot of factors – one of which is the temperature. Start by setting your thermostat a couple of degrees low.

Energy Efficiency Rating: The energy efficiency rating (EER) of an air conditioner is its BTU rating over its wattage. For example, if a 10,000-BTU air conditioner consumes 1,200 watts, its EER is 8.3 (10,000 BTU/1,200 watts). Aim for a higher EER. Turn off the unit when no one is present. If you have a Voltage regulator for pre-conditioning the supply, turn that off as well.

Better Thermal Insulation: A false ceiling with better heat insulation efficiency can reduce as much as 20 % power bills. An energy-efficient house has a much higher insulation value. It has the ability to resist heat transfer and fasten the heat loss. Materials that weigh a lot store more heat and have high thermal mass. Use of such materials can reduce heating and cooling energy requirements by nearly 25% as compared with mere brick veneer houses.

Power Factor Correction: All electric motors consume reactive power from the supply. Power factor correction capacitors correct the anomaly in the power supply. Discuss with your electric contractor the size of the power factor correction capacitor and its installation. It could save about 10 % from your utility bills.

2. Replace all incandescent bulbs with CFL (compact Florescent Lamps). CFLs are very energy efficient. A 15 W CFL will provide the same amount of illumination as a 60 W normal bulb. But they can’t be dimmed using conventional dimmers. Clean all lamps and lamp shades periodically. A clean lamp and a clean lamp shade enhances light transmission.

3. Inflate your automobiles tires to the manufacturer recommended pressures. Inadequate pressure in your tires can increase rolling resistance by as much as 20 %. Combine trips and chores so that you save on precious fuel. Remove top carriers when not required. They increase wind resistance. Drive at a sedate speed to improve your mileage.

4. Turn off your computers and monitors when not in use unless you are running a data center. A typical Switch Mode Power Supply (SMPS) of a desk top computer consumes about 400 W of energy most of the time. Use a TFT LCD monitor if you are using the conventional CRT (Cathode Ray Tube) monitor. A typical 17 inch CRT monitor consumes about 120 W while the same sized LCD monitor takes in about one fourth of the energy. The heat produced by the CRT also heats up the neighborhood adding to the cooling cost.

5. Invest in automation. A PIR (Passive Infra Red) movement sensor based outdoor lighting can help save considerable energy. You can use them in aisles and elsewhere where manual switching on and off of lights is inconvenient. You will find more tips in energy saving in our article.

Spread the word around.

Handywoman Basic Tools 3

We have covered the basic but most essential tools earlier. The list is not exhaustive and a whole lot depends on the type of job you plan to undertake. For most household repairs and the odd job in your car, you can make do with the tools we list here.

Utility Knives: Utility Knife comes in many shapes. Most use replaceable blades. When the tip of the blade loses its sharp edge, break it off with a pliers, observing standard precaution – Keep the knife away from the body and your face. The broken metal can fly off …

Electric Drill : Electric mains operated drills have more torque than their cordless cousins of similar sizes. But cordless drills are versatile and can be used anywhere without tethering to a mains outlet. Drills have amazing varieties of attachments – from buffing to sharpening your knives – you can use your ubiquitous drill.

Keep the batteries always charged when not in use to conserve the battery life. Most cordless drills are powered by Nickel cadmium batteries, which tend to lose their capacity when made to sit under discharged conditions.

Tapes: Keep a stock of electric insulation tape, duct tapes and measuring tapes handy in your tool kit. Remember to encase any temporary electrical connection joints in insulation tape. It is never pleasant to receive electric shocks …

Multimeter: This comes in handy to test for many electrical / electronic works – from testing continuity in circuits to measuring the current or measuring the voltage at the outlet. Again these meters come in many sizes with varying capabilities. A simple digital multimeter (DMM) capable of measuring upto 20 Amp AC/DC current will be adequate for most purposes. They can measure with adequate precision volts up to 900 or higher. They can beep or buzz when the prods are shorted or when there is continuity up to a few Ohms.

There was a time people used analogue meter movements in the Volt Ohm Meter (VOM). These meters use D’Arsonval Meter Movements, which are very sensitive and need careful handling as they use jeweled bearings. And they cost a packet of money. With the advent of digital revolution, digital meters have become insanely cheap to own.

Ensure that you have set the meter to the right function before connecting the prod. When you select the function to read the current and apply the prods directly across the mains supply – you are causing a direct short in the mains supply !

Currents are always measured in series with the equipment and the supply. Voltages are measured across the source. Switch off the mains when you test for continuity.

Find a good toolbox to store your collection of tools. Smear thin grease on the movable joints of tools. But the handle sections must never be greasy or be smeared with oil.