What is the difference between mechanical engineers and civil engineers?
Mechanical engineers build weapons. Civil engineers build targets.
Continue reading “Technical Jokes and Cartoons 8”Technical Jokes and Cartoons 8
Understanding IP Camera Specifications, What’s Important
This article was updated on 4/12/2018 to reflect new IP cameras
IP Camera manufacturers provide product specification sheets that help you select the right camera for your IP security and surveillance system. But, which specifications are important? They include such things as resolution, minimum light sensitivity, lens, WDR, signal to noise, etc. This article reviews the important camera specs, and how to avoid being fooled by specsmanship (from the marketing department).
The importance of each of the camera specifications depends on your objective and application for your IP camera system. For example, if you want to use the camera outdoors where it can get dark, then the low light specification is important.
If you are only using the IP camera indoors, you may be more interested in the how wide a viewing angle you can achieve. Here is a review of the important specifications.
Continue reading “Understanding IP Camera Specifications, What’s Important”Calculating the Wire Gauge for Power to Your Device
How do you get the power from here to there?
A number of people have asked us about the gauge of wire required between a device and the power supply. They also want to know how far away these two devices can be. This article describes how to select the right wire and calculate the maximum length of the wire.
Your surveillance IP camera, electric door lock, an audio amplifier, or even an electric heater needs a certain voltage and current to operate. When the power is transmitted across a wire there is a voltage drop caused by the resistance of the wire. If the surveillance camera (the load) is 500 ft. away from the power supply (the source), and it requires 12 VDC, what type of wiring is required to assure that the device gets the right power?
You could always use a very thick wire (low gauge), but that can cost a lot more than thinner wire (high gauge). To calculate the right wire and length you first need to understand a few electrical engineering concepts and equations.
Continue reading “Calculating the Wire Gauge for Power to Your Device”Technical Jokes and Cartoons – 7
A priest, a doctor, and an engineer were waiting one morning for a particularly slow group of golfers. The engineer fumed, “What’s with those guys? We must have been waiting for fifteen minutes!”
The doctor chimed in, “I don’t know, but I’ve never seen such inept golf!”
The priest said, “Here comes the green-keeper. Let’s have a word with him.”
He said, “Hello George, what’s wrong with that group ahead of us? They’re rather slow, aren’t they?”
The greenskeeper replied, “Oh, yes. That’s a group of blind firemen. They lost their sight saving our clubhouse from a fire last year, so we always let them play for free anytime.”
The group fell silent for a moment.
The priest said, “That’s so sad. I think I will say a special prayer for them tonight.”
The doctor said, “Good idea. I’m going to contact my ophthalmologist colleague and see if there’s anything he can do for them.”
The engineer said, “Why can’t they play at night?”
Continue reading “Technical Jokes and Cartoons – 7”
Calculating What You Can See With Your IP Camera
What is the right lens and resolution for your IP camera? When you put together your IP camera system, you want to make sure that the camera you select for each location meets your expectations. It is important to first know the objectives for each area you are viewing. Do you want to identify a person’s face, a license plate, or just detect a person walking far away? In general, the more detail you want, the higher the resolution you need. This article shows you how to determine the viewing area and distance you should expect.
Note: this article was updated on 8/15/2017 to correct an error in calculation.
Continue reading “Calculating What You Can See With Your IP Camera”Technical Jokes and Cartoons 6
Head to Head Comparison of Sony and Axis Dome IP Cameras
We are often asked, what is the best IP camera for my security or surveillance system? Over the last year, we tested a number of different IP cameras. We compared their published specifications and more importantly how they actually performed in our tests. We found that sometimes the less expensive camera can be a much better value.
In the following head to head test, we compared the Sony SNC-VM601 to the Axis P3384V. Both of these dome IP cameras have similar specifications and provide the latest wide dynamic range (WDR) capability. The test determined which camera provided the best value and performance.
We compared camera resolution, low light sensitivity, wide dynamic range, and actual usage in a specific application. Of course, these are not the only characteristics to consider, but we have found these to be the most important in many applications. Here are the results:
Continue reading “Head to Head Comparison of Sony and Axis Dome IP Cameras”How Motion Detection Works in IP Camera Systems
Many IP cameras include motion detection capability. It is also available using video management software (VMS) or a network video recorder (NVR). This is a very important analytic function because it controls when an alarm is triggered and when the video is recorded.
Motion detection seems to be a simple concept. All we do is compare one frame to another and look for things that change. For example, a moving white ball can trigger an alarm by comparing two frames.
Well, it isn’t that simple. The early engineers who worked on motion detection discovered that this was a difficult engineering problem. Back in the 1970’s, I worked on a project to detect moving particles in fluids. What I discovered was that it is sometimes difficult to discern the difference between a moving object and signal noise.
Continue reading “How Motion Detection Works in IP Camera Systems”What is the Right Sound Level for Your Paging Speakers?
Whether it’s an emergency announcement or page in a school, how do you determine the speaker and amplifier required for a specific location? IP paging systems can provide exactly the right sound level to exactly the right location, but what is the right sound level?
How loud does the emergency paging system need to be? How much sound is needed to hear an announcement in a classroom or in a sports field where there is a lot of background noise?
This article provides the technical background and practical information needed to help you determine the right power and speakers required.
Technical Jokes and Cartoons 5
Actually many of these jokes are not really technical, but us tech guys think they’re funny…
Answering machine message,
“I am not available right now, but thank you for caring enough to call.
I am making some changes in my life. Please leave a message after the beep.
If I do not return your call, you are one of the changes.”
