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Author "mikemoffit"

wrote in 1043: Heading Into The Library Stacks, Finder Secrets, Tasty Waves .

The waves I’m going to talk about here are a little bit different than the “tasty” waves Jeff Spicoli was looking for in Fast Times at Ridgemont High, but they’re still interesting and crucial to modern technology. First though, I need to distinguish what kind of waves I’m talking about. In previous articles, I talked about the electromagnetic spectrum. That spectrum itself is composed of waves too, and we describe electromagnetic radiation waves using wave terminology, such as frequency, amplitude and wavelength.

The waves I want to talk about here though are different. These waves are more accurately described as “electronic signals”. A very basic and simple example of this kind of wave is AC electricity. The voltage varies according to a perfect sine wave up and down, positive to negative. It has a frequency (in the US, 60Hz). It has an amplitude, which is 170V for 120VAC. So this signal is a wave, a sine wave, but it’s not really inherent. We can (and do) create AC electricity with all sorts of frequencies and amplitudes. These waves can also be highly irregular and change over time rapidly.

AC electricity is typically a sine wave because of the rotational methods by which most AC electricity is generated. Any time you have rotation and you’re stretching it over time you’re likely going to see something that resembles a sine wave somewhere along the line. The fact that our normal electricity comes in the form of AC isn’t wasted. We use the sine wave all the time. Induction motors for example use the rising and falling pulses of the wave to “kick” the motor armature into motion. The proper function of the motor depends on the sine wave input. We also use the frequency of the AC signal as a way for certain electronics to keep time.

Sine waves aren’t the only signals we create and use. In fact, while sine waves might be ubiquitous in industrial operations where AC electricity is being used directly, in the consumer world, the square wave dominates. A square wave looks exactly like you’d expect, a square. Unlike the sine wave which gradually increases over time, the square wave goes from one extreme to another almost instantly. Then it holds at some value before dropping back down again. Computers would not function without square waves. A square wave clock signal is like the ultimate orchestral conductor inside of every CPU. Without that signal, the 1s and 0s would be in chaos. Every time the square wave clock signal pulses, one step of the computational cycle can occur. When I built a computer from scratch in college, keeping the clock signal at a reasonable speed was critical.

Another huge use of square waves is in something called PWM (Pulse Width Modulation). PWM can be used to encode a message into a pulsing signal (like a clock signal) and then be transmitted via conventional means. This has applications in telecommunications, though it’s used less today with the advent of digital communications. PWM is also used in photovoltaic charging algorithms. When a battery is depleted, the pulses will be long in duration since the battery needs to be charged. As the battery becomes more charged, the pulses become shorter, thereby delivering less average current to the battery. PWM also has applications in just about any instance where precise motor control is required. Servo motors rely on PWM to function and normal, spinning motors can be adjusted for speed and torque with digital controllers. All CPU fans are controlled by this mechanism. Even my sewing machine relies on PWM. When I press on the foot pedal just a little bit, the motor only spins very slowly. Before PWM, this would’ve been accomplished using a variable resistor. A variable resistor would basically “burn off” excess power in the form of heat. This is wasteful and dangerous. If it got too hot, you could start a fire, or burn your foot. PWM simply sends shorter pulses of power to the motor causing it to spin more slowly. There’s no dangerous “burn off” of excess power. In fact, it’s only using the exact amount of power it needs.

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Square waves aren’t even the end of the story. There are triangle waves, and sawtooth waves and just about any other shape you can imagine (though they might not have any practical use). As an amateur composer of electronic music, the square, triangle and sawtooth waves are the bread and butter of synthesized sounds.

I’m not sure if I’ve changed Jeff Spicoli’s mind on these waves, but hopefully others have found this explanation of waves and signals to be interesting.

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wrote in Uncategorized .

Summer officially started this week. Has anyone checked with Mother Nature? Are we sure she got the memo? Seriously, sometimes I can’t tell where we are with the weather. I don’t really mind the hot weather at all, as long as I can do things like jump in a river, or ride my bike. The […]

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wrote in 1042: Lock Her Up In 10 Easy Steps, Fireworks Photos With Your iPhone, Hot and Cold .

Last week’s article on cooling got away from me a little bit. I had actually intended to discuss a very interesting, lesser known cooling method but it was necessary to lay the groundwork of how temperature works. That’ll make this article a bit shorter and to the point.

If you want to cool a large area, like a server room, a conventional air conditioner will always be your best bet. For the job, they are the most efficient. For the purposes of this article, we’re going to refer to air conditioners by a more technically accurate name: heat pumps. This is what air conditioners are actually doing. They are pumping heat from one area to another. Equipment in our server room generates heat, and the heat pump effectively absorbs that heat and pumps it outside. The heat in the server room heats up the cool decompressed gas and then this warmed, decompressed gas is directed outside, where its acquired heat will be dumped by a heat sink. Heat pumps can also work in reverse to warm an area. If our server room was an iguana habitat, a heat pump would take the small amount of heat present in cool, outside air, and compress the gas causing it to heat up, and then vent this heat, via a heat sink, into our iguana habitat.

Generally speaking, any cooling mechanism has a heating component to it. This type of heating/cooling all works by moving heat energy around. Other types of heating and cooling are called exothermic and endothermic chemical reactions, respectively. An exothermic reaction converts potential chemical energy into heat energy. An endothermic reaction requires more energy input (in the form of ambient heat) so the result is the reactants become cool because they’re absorbing the heat. The applications for this type of heating and cooling are limited, but specific. For example, chemical hand warmers that heat up when you break them, or ice packs that cool when you break them.

What if you had a small area, or even a small device that you needed to precisely cool, to within fractions of a degree? Chemical reactions and compressed gasses cannot be controlled precisely enough for this task. Enter the solid state Peltier effect. Any time you have two different types of metals joined together, heat energy can be generated or removed at the junction when electric current is passed through it. This will work with any two metals, but for high performance, useable cooling, Peltier devices normally use P N semiconductor junctions, and there are often dozens of them all packed into single wafer. When current is applied, one side of the wafer will become hot, and the other side will become cool. If left this way, the device can eventually self-consume. However, if you place heat sinks on both sides, the heat being “pumped” to one side of the wafer can be dumped. A heat sink on the cool side will allow for better cooling by providing more surface area for heat energy to pass through the device, to the hot side. Remember, heat energy is everywhere. What we call “cool” is just less heat. Unless “cool” is absolute zero, there’s still heat energy there.

Because these junctions can be manufactured at virtually any size, and current through them precisely controlled, they can create extremely precise temperatures. They have no moving parts, no refrigerant gas, compact and flexible shapes, can be used in almost any environment and have far, far longer service life than a refrigerant-based heat pump. Their disadvantages are that they are not very energy efficient in terms of cooling/heating performance vs a refrigerant-based system and they are unable to create large temperature differentials. A typical device will only be able to create a temperature difference of 70 degrees celsius between the hot and cool side.

Disadvantages aside, these Peltier coolers have many applications. Any small device (even USB-powered) that advertises cooling ability, will be a Peltier device. Small 12V coolers for vehicles often use Peltier elements. Spacecraft use them to reduce temperature differences on the spacecraft itself by pumping the heat generated by exposure to the sun to the shaded side of the craft. Some lasers use the coolers as part of the laser circuitry to maintain a precise temperature to stabilize the laser wavelength. Sometimes the coolers are even used as active (as opposed to passive) cooling devices for computer equipment.

I think this about wraps up most of the heating/cooling methods I’m aware of. If there are any that I’ve forgotten about, or anything else you’d like to know about, send me an email.

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wrote in Uncategorized .

Family: Mom (Heather) Dad (Andrew) Pets: Bella (bulldog) Hobbies/Interests: Mountain Biking, Skateboarding and snowboarding Favorite Books: N/A Favorite Bands: Dirty heads, 21 pilots Favorite TV: South park, Family guy, Arrow Favorite Movies: All the Rocky movies, Southpaw Favorite Food: Nachos or Pizza Favorite Drink: Cherry slushy Favorite Sports/Games: Mountain Biking Favorite Apple Products of All […]

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wrote in Uncategorized .

Family: I’m fresh out of high school, so I still live with my mom and dad as well as my 10 year old brother. My grandpa also lives above our garage, so he’s kind of an extension of our family. Pets: I’ve got two dogs, wheaten terriers, named Skoki and Addi. They’re insane, even in […]

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wrote in 977: Drone Etiquette, Using Filters In Gmail, The Blue Lights Blues .

So there you are. Hammering away at your keyboard, not breaking eye-contact with your monitor, your eyes observing intently the letters that manifest themselves against the white backdrop of your e-mail window with each click and clack of your fingertips. Before you realize it you have moved just a bit closer to your screen, your eyes feel strained and you have that little headache growing again.

These, my friends, are some of the side effects of prolonged exposure to artificial blue light. I’m sure many of us out there have the firsthand familiarity with the effects of the dreaded blue light, but those who might be a little unfamiliar let’s take a closer look.

We know light is made up of electromagnetic particles that travel in waves. These waves emit energy, and range in length and strength. The shorter the wavelength, the higher the energy. These varying wavelengths are each represented by a different color and they’re grouped into the following categories: gamma rays, x-rays, visible light, infrared light, and radio waves. Put all of these together and you have the electromagnetic spectrum, visible blue light is the neighbor to ultraviolet which as we know is quite harmful. Blue light has a very short wavelength and thus it contains a higher amount of energy.

This isn’t to say all forms of blue light are “bad”, by any means. In fact, quite the opposite. Let’s break down blue light in the forms of natural and artificial. Natural blue light is found virtually everywhere you look. It’s the reason the sky is blue, and it’s the reason our bodies tell us when it’s time to sleep. On a physiological level, blue light is quite beneficial for not only our physical wellbeing, but also our mental state. One could argue that it’s the reason some of us get bummed out when hit with a string of rainy days, and the same reason we feel joy when the sun comes back around again!

However, in this age of information, we’re subjected to artificial blue light on a daily basis. Devices such as your cell phone, your computer screen, your television, your tablet and energy efficient lightbulbs all mimic and imitate natural blue light. This fact is and of itself, is of course not inherently adverse to our health and wellbeing but overuse and prolonged overexposure to these devices can counteract the positive effects that natural blue light has on our bodies. Issues ranging from disruptions to sleep cycles, increased risk of depression, back and neck pain and of course permanent eye damage.

So what can we do to find the balance? Luckily for us all, more and more developers are taking steps to counter the adverse effects of artificial blue light. A new addition to macOS Sierra, 10.12.14, was Night Shift. When enabled, Night Shift will adjust colors of your display to the warmer, less intense colors on the spectrum when the sun goes down. Night Shift can also be found on your iOS devices, assuming you are updated to at least iOS 9.3. (Note: not all devices running the prerequisite iOS/OS are capable of running Night Shift) The shift in warmer colors has been shown to lessen the exposure and intensity of the artificial blue light and it’s also is more in-sync with our circadian rhythm, which governs the natural sleep cycle. Too much exposure to artificial blue light before heading off to bed has been shown to adversely effect our chances at getting a good night’s sleep, but reducing that blue light glow to a warmer color has yielded great results for me, personally.

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wrote in 977: Drone Etiquette, Using Filters In Gmail, The Blue Lights Blues .

A problem that many e-mail users have is receiving too many unwanted e-mails. I often receive automated e-mails for receipts or promotions that I don’t necessarily want to stop receiving, but are not important enough for me to want to receive a notification about them on my phone or e-mail client. For Gmail users, this problem can be easily solved by setting up a filter.

By creating a filter, you can ensure that e-mails are matching a specific pattern, like from a certain e-mail address or containing a certain phrase in the title or message are caught and filtered. They are automatically marked as read or sent to a specific locations. You create a filter by opening Settings from the Gmail website ( located in the gear icon), and navigating to “filters and blocked addresses” tab. From there you can click the “create a new filter” button to set the parameters for the filter.

I have dozens of filters set up on my Gmail accounts. Every few weeks or so, I look through my recently received e-mails to see if any could have been eliminated by setting a filter. The goal is to never receive an e-mail notification on my phone about an e-mail that I don’t want to reach. As you use more online services you will receive more e-mails that you might want to filter out.

Hopefully this quick tips helps you to keep your in box a bit less chaotic and allow you to focus on the e-mails you really want to see.

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