Friday, May 31, 2013

Building An AA Battery Pack For Charging USB Devices

There's lots of power packs out there to charge your USB devices. My problem with most of the
products I've seen is they are either expensive, or they don't allow you to replace the batteries. What I have been looking for is a power pack that I can replace the batteries when they get worn out. I'm not looking for something disposable.

So, my first project is a 4xAA battery pack that takes standard rechargeable AA batteries. These kind of batteries are cheap, easy to find, and have enough mojo to charge our devices like phones and tablets.
USB AA Battery Pack, Shown With Tenergy Ni-Mh Rechargeable Batteries
This particular battery pack is simply a housing which connects the four batteries in series. There's no electronics to regulate it or allow the power pack to be recharged from the same USB it outputs from, like other battery packs do. I would consider this really for a last ditch emergency way to charge your devices.

NOTE: Because this pack only gives power to the USB + and - certain devices that want to be connected to a computer (like my phone) will not charge. This does charge most devices in our house, though, like the wife's Kindle Fire (1st gen) and her HTC One.
USB AA Battery Pack Charging Bluetooth Headphones
The 4xAAA battery pack charging my bluetooth headphones

USB AA Battery Pack Voltage Reading Using Hacked USB Cable And Multimeter
Voltage shown using spliced USB cable

Saturday, May 18, 2013

Quickly Determine If Your Car's Charging System Is Working

This is the third time you've had to jump start your car in a week. Is the battery shot? Is it even holding a charge? Heck, is it even charging at all?

There are many factors that can affect your battery and the charge it holds. To get a grasp of the problem, first you want to narrow it down to just a few areas: battery, wiring and charging. Assuming you can start the car,  it's easy to quickly tell if your charging system is at least functioning on some level, which can help you rule that out.

In order to do this quick test, you will need an accurate method of measuring voltage. You can buy a cheap multimeter for $10 to $20. They are very handy to have, and versatile. But for this task, I personally use a little gadget that plugs into your car's cigarette lighter and tells you the voltage. They are more specialized, but run only about $4, making it a great investment in your vehicle's electrical health.

In a nutshell, if the voltage goes up when the engine starts, your car is charging. That's it. Obviously there are
other factors at play, but most of the time, if the voltage goes up, look elsewhere for your problem, like the battery itself, the wiring or maybe a parasitic drain. The readings below are for a Jeep which had a slow drain on the battery from an improperly wired stereo system.

Step 1 - Take Voltage Reading With The Engine Off

Your starting voltage ideally should be anywhere from 12.0 volts to 12.6 volts. Any accessories (lights, radio, etc.) will affect this reading and make it read a little lower. If you're sitting in the car, and there's no lights on and nothing obviously powered on, you should see a reading in the above range.

Determine if your car is charging: Starting Voltage
This reading is a little low, but still within range. 

Step 2 - Take Voltage Reading With The Engine On

You measured the voltage, and you started the car. Did the voltage go up? Then congratulations, you are charging. In general, you should be reading 14.0 to about 14.6 volts with the engine running. There are several factors that affect this number, but it's a good general range you should be looking for. If you see the reading in this range, then most likely you don't have a charging problem. I like to leave the engine running a few minutes to a) let the battery charge and b) make sure there are no fluctuations in the voltage.

Determine if your car is charging: Ending Voltage
This is a little low, but again, within range

Friday, May 10, 2013

Fun With DropBox

It started with the wife saying "hey, you should install DropBox." Why would I do that? I've been pushing files around on the Internet since the mid 1990s. There's all these great protocols: FTP, HTTP, NNTP and so forth.

However, after installing the software on my phone, tablet, laptop and desktoop, it turns out that "why use Dropbox?" has several good answers.

1. It's easy to use for non-technical people

Drag a file into one of your DropBox folders and it's immediately "pushed" out to everyone you share that folder with. They get an update telling them there's a new file there for them to look at. Any user familiar with basic computing concept like files will pick this up quickly. But of course, if you're such a Luddite that you don't even know what a file is, then DropBox won't be of much use to you.

2. It's easy to share files between different devices

Here's where I became a believer. There's lots of ways to move files around between all my devices. And most of my gadgets have some sort of removable media I can take out, copy files to and put back. If I need to move Gigabytes of data around, this is still the best method. But for a couple of files, or a family photo, it's a real drag.

For moving around those common, day to day files like a PDF document or family photo, DropBox makes it stupid simple. It can be a hassle to move files between different platforms like Windows and Android. For me, this takes all the pain out of moving files between my Windows laptop and Android phone, and I use it in this role daily. The device independence is my favorite part about the software.

3. It's Free

Some "free" software products claim to be free but just about the time it becomes indispensable, you find the catch, which usually involves you taking out your wallet. The best I can tell about DropBox, they want it to be so indispensable that you pay for more space.

They give you plenty of space to start with, and what they charge for space seems reasonable. But if you feed it the email addresses of your friends and family, they will give you more space as your friends join up. So, even though they charge for extra space, there's other ways of getting more for free. Personally, I think it's a pretty fair deal for free.

4. It Has Quests!

I'm a nerd. That's been established. One of the ways to get my attention (besides bacon or boobs) is to speak to me in the language of nerdy video games. So when I saw that DropBox offered "Quests" to get more space, it really got my attention, and I started completing them. This is really thinking outside the box.


As with any cloud service, there's more points of vulnerability to your privacy than if you were just exchanging files between friends and family directly. There's more risk to your files being intercepted by some third party. And there's definitely a risk that the company which holds your precious data could be hacked into or suffer a catastrophic failure, taking your important data with it. There's a lot that can go wrong.

Keeping all this in mind, most of the time the power and convenience of something like DropBox is going to be a fair compromise for the downsides. Basically, I just assume that anything I put in DropBox can be seen by the whole world, and if the company loses my files, well, I keep my own backups. So should you.

Windows Version

The Windows version consists of an icon on the Windows Tray portion of the task bar. It shows a little blue box, with a green check mark next to it if everything is in sync. When you click on the icon, the following window pops up.

DropBox for Windows - Main Window

Notice the little check mark that says "up to date" next to it, confirming that your files are synchronized. There's also a gear icon in the upper right hand corner for settings. Clicking on the settings icon gives you the following screen.

DropBox for Windows - Settings

Notice that it tells me how much of my space is used. It would be nice to see this on the main screen and not buried in the settings, but it's still a nice feature.

When a new file comes in from another device, or someone in your share group, you see the following notification balloon show up on your taskbar.

DropBox for Windows - Incoming Notification

What I did above was take a screen shot I want to use for this post on my Android tablet and moved it into my DropBox. A few seconds later, this notification popped up on my Windows laptop, which I'm writing this blog post on. DropBox is so awesome that I used to to help me write a post saying how awesome it is.

Android Version

Some popular applications make a half-assed attempt to provide for Android, as if Android support is an afterthought. That's not the case with DropBox. The Android version is every bit as good. It's fully integrated into the sharing mechanism of Android, meaning any tool bar that shows you icons for sharing your files will now show a little blue box icon.

DropBox for Android - DropBox Toolbar

The DropBox app itself is well thought out and very user friendly for Android. The main screen shows you the folders you have setup.

DropBox for Android - DropBox Folders

The settings are very user friendly as well. Maybe a little simplistic for my tastes, but this app is made for Grandma, too. All things considered, I like how they laid everything out.

DropBox for Android - Settings

DropBox for Android - Camera Settings

DropBox for Android - Favorites Settings


Occasionally the non-nerds in my life tell me about a new product or technology that makes me think "why wasn't I using this?" and this is one of those products. I realize there are other ones out there like GoogleDrive (which keeps changing identities), Microsoft's SkyDrive and a few others. I plan on checking those out, but I don't see how the whole process could be much smoother or more streamlined than this.

Saturday, May 4, 2013

Android Whip App From Big Bang Theory

I don't know if this is the exact app seen on the show, but it's called the "Big Bang Whip" and sounds just like the one we saw on that episode of Big Bang Theory. It's made by what appears to be a small shop, Studio 215. They don't seem to have a web site.

The great thing about this app is that there's no ads or nagware. It's free and all it does is make a whip sound. So far it's been great fun. It's a completely unproductive app which I highly recommend. I tried several other whip apps. Some had cool features like machine gun sounds, but they all had varying degrees of overbearing crap. This app is as minimalist as you can get. Just you and your whip.

Use is simple and intuitive: hold your phone like a whip and make a whipping motion.