Sunday, August 28, 2011

Pen Ink Replacement Hack

If you have ever had to buy ink refills for a pen, you know that they can be expensive and finding refills for unique pens can be nearly impossible. But fortunately many of these pens can be refilled using the ink reservoir from cheap disposable pens that you have lying around the house. 

There are three main styles of refillable pens. There are non-retractable pens. There are retractable pens that extend and retract with a push button and there are retractable pens that extend and retract by twisting the base of the pen.  Before you do anything check to make sure that they refillable pen and the disposable pen have tips that are the same diameter. Otherwise this hack will not work. If you have a non-retractable pen, you may be able to replace by simply putting in the new reservoir from your disposable pen. You may have to trim off the spring tabs if it doesn’t fit.  If you are refilling a pen that extends and retracts by twisting the base, cut the ink reservoir from the disposable pen to the same length as the original tube. Then just fit the plastic end cap on the new reservoir and reassemble the pen. Again you may have to trim the spring tabs if it doesn’t fit back together. If you are refilling a pushbutton pen, first remove the plastic end cap from the ink reservoir and cut the ink reservoir from the disposable pen to the same length as the original assembly minus the length of the end cap. When reassembling the pen simply place the end cap back into the pen where it would normally sit and then place the new ink reservoir on top of it. This will allow the normal push button action to work. This hack should work for most medium tip ball point pens. But keep in mind that there are slight variations between brands and styles so it might not work 100% of the time.

Ballpoint Pen/Mechanical Pencil Hack

It’s always useful to have a pen or pencil nearby in case you need to write something down. Unfortunately, they aren’t always convenient to carry around with you. For instance, if you have shallow pockets, a standard pen or pencil is just too long. In this hack, I am going to show you a really simple way to take a ballpoint pen or a mechanical pencil and cut them to a more convenient size.

Pens that work best for this hack are the standard BIC ballpoint pens or anything in the same style. First disassemble the pen by twisting off the end cap (click/button end) and removing all the internal parts. Then, using a sharp knife cut the outer housing to the desired length. This will crimp in the edges of the plastic tube. So use another pen (or anything with a similar shape) to flare out the cut end. This will make it easier to fit the end cap back on. Then use the part of the tubing that you cut off to measure where to cut the ink reservoir. It is important that you cut both the outer tube and the ink reservoir by the same length. If you cut the ink reservoir below the ink line, clean off any ink from the end of the reservoir, and everywhere else. The ink in these pens is highly viscous so you shouldn’t have to worry about it spilling after you clean off the end. Then just reassemble your pen. 

This hack can also be done with mechanical pencils but with a few limitations. The pencil must be a style where the eraser end can be removed. PaperMate pencils work best for this because they can be completely disassembled. Mechanical pencils tend to be made from brittle plastic. So you will want to use a fine toothed saw to cut the outer housing. I had good luck using a scroll saw. Just be careful and go slowly, this plastic cracks easily. You are also limited in how short you can make a pencil without altering the lead inserts.
Since this hack works best with cheap pens and pencils you can make a variety of sizes for whatever application you want.

Saturday, August 27, 2011

12 Volt Battery Hack

Another popular battery hack involves the A23 12 volt battery. These are often hacked as a cheap source for button cell batteries. To do this hack, take a pair of needle nose pliers and pry up the top corner of the seam in the metal casing. Then peel away the metal casing and remove the cardboard insulation. Inside will be eight LR932 button cell batteries. These button cells are a fairly popular size and can be used to power a wide variety of small electronics. The main advantage of this hack is that these button cells are usually much cheaper than buying them from the store directly. This is really useful because button cell batteries are used in a lot of hacking projects. For example they are great for making LED "Throwies" But my favorite application is making miniature battery packs. If you ever want to miniaturize a circuit project, the first thing to do is use smaller batteries. Here is a quick example showing how you can make a miniature 9 volt battery.

First make a stack of 6 cells and wrap them in tape to hold them together. Then cut a piece of heat shrink tubing that is about an inch longer than the batteries. Insert them into the tubing and shrink the tubing starting at the ends alternating from one side to the other and back. This will squeeze the batteries tightly together and help make a good connection. Use a sharp knife to trim off any excess tubing so that the tubing is flush with the end of the batteries. Use a voltmeter to check the voltage. Fully charged this battery pack should read out at a little over nine volts. Now you have a 9 volt battery that is less then ¼ the size of a standard 9 volt. This can go a long way in making miniature circuits. The only down side is that this battery pack will only have capacity of about 55mAh instead of the 565mAh in a standard 9 volt battery.

9 Volt Battery Hack

The first hack that I am going to present is the classic 9 volt battery hack. This hack has been done over and over again. But I am going to try to be a little more thorough and present some new information.

First, let’s start with a little background information. There are two main styles of construction for 9 volt batteries. The first and most popular style is made up of 6 AAAA batteries. Batteries in this style include Duracell, Energizer, DieHard, RadioShack and many more. An example of this is shown on the right side of the picture below. The second main construction style is a stack of short fat rectangular cells in a clear plastic case. The middle battery in the picture below is a typical Rayovac 9 volt and the battery on the left is typical of EverReady, as well as many generic brands. Unfortunately, this style of battery is difficult to safely disassemble. So I am just going to talk about how to hack the first style constructed from AAAA’s.
To open a 9V battery, Find the seam in the metal case and pry up the edge with a screwdriver. Then take a pair of needle nose pliers and peel away the metal. You should just be able to roll up the metal like a sardine can. Then pull off the connector cap to reveal your 6 AAAA batteries. They should just come right out. The only exception is Duracell who wraps their batteries in an extra layer of plastic and connects the batteries directly together with small metal strips. This can be really useful if you want to make a freeform battery pack but not if you just want some AAAA’s. In my opinion, the best brand for extracting AAAA's is Energizer.

AAAA’s are mostly useful for making miniature battery packs or substituting for AAA’s in an emergency. You can do this kind of substitution with any size battery. You just need to find a way to fill in the gaps. You can use coins, nuts, washers or just scrap metal to bridge the electrical connection. To ensure that they fit in the battery slot, the easiest thing to do is wrap them in a few layers of tape. Just keep in mind that they won’t last nearly as long as the larger battery.