Mike's Big Bad Battery Box

For those experimenters that are continually on the go, and need a mobile power source that could be lugged about. I offer you the Big Bad Battery Box. Original Article found here.

Finally getting around to filling the decade long need for power
A number of years ago I started toying with homemade VLF (Very Low Frequency) radio equipment. These radios covered a range of roughly 10Hz to around 10 KHz and to aid in reception with minimal noise, I needed to place myself and the equipment far away from man-made electrical interference. This meant going far away from the electrical grid for long periods of time.

As time marched on, it would seem that my need for portable power increased almost tenfold. I have many projects doing many different things, and I always seem to need power in places that scarcely offer it. (i.e. satellite/space station communication, VLF monitoring, geophone monitoring, watching satellite TV in the middle of nowhere, you get the picture). To facilitate all of this I needed a luggable and robust power source at a minimum of cost.

So what did I have on hand?
 Because this need for mobile power has continued for nearly a decade and a half, I happen to have a few parts lying about.

First up is the box. I picked this gem up from one of my regular haunts. It was basically just an empty box that at one time housed a Wheatstone bridge. The store clearly exploited my weakness for rugged wooden boxes.

I found a power supply that fit neatly into the box only one isle over from the box. The total cost of both items was somewhere around eight dollars in 1996.

Poking around a little further in my garage, I turned up a few lead acid batteries. These are two 4.5 Amp Hr 12 Volt lead acid batteries. I pulled these from a small electric scooter a few years ago and could not bring myself to dispose of them.

Ok, now that I have a bunch of parts, what the hell do I do with them?
Well first you want to assemble all the team members to see how things would be mounted and wired together.

The basic ideal was this. I wanted a box that contained, one variable power supply, both lead acid batteries, and a power connector. Each item would have its own power hook-ups. This way the box is multi-purpose. If near an outlet I can use the power supply, if not I can use the batteries in series or parallel, the power connector can be hooked up to either the batteries or the power supply. This configuration also allowed me to use the power supply to charge the batteries. Score one for me.

 Solving for the variable
The problem I now faced was how to make the power supply variable. I am sure there are many ways to do this and Lord knows the way I choose is not nearly as efficient as it should be. However I only was able to use what I had on hand and to make it work for me.

The picture below shows voltage regulators. They basically take a larger voltage and make a stable lower voltage, regardless of the load you place on them (Well, sort off).

The voltages I have on this unit are as follows 5, 8,12,15,18, and 20. The power supply provides around 21 volts. I wired these up to a 12 position selector switch.

In the second picture you can see everything all wired up. Be sure to make your lengths of wire consistent with how everything will be mounted in the box.

Once everything was soldered together it was time for a test. I checked each of the voltages and they all came out to be right on the nose.
 

Putting on a decent face.
Finally I had to make things look nice. I used an old piece of paneling from one of our daughter's walls as a face plate. I cut holes, sanding it down, and sprayed four coats of enamel on it.

Presenting the Big Bad Battery Box!
I am pleased. Now I just need enough time from all the events in my life to take advantage of my latitude this winter to see if I can catch some of the Northern Lights on my little receiver that will now have PORTABLE POWER!!!!

The Diabolical Phone Switch

Sick of teenagers abusing the use of your house phone? Well your prayers for a solution have been answered. I give to you the Diabolical Phone Switch. Original article available here.

 The Disclaimer
First let me say that I will not be held responsible for any of the dumb crap that may result from any ideas you may derive from the following text.

I am basically presenting a device that I created in a few nights worth of free time to cure a pesky problem I have been having with phone abuse from three teenage daughters.

Be aware that this device uses line voltages from an AC power outlet, and that proper care should be taken whenever line voltages are to be worked with. So be safe and don't be stupid!

But Why?
I like to think of myself as a reasonable person. I fully understand that teenagers like to use the phone, text message, and generally wallow in their own ultra-dramatic pubescence. Teenage girls are the worst for this. And having three of them REALLY makes things difficult when they all wish to use the house phone at once.

Despite the fact that there are 24 hours in a day, this still does not seem to be enough for teenagers who wish to blabber all day and night.

Because of this, I find myself threatening to disconnect the phone at a predetermined time of the evening just so I can get some sleep. Furthermore before my nightly slumber I have to either walk around and collect all the phones or unplug the main line.

This is no joke they will literally stay up all night on a school night talking non-sense.

To remedy this and save some sanity I decided that some automation might take care of this problem. This way I don't have to lift a finger to insure that the phone goes off at a certain time of night. 

What I need it to do

Basically I need a machine that I can put into the main phone line, which will turn off the phone as per a schedule that I can control. I will also need it to default itself to enable the phone line if power is lost in case of emergency.

To accomplish this I will use a lamp/Christmas light timer that has the ability to be programmed on a weekly basis.

When triggered the timer will enable a 12-volt wall wart (Transformer), enabling a relay, which is normally closed. This breaks the contact in the line disabling the phone. The timer will also remove power to the transformer to release the relay and re-enable the phone.

The Pieces and Parts of it all
Okay, so this is where you need to put on your thinking cap.

Going through the parts required you want to make sure that you choose a timer that will suit your needs. I had one laying about that allowed me to program a weeks worth of scheduling.

As for the wall transformer and relay. You want to make sure to match the voltage of the transformer to something the relay can handle. The smaller the voltage and current consumption of the relay the better. Also the relay will need to be able to switch at least two wires. Each phone line is a pair of wires. Finally you'll need a pair of phone jacks and a box to mount everything in. 
 
Start soldering it all together

Be careful and double check everything that you are soldering together. Here you can see the relay being soldered.

Also I needed another wall transformer since the other one didn't produce the correct voltage/current that was needed for the relay.

In the back you can see the phone jacks. We will be utilizing the red and green wires on both the jacks. When wiring to the relay make sure that green connects to green and red connects to red.

Getting it together and testing
 Here we see everything soldered together, and ready to be tested. The timer that I have allows you to trigger it manually. I used a multi-meter set to check for continuity to insure the relay was working properly.

Once everything checked out, it was time to mount into a box.

 Scary isn't it?
Looks more like a time bomb then a device to cut off a phone-line doesn't it? It's packed into the box a little tight but I had to use what was on-hand. I kept the components secured to the box using Velcro on the bottom of it and then put Velcro on each component. It's not fancy but it seems to work.
I also cut a few holes in the lid for the phone jacks and the A/C line cord. Once the timer is programmed I tape the lid on, plug in the phones and wait for the cry's of pubescent angst. My days of yelling to get off the phone at a reasonable time are FINALLY over.

Tis the season for Ground Radio

Well I had thought about it, I have planned it, and now I have finally got started in my experiments in ground radio.

Ground radio is simply like any other form of radio with the exception of the antenna system. In this method of receiving and in some cases transmitting signals, a ground rod is used as the antenna. For more information on the benefits and strange occurrences in the ground radio field please visit this link

Aside from some of the more corny aspects that the link has to offer I still have a lot of faith in what a ground radio system can provide.

 

The Setup

Below is a picture of my meager setup.

This is my ground radio electrode. It’s basically just a 5 foot copper pipe 3/4 inch in diameter. Every 6 inches I drilled a hole through the pipe. Once driven into the ground I charge the electrode by pouring brine solution into the pipe. The solution leeches out of the pipe into the surrounding soil. Once it looks like the liquid has leeched out completely I then pack the pipe with rock salt to keep it charged.

This is the radio receiver I hook up to the ground electrode. I believe this is a Rycom 6010 Selective Voltmeter. Basically it’s a voltmeter that monitors AC currents. The cool thing about this meter is that it is tunable with a tight 250hz filter and can monitor AM and BOTH sidebands.

If you look closely you’ll note that the meter portion of the unit is modified. I had to put my own meter into the unit since it came from EBay with a busted meter. I tap the wires going to the meter and use them to interface with a PC.

 

Next I take the wires coming from the meter tap and hook them up to a data logging voltmeter that is serially connected to my computer. If you look at the screen you’ll see the results of about 12 hours worth of monitoring.

 

The Experiment
The experiment at this stage consist mainly of monitoring a signal over a 24 hour period, logging the results on the PC and then having the data produce a graph that shows signal strength over time.

For this I needed a signal that is not only constantly on, but will also change overtime. A good candidate for this is a Navy Submarine Mega Transmitter in Cutler Maine. This transmitter is part of a network of very low frequency transmitters that broadcast a 50 baud signal to all the Trident Submarines all over the globe. As a side note I have come to find it a pointless venture to try and decrypt this 50 baud signal.

 

In addition to the transmitter broadcasting on the order of a million watts, the antenna system is also designed to penetrate through earth and water to get its signal to the sub.

Also because the signal is 24 KHz, its wavelength is roughly the distance from the ground to the ionized layer of atmosphere that is affected by the sun. So here we have a signal that can both travel through the Earth & water yet have its signal strength affected by the sun.

 

The Results
When I first hooked the receiver up to the ground electrode I was surprised at the intense signal strength and low noise ratio that the system produced. I was picking up things that I could NEVER pick up with an antenna above the ground. Furthermore, I did not have to have a tuning network setup to reject unwanted noise.

 

The first attempt to monitor a 24 hour period’s worth of data failed because the video card in my ancient PC gave out. After playing with the software a bit I managed to get it installed on my laptop and succeeded in my monitoring efforts.

 

Below is the graph I got from the monitoring I did two days ago.

Ok, the X-Axis is obviously time over a 24 hour period. The Y-Axis is the signal strength dictated by the meter in milli-volts.

 

If you look around 6:12 AM you’ll see that the sharp drop in the graph represents the sun rise. As the sun rises the solar radiation starts to hit the atmosphere and it begins to ionize. This ionized layer causes the signal strength to drop.

 

You can see after the sharp drop in signal strength that there is a small burp that occurs after this. This has always happened in all my monitoring and I’m not really sure WHY it happens.

 

Moving on you can see that between 10:30AM and Noon there are two sharp spikes in the graph. These are either small solar flare, or some sort of gamma ray burst. Two years ago when I did similar monitoring there were many events like this that lasts many times longer since we were at the peak in our solar cycle.

 

Finally around 5:40 PM we see the signal strength jump up again as the sun sets.

 

Lessons Learned
Well it’s hard to tell, since I have done this sort of thing before.

 

This experiment was basically set up to insure that my equipment is in working order.

 

And the results are, it worked perfectly for my needs to move on to other ground radio experiments.

Next I plan to use more then one ground electrode and to place a big coil and a tuning network in the system.