Rusty Nail Workshop Projects

The Solar Powered Cell Phone Experiment

Sun, 21 Feb 2010 15:31:00 -0600

Question: Is it possible to power a cell phone (specifically, my iPhone 3G) with just solar power without the need for huge, permanent solar panels?

Background Research: In order to determine if this was possible, I needed to do some research. First, I tried to find out if anyone had attempted this before. A quick web search told me that a few people had powered their cell phones while camping using some portable solar panels, but nobody had apparently attempted to do what I was hoping to do.

My next step was to determine what solar panels (or solar cells) were available. Very quickly I determined that there are two types of solar panels: (1) those with an integrated Lithium battery pack which the solar cells charge; and (2) those without a battery pack which only charge your phone when both your phone and the solar cells were in the sun. I chose the solar panels with the battery pack since this meant I could leave the solar cells in my car all day while I worked, and charge my cell phone at night.

A quick bit of research found the following solar cells, all of which were suitable for my purpose:
‣ Solio Mag
‣ SolarMio 31
‣ Brunton SolarRolls

I initially chose the SolarMio 31 since it offered better charging in low light (cloudy) conditions, but it did not have as large of a battery pack as the Solio Mag. The SolarMio was also less expensive than the Solio Mag. The Brunton SolarRolls did not have an integrated battery, so those were out of the question. However, when I arrived at my local REI store, I found they were offering a Brunton Freedom charger. This charger used a Lithium battery and was half the price of the SolarMio! The battery is a 2,200 mAh battery, which is more than enough to charge my iPhone, and well over double what is offered with the SolarMio (900 mAh). The photo to the left is the Brunton Freedom.

Hypothesis: If I try to use only a portable solar cell or panel, I should be able to power my iPhone 3G without the need for any supplemental power from an outlet or car charger.

Experiment: I plan to hang my Brunton Freedom in my car window every day while I am at work (roughly 9 a.m. to 5 p.m.) facing South. I will then use the Freedom to charge my iPhone. I will not use any other supplemental power.

Data Collection: I placed the cell phone in my car window while I was at work, starting on Monday, February 22, 2010. I left it there until I left for home each day.

Analysis: The Brunton Freedom was able to fully charge my cell phone on Monday night. This was likely due to the full battery in the Brunton device, since I had pre-charged it before Monday using a wall charger.

Monday, February 22, 2010

On Tuesday evening, the Brunton solar panel battery was only able to charge my device to 80%. This was probably due to the fact that the device only had 50-75% of the battery charge remaining, which was not sufficient to fully recharge my depleted cell phone battery. Unfortunately, it was mostly cloudy or overcast on Tuesday, so the Brunton device was not able to fully recharge.

Tuesday, February 23, 2010

After work on Wednesday, the third day of the experiment, I had to stop the test. My cell phone battery was at 25%, and the solar cell battery did not have enough of a charge to charge my cell phone at all. What was especially disappointing was that the solar cell on the Brunton Freedom was insufficient to even charge the internal battery over 25% after the device was left in the full, bright sun for eight hours. I would have expected it to be at least half full, but it wasn’t.

In case anyone is wondering, I have included the graphs showing the solar intensity each day. Except for a few tiny dips, the sun was shining clearly the entire day on Wednesday.

Wednesday, February 24, 2010

I have subsequently found out that Brunton offers the same model solar panel with two 100 mA solar cells, which would presumably charge the internal battery twice as fast. Even with this second panel, I have my doubts that it would have charged the internal battery sufficiently to fully charge my cell phone.

Conclusion: It is not possible to charge an iPhone (3G) with a small, portable solar panel as the only source of power for the phone. Supplemental power will be necessary or the phone use must be extremely limited.

Finally, if you plan to buy a Brunton Freedom, make sure you understand it’s limitations. If I had a week to leave it in the sun, this might have been a different story.

Energy Conservation

Fri, 12 Feb 2010 19:15:37 -0600

Unless you have been living under a rock, you can’t help but notice that lately everyone seems to be eager to conserve or reduce their energy consumption and increase the efficiency of the items they purchase. Not only is it the popular thing to do, most consumers expect substantial savings by spending less on the energy needed to power our lives. I suspect, however, that very few people actually measure how much energy they are saving.

In fact, there is an effect called the Jevons Paradox that states that as consumers save energy, this naturally results in the cost of energy becoming cheaper. This then causes economic growth and consumers use even more energy than before! Still, the argument exists that you cannot understand or begin to control your energy consumption until you actually examine the data. Knowing your usage will lead to, hopefully, more responsible choices going forward.

To begin to understand my energy consumption, I started by collecting my historical energy usage from old electric bills. I even contacted the local electric company to ask for copies of missing bills so I could fill out my data.

I also did the same thing for my natural gas usage. Everything I collected went into an Excel document for further analysis.

This allowed me to generate some graphs showing the electricity and natural gas usage as a function of the average monthly temperature.

I used the average monthly temperature as the X-axis since a monthly plot does not take into account one month which happens to be an above or below average temperature for that year.

When the furnace needed to be replaced, I added a heat pump to the setup. The heat pump was sold to me on the basis that the cost per million BTUs was about one-third as much as a natural gas furnace. Sounds like energy efficiency, right? Now that it has been running for a while, how do I prove that I’m saving money? I know that a heat pump uses more electricity, so that cost should have gone up.

The month with the heat pump is on the left above. The right image shows a typical month with gas heat from two years prior. Notice the two numbers above were taken from two different months with the same average temperature. This is important to see if my usage at a given temperature has gone up or down.

I also know that using a heat pump means I’m not burning as much (or any) natural gas, so that cost should have gone down.

The image on the above left is the natural gas used with heat provided by the heat pump. The image on the right is a typical month with gas heat about two years prior. If I combine the two numbers and compare it to historical data, I should be paying less. When I compared the total invoice cost of operating a heat pump for heat versus a natural gas furnace for heat, I found that I was saving $14.15 last month ((New electric bill + New natural gas bill) – (Old electric bill + Old natural gas bill)). So the installation of a heat pump has actually started to pay off! Granted, this is only one month of data and a little lower than I expected, but I fully expect this savings trend to continue. At least now I know how to measure it. Knowledge is power!

Jawa Eyes

Sat, 12 Dec 2009 16:35:36 -0600

For Halloween this year, my boys decided they wanted to be a Jawa from Star Wars. One of the requirements was that they have glowing eyes. Not just any glowing eyes, but orange glowing eyes. This is how I created some realistic Jawa eyes with just a few dollars of materials.

First, to get the orange glow, I purchased some high intensity orange LEDs (part number 404-1097-ND) from Digi-Key. They were only $0.71 each. I also purchased a 9-volt battery clip (part number BS12I-HD-24AWG-ND) for $0.33. To control the current going to the LEDs, I purchased a 500 ohm potentiometer (part number 3386W-501LF-ND) for $1.29.

I wired everything up on a breadboard to test out the LEDs. (Ignore the extra components on this breadboard, they were from a different project).

I then purchased a pack of cheap ping-pong balls from Amazon.com. I took a ball, cut it in half with a razor blade, and held it over the LED.

The light was too focused. So I ended up trying a bunch of material, and settled on some batting (fluffy white quilting stuff that comes in sheets) from my wife’s sewing supplies. I folded over a few layers over and tucked them inside the ping-pong ball eye, securing them with some hot glue.

My wife purchased some eye masks from a craft store (in black) and had some black fabric that we could use to cover the faces of the boys. I used some wire I had from a previous project, and wired up the LEDs according to the schematic provided by the LED Wizard web site.

I cut out eye holes in the fabric that I glued to the eye mask so the boys could see, and I mounted the LED covered ping-pong balls halves just below the eye holes.

When everything was done, we had a great Jawa costume. Here is a photo taken during the daytime, and then one at night.

And here is a photo taken with the lights on at night.

Glow In The Dark Stars

Thu, 24 Sep 2009 20:53:44 -0500

When I was younger, I would lay in bed and imagine I could see the stars through my ceiling. My dream became a reality when I turned 14 years old. Well, almost a reality. While shopping at a local craft store, most likely with my parents, I found a bottle of glow-in-the-dark paint. Being a mischievous child, I immediately painted random dots on my ceiling, thus creating my window to the heavens above.

When my parents eventually sold our house, long after I had moved out, they found that it took three layers of white paint to completely cover the glowing stars I had painted. My first thought was, why cover them? Surely a new buyer would want a room with a view of the night sky. Apparently my parents did not share my view on this topic.

Fast forward a few decades, and I stumbled across a web site called Glow Inc. They happen to sell glow-in-the-dark paint containing strontium aluminate pigment. The claims made on this site indicate this paint is 25 times stronger than the hobby store paint I used as a kid. Cool! A $10 order later, and I had a new project on my hands.

Of course, I decided I would paint our bedroom so I could lay on my bed at night and look up at my handiwork. To make it as realistic as I could this time, I downloaded a free program called Stellarium and printed a screen shot of the night sky. I then drew a 1” x 1” grid over this printout.

Now I simply needed to make a 1’ x 1’ grid on my bedroom ceiling. Since we have a popcorn ceiling, I wasn’t afraid of making small holes in the ceiling, which probably wouldn’t be visible once the pins were removed. So I grabbed my wife’s sewing pins and began to mark off one foot intervals all around the room. Using her brown sewing thread (shhh!), I would the thread back and forth across the room, tying it on the first and last pins. Voila! A perfect suspended grid on my ceiling.

Using my night sky printout as a guide, I began to place dots of V10 glow-in-the-dark paint on my ceiling one square at a time. This wasn’t very easy to do, since my neck lasted about five minutes before it felt like my head was going to fall off. That, and painting white paint on a white ceiling in the daytime means I couldn’t tell which dots I had painted from my printout. I worked down each row, running out of paint after the first five rows. I should have ordered more than 1/2 ounce of paint.

Once it was dark, I was able to view my progress and the effectiveness of the V10 paint. It quickly became apparent that I used a LOT of paint for each dot. Most dots were about the size of this letter “O” - which is too much. The should be the size of this period “.” instead. I’m waiting for more paint, but for now, here is what the stars look like in a dark room.

What really concerned me is that at night, while looking up at the stars, I started to see them move. It felt like an optical illusion. The harder I tried to keep them still, my mind saw them moving. It reminded me of the optical illusion on the right. Notice how the dots seem to move by themselves.

Update (12/12/09): After a few months of looking at the stars, I have grown attached to them and they no longer make me feel like I’m moving. I still haven’t finished the other half of the room, but that’s just for lack of motivation. I’ll finish it eventually. Overall, I consider this project a success.

Project Paracord

Tue, 25 Aug 2009 20:24:24 -0500

About six months ago, I was looking for a good EDC (Every Day Carry) pocket knife. Every gentleman should have a pocket knife for those random times when something suddenly needs to be cut. For example, a thread from a piece of clothing. Eventually I settled on a Spyderco Spin Etched Stainless Steel Plain Edge Knife. The knife alone looked a little naked, so I found a web site that offered paracord fobs for pocket knives. I purchased one, which complemented the knife very well. I forgot where I purchased it from, but it was only seven dollars. For those confused as to what paracord is, it is essentially 4-5 mm parachute cord, containing seven individual strands of rope inside a sheath. A hundred feet of paracord costs about seven dollars.

Fast forward six months, and I suddenly had the urge to make my own paracord items. The internet is littered with do-it-yourself instructions and videos on how to make a survival bracelet, belt, dog collar, you name it. First, I picked up some fake paracord from REI. After messing around with that for a week, I finally purchased some real paracord from Supply Captain. I started with HobbitAssasin08’s video on how to create a bracelet with a cobra knot. He did a good job, and my first paracord item turned out nicely.

I then went on to try a few other paracord items, such as zipper pulls, key chains, a camera strap/lanyard, and even a few cool knots (for the fun of it).

The camera case fob below was made with the (fake) REI paracord.

The key chain below was made using a cobra stitch with a twist. The twist is just making the cobra stitch on the same side each time, which naturally causes the key chain to twist one direction.

Finally, I had purchased a plastic buckle at REI when I first purchased my fake paracord. The buckle cost seventy-five cents, and was in the section with the backpacks and straps. I used this to make a bracelet. I tried something different by using a double tatted chain or seesaw knot. It may also be called a zigzag knot, which is a simple pattern of half hitches on each side.

Finally, for anyone looking to create something from paracord, I strongly recommend checking out Stormdrane’s blog. He’s certainly got some experience under his (paracord) belt!

1963 Mercury Comet Custom Convertible

Thu, 2 Jul 2009 08:16:55 -0500

Over the past weekend, we picked up a 1963 Mercury Comet. Not just any Mercury Comet, but a custom convertible with a 170 engine. The car is mostly original, with only about 76,000 miles on the odometer. This will make a great project car. It is our hope that we can fully restore this car to original condition, yet make it completely able to be used as a daily driver.

One of the first problems I encountered when researching the car was obtaining a shop manual. You’d think Ford (Mercury) would produce a shop manual for each car, for each model year. Unfortunately, this is not true. After about five hours of research, I found that I need the following manuals to work on this car. All were found at Faxon Auto Literature.

• 1960-1962 Ford Falcon Shop Manual
• 1961 Mercury Comet Shop Manual
• 1963 Falcon & 1962/1963 Comet Shop Manual Supplement

So instead of a single $40 book, I’m buying almost $90 worth of books to diagnose problems with this car. Ouch. There are manuals available online for free, but printing them out is not possible. Using a web site in the garage isn’t the most convenient option.

7/19/09 - The car has been in the shop to have some transmission work done. Of course, there is no direct “drop-in” transmission for this vehicle. So, it will be rebuilt using a mixture of new and old replacement parts. Nobody said this was going to be easy.

I’ll update this page as our restoration work continues.

Helmet Camera

Fri, 29 May 2009 20:18:39 -0500

With the miniaturization of camera components, including the increasing size of flash storage space in such small packages, the shrinking of cameras was inevitable. With the decrease in size, the ability to record just about every aspect of one’s life is also possible. Plus, the cameras can go where it was previously impossible. This makes it attractive to record those moments where we really feel alive - when the adrenaline is rushing. Thus, enter the world of the helmet cam(era).

After conducting a bit of research on which helmet camera offered the best quality video, the smallest size package, and the most robust features and camera body, I selected the VIO POV 1.5. It’s expensive, but I hope to recover some of the cost when I sell it later to fund another project.

The camera is the size of a lipstick case, and is connected to a solid state recording device which is about the size of a TV remote control. The recording device uses SD cards to record, and also includes a small LCD screen so you can make sure the camera is appropriately aligned for the recording. It also presents several options via menus, selectable via several small buttons below the LCD screen. A small remote control can be used to start and stop the recording without access to the recording device. The device is waterproof to three feet, and appears very solid and rugged. Perfect qualities for a helmet camera.

So, what is the first thing anyone does with a new toy? Why, test it out, of course! I strapped the helmet camera to the front of an ATV and started out along the road. The camera recorded perfectly in DVD quality. I’ve included a sample video below from my ride, but resized to be manageable over the internet. The actual video is much larger and better quality.

What would I change about the camera? First, I’d shrink the recording device. It needs to be about half as thick and about half as tall. Second, the ports on the bottom need an easier access cover, but the cover does its job effectively. Third, I’d make it waterproof to about 30 feet. That would cover SCUBA diving in most lakes around here.

I have a few more videos I would like to try. I plan to use it to see inside walls when running cable, to help see inside my car’s engine, and to look down the hole in the ice when I’m ice fishing. Either that, or I’ll see what it’s like to be a minnow in the minnow bucket!

Do-It-Yourself Blu-Ray Laser Pointer (Part 2)

Thu, 12 Mar 2009 16:18:55 -0500

Everything I had read thus far told me that I needed a circuit which supplied a constant current to the laser diode. It would have been easier if I could have just connected the laser diode to my DC power supply and adjusted the voltage, but that would have been too easy.

By the way, this is part 2 of a two part series on this project. If you missed part 1, you can review it here.

I’m not very good at designing my own electronic circuits, so I thought I’d cruise the internet to see if someone had put one together already. Sure enough, I found a circuit Joey Hagedorn’s web site. Apparently he tried something similar to this project, but with a different laser pointer.

The circuit I ended up using is shown above. I ordered all of the parts from Digikey.com, which came to $4.60, which included $2.02 in postage (U.S. Postal Mail). I love this company, they have what I need and they shipped the parts out fast!

Here is what I purchased for the circuit:
• One LM317TFS-ND IC Regulator (adjustable)
• One 47 uF capacitor (P802-ND)
• One 10 uF capacitor (P807-ND)
• One 0.1 uF capacitor (P820-ND)
• One 100 Ohm potentiometer (3309W-101-ND)
• One 15 Ohm resistor (CMF15.0HFCT-ND)
• One diode (1N4002GOS-ND)

I wired everything up on a breadboard that I had from a previous project, and I even set up the circuit to match the schematic shown above.

As you can see from the photo, I used a common red LED I had to test the operation of the circuit. Sure enough, the LED lit up (although it was very dim), and I even had my multimeter connected to measure the current in the circuit. The LED would draw anywhere from 5-10 mA from my circuit. I adjusted the potentiometer to somewhere in the middle and increased the voltage from my DC power supply to 8 volts. No change in the LED brightness, which means my laser diode would be safe at 8 volts DC.

I then tried to find out from Sam’s Laser FAQ site which pins on my laser diode were supposed to be used for each connection. The site is a good site, but has too much information, and I just wanted to get started. I made a guess and wrote it down.

Next, I put on some laser safety goggles that I had previously purchased (for another project) just in case this laser diode was bright enough to damage my eyes. I also set up my video camera to make sure I could see the beam if it emitted infrared light instead of visible light. I made a guess for my connections and connected the Blu-Ray diode to my circuit.

Nothing happened. Maybe I had a loose wire? Nope. I also noticed that my meter wasn’t detecting any current. I tested the circuit again with the red LED. Yes, it worked just fine. I then began the process that any experimenter tries when something doesn’t work right. I started connecting the positive and negative wires to any of the three leads I could, hoping that I just had my laser diode pins identified incorrect. After about five different combinations, I found one that emitted blue light. It worked!

I was a little surprised to see that the blue light being emitted wasn’t focused into a reasonable beam. I guess I should have expected this, but I was surprised none the less. The blue color doesn’t photograph well, but you get the picture. The real color isn’t that much more impressive, so you’re not missing much.

I grabbed the lens assembly I had saved from the Sharp Blu-Ray player and put it in front of the beam. Neither lens on this assembly focused the beam down like I wanted, so I found another lens I had lying around. That didn’t work either. I’m going to have to work a little harder to figure out how to focus this beam down, but at least I have a working blue laser!

At the end, I noticed that my multimeter was measuring 25 mA of current. I adjusted the potentiometer upwards and the meter went up to 30 mA. I think this is a safe level for continuous operation, as explained by others who tried this same experiment. A video of the diode in operation is included below.

Watch for future updates here as I finish the construction and package this circuit into a working blue laser pointer!

Do-It-Yourself Blu-Ray Laser Pointer (Part 1)

Sat, 7 Mar 2009 12:51:56 -0600

About six months ago, I purchased a Sharp Aquos BDHP20 Blu-Ray player to watch movies I rent via Netflix. The DVD player worked perfectly for several months, enabling me to watch all sorts of movies in high definition. Life was good.

Then one day, a disc refused to load. I figured it had a scratch, and I tried other Blu-Ray discs. None would load. I found a firmware update, and updated the firmware. No go. The player still wouldn’t read the discs. It played DVDs just fine, but not Blu-Ray discs. I eventually got frustrated enough to purchase a new Blu-Ray player, figuring I’d dissect the old player and extract the Blu-Ray laser diode.

Some history is in order here. I built my first laser pointer in 1991, from a schematic provided by a Popular Electronics magazine. The red laser diode cost me $150, direct from Toshiba. I still have it, and the laser pointer, although big, works perfectly.

With my two boys, I took the cover off of the Blu-Ray player and started to track down the laser diode assembly. Very quickly, I found a box that looked like an external DVD player that you might find for your computer.

I removed the assembly that accepted the discs simply by unscrewing a few screws and pulling out a few cables. This process was very similar to removing a CD drive from a desktop computer. In fact, some of the connectors looked exactly the same.

Disassembling this drive took a little more work since the cover had some metal tabs that needed to be unbent before the cover would come off. I cut my thumb in the process, so please be careful if you try this at home.

The photo above shows the inside of the drive assembly. The black circle in the middle of the above photo is the part that spins the disc in the drive. The entire center assembly moves forward and backward on a threaded rod so the laser can read from the center to the outer edge of the disc.

After a few minutes, I found the screws that allowed me to remove the laser assembly. You can also see the threaded rod better in the above photo. I just cut the ribbon connectors and pulled this out since I’m not going to be using the connectors anyway. I’m after the laser diode itself.

I finally removed the mechanical pieces and pulled out the optical assembly (as shown above). This piece easily fits in the palm of your hand, and houses what appears to be two lenses, several tiny glass mirrors, and some tiny electronics. The lenses are on a moveable section held in place by very fine wires. I originally thought this was what I wanted to extract. I was wrong, as I later found out. There are small coils of wire and strong magnets under the lenses that are used to focus the light beam on the different layers on each disc. The laser diode is actually the part in the top right in the above photo. It looks like a small gray box, the gray part is the heat sink and should also be kept.

Here is another view of the laser assembly. The diode is on the bottom right, and the lenses are in the middle left. You can see some small glass beam splitters in the center of the photo. The laser diode’s heat sink block was glued into the assembly with some strong glue. An X-acto knife and a lot of pressure broke the glue, causing the laser diode to fly across the room. Eventually, I found it on the carpet. Hopefully it wasn’t destroyed in the process, especially since it is very sensitive to static electricity.

The above photo shows both the laser diode, lower left, and the lenses, upper right. I kept the lenses hoping I could use them to help focus the laser pointer once I had the diode working.

Now I just need a circuit to power it.

Because I plan to add a lot of photos and I want to keep each web page small so they load faster, I have broken this project up into two parts. Please continue to “Part 2” to see how this project turns out!

Low Power PC - Vaio P

Thu, 26 Feb 2009 16:36:59 -0600

The Sony Vaio P has taken a lot of grief because it is a slower “netbook” than other models. Yes, it is a netbook, and yes it is slow. That’s not all bad.

First, the device runs without a fan, and if you get the solid state drive, without any noise or moving parts! And did I mention it runs Windows Vista? Yes, it’s slow, but it is usable.

I recently acquired a Vaio P and thought I’d run some power consumption tests with it. Below are my findings:

In sleep mode, charging: Not measurable (less than 1 watt)
Running, no applications, Wifi on, screen on: 10 watts
Running, no applications, Wifi on, screen off: 3 watts!

What does this mean?

1. You can have a completely silent computer with a modern operating system.
2. You can run applications 24 hours a day, 365 days a year without your computer sucking up 5 pounds of dust.
3. You can run applications like weather station software without destroying the environment in the process (using only 3 watts!).
4. The people who complain about the speed of this computer obviously do not understand the purpose or potential uses.

August 25, 2009 Update:
I have now set up this computer to post the Glenview Weather Station data to the Weather Underground. The computer is running on the desk next to me, and is completely silent. With everything powered down except WiFi, the machine does not get very hot, and uses only a couple of Watts of power.