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Saturday, December 29, 2007

Water Fuel Cell - fixes and more tests

The container is now air tight. This allowed me to start doing some electrolyser efficiency tests. By attaching a small hose between the container and a small flask containing some water I could see how fast the bubbles would form, by varying pulse width and frequencies (both the carrier signal width/frequency and also the gating signal width/frequency).

From the tests carried out so far I could not see a relationship between frequency/pulse width and the ammount of gas formed. I could only see that as the current increases, the more gas is produced (i.e.: the rate at which the bubbles appear in the water flask is greater). And the current increase depends on the pulse width alone (or not entirely - considering that the WFC behaves like a capacitor, current will also depend on the frequency).

The experiment setup, including the water flask, where the gas output goes:

The bubbles containing H2 and O2 mixed-up:

Monday, December 24, 2007

Water Fuel Cell - more improvements

While the air leak problem have not yet been solved, other problems are now fixed, and some improvements have been made. The control circuit have been verified, and it was found that the 7805 regulator that was being used, didn't had the GND pin connected (oops, minor mishap). In spite of that the two 555 timers would work, as the regulator would let the input voltage pass through. The output signals were not however perfect square waves. As the GND was hooked up, the MOSFET would no longer switch from cutoff (the 4 volts output from the second 555 would not be enough to activate the transistor). So the 7805 was replaced by a 78L09 and the circuit started performing normally, delivering a clean signal to the cell and smaller heat buildup in the MOSFET.

Another change was the addition of a small piezoelectric speaker to the container of the cell. This causes the soundwaves to propagate inside the water, eventually contributing to frequency stimulated breakdown of the water molecule. At a later point comparative results from using and not using this element will be analised in order to assess if it plays a role in turning the electrolysis process more efficient.

The speaker is connected in parallel with the load (the Water Fuel Cell), and it can be heard while at audible frequencies:

Monday, December 17, 2007

Starting to bust water into its basic elements

The basic electrolyser design is finally finished. After a lot of steel cutting and drilling, I've finally finished the first prototype of the machine which will tell wether or not pulsed electrolysis of the water, through special frequency and pulse duration control, can by itself be the key to making the process several times more efficient than conventional DC electrolysis.

For now there are a few issues to resolve, namely:

  • Make the seal on the top cover air tight - even though the container was bought under the premise that it would be air tight, in practice is was verified that it was not;

  • Control circuit FET transistor is heating up too much under a 4 Amps load - must check if the gate voltage is being enough to cause it to switch from cutoff to saturation and not somewhere in between. According to the device datasheet, it dissipates up to 150 Watts of power. In this case it has to dissipate around 40-50 Watts of power (10 to 12 Volts at 4 Amps), which is probably too much for the 25 cm^2 heat sink installed.

This is the complete setup (electrolyser + control unit + DC power supply):

4 Amp run (12 V):

No load applied:

Typical signal applied to the cell (10 ms/div, 5 V/div):

Thursday, December 6, 2007

Water - alternate fuel source and a panacea for mankind?

When it comes the time to pay after filling up the tank, you dearly wish your car could run on anything cheaper than stinky old gasoline (or diesel). Wouldn't an entire global economy depend on this precious product, and you could establish a parallel with other things like drugs, where the desperate sense of necessity leads to the unavoidable obligation of paying a large sum of money just to obtain a given ammount of it.

It's a sad fact, however, that in this business the whole world is an addict, and just like with a junky, the side effects of this condition are starting to show up.

And where drugs exist, dealers, cartels, entire webs of traffic make up the building blocks of this entire business. In the oil world, the same entities exist, with different names and covered in the umbrella of legitimacy.

If it wouldn't be legal the entire world would stop: people could not run their cars to go to work, airplanes wouldn't take off, ships could not carry goods across oceans, and so on.

Now imagine a world like ours, where oil dependency would have seriously compromised the health and survival of its population, by letting polluant agents released by oil combustion damage and destroy the existing natural resources. Until one day a man finds that using a not very complicated process, water could be splitted in hydrogen and oxygen, just like with electrolysis, but requiring a very small ammount of energy in an equation where the profit margin, i.e.: the hydrogen obtained in return, would be many times greater than the energy spent in the process. With this invention this man would have killed the oil industry, simply because 70% of the earth's crust is covered by water, whereas oil certainly only makes up a tiny fraction of this value, and falling. And as if this wouldn't be enough, instead of the many toxic gases released by the conventional fuel combustion, hydrogen combustion only releases...water vapour. But the oil industry could not disappear. The relationship between oil companies and governments, and ultimately between governments and other nations would be complex, and oil would be the glue holding things together. And like with so many other things in life there would be a consistency that we wish we would not see: the nations holding the greatest share this product would happen to be those with the greatest deal of conflicts, internal, or with the rest of the world.

Oil could well be the only narrow stream of understanding, or the very reason why they could have the arrogancy of turning against the entire western world. In one way or another making oil obsolete would not leave the world serene like with any other useless invention. Liken anyone or anything threatening a multi-billion dollar industry there would have to be a price to pay, or a long fight before this miracle of mankind could see the light of day. In this hypothetic world, the mastermind behind the magic key to salvation would no longer sleep at night with the same serenity as before. And not without reason. After all the entire nation would watch his steps, and secretly conspire against his existence, in an attempt to suppress any threath against the value of oil in the global economy, where his country would have a lot to benefit from. But as a self ensured man he would be, nothing prevented him from patenting his invention, and going ahead with his plans. Indifferent to any declared threats, went ahead with his plans, convincing investors to finance his project. One day, the man shows dead. Forensic diagnosis declares the cause of death as natural and no murder hypothesis is put on the table. The man was healthy, without
record of health issues. However no other option is considered, and investigation finishes short after the occurence.

What about if I told you this world is the real world we are living in, and that this man in fact existed, and was called Stanley Meyer? You probably wouldn't believe the story, like many scientists don't and I personally am scheptical about believing it entirely. It's not because the world is sick (because it is) nor because brilliant inventors are persecuted until they give up on their findings (if there is an unofficial yet governamental inconvenience that the invention be successful, they are persecuted), or because this would be a brilliant solution to stop the pollution caused by oil (as it would), but because it seems a bit farfetched as with simple technology a single person would be capable of doing better then what years of research and development from the automotive industry haven't achieved. Without mentioning that this would be in violation of the laws of physics currently accepted.

However, giving the benefit of doubt and following the enthusiasm driven by the fact that quite a considerable amount of people claim to have already surpassed the laws of Faraday with their homebrew apparatus (by producing several times more hydrogen than would be expected from the energy that is put into the system), I decided to pick up the patent from Stanley Meyer, and attempt to build the device myself, in order to be able to see with my own eyes if there is a confirmation of this idea, or if instead this is no more than a hoax or product of a urban myth, grown in the mind of this complex person.

So here are a few images of the unfinished prototype, which include the control device, wich powers the electrolysis cell with a pulsed current (this includes variable frequency, duty cicle, and variable gate frequency and duty cycle), and a glass flask for single cell cell test run (the definitive design will be put inside a larger stainless steel container with a set of 6 cells, and capacity for a total of 9 cells):

Each cell is made of two stainless steel tubes (304 grade), arranged in a coaxial configuration where the inner tube (15 mm in diameter) and the outer tube (18 mm) and spaced by approximately 1 mm. This 1 mm thick region is where the electric field is formed, and where the water splitting process takes place.

Cell in activity:

Signal applied to the cell:

Sunday, June 10, 2007

"Long-Haul" point-to-point WiFi links

I start this blog with a great, not so new idea, that I decided to reimplement and see working with my own eyes. The principles behind it are not new at all and go back to the early days of RADAR technology (1930's), in a time where microwave radio research was taking place to improve the accuracy of this type of equipment. The need for guiding radio waves through a low loss medium and to be able to selectively pickup signals coming from a particular direction (in this case echoes from the emitted pulses) led to the design of different types of microwave antennas. These antennas had to be both compact (in order to fit into small airplane compartments) and efficient (output most of the signal from the transmitter in a particular direction and receive with exceptional gain the signal returning from that same direction).

At the time, these technologies were mostly closed under military secrecy, both because there was no justified civilian application for it and because of the war context in which these researches were taking place.

Later, microwave radio applications became widespread, both in civilian aviation, weather forecast, telecommunications and in the domestic life - microwave ovens. Necessarily most of the products of these early researches became public, including the antenna designs.

Today we are buried in microwave technology: ovens, satellite TV, GPS, GSM/UMTS/CDMA cell phones, DECT phones, garage door openers, Bluetooth, WLAN. All of these technologies have the particular feature of transmitting and/or receiving signals at small or very small radio wavelenghts - WLAN for example, transmits signals at a wavelength of about 12,4 cm. Comparatively the radio signal from an FM radio has a wavelength of 277.59 cm.

This means that a microwave antenna to be efficient doesn't have to be huge, like it would happen with FM radio antenna.

With microwaves, a moderately low power directed signal can travel a long distance and be detected at the other end with a compact antenna, as long as it is accurately pointed towards the emitting station. Thanks to this, a user with a satellite TV antenna can pickup a signal coming from a satellite 36000 km away that is transmitting only 70 watts of power (about as much as regular light bulb) with exceptional quality. Comparatively ground TV UHF transmitters require several hundreds of thousands of watts for a few hudreds of km of coverage (a moderately muscled car produces about 100 kw of power). So we could compare the costs of a UHF transmitting station with the fuel consumption of a few sports cars running together 24 h/day at top speed.

In spite of low energy consumption and very large signal coverage, transmission sattelites are of course, not cheap to deploy and maintain.

But, for us in our domestic endeavours, some things can come cheap in microwave technologies. WLAN is already common place everywhere, being a very convenient way of bringing network connectivity to computers and other devices, where mounting cables might be impractical and expensive. The performance of this type of LAN thechnology have also improved over time, so that in many cases is an interesting replacement to regular wired LAN technology.

Even though WLAN is very interesting as a local network technology, it becomes even more interesting if we take the challenge of making it a little less local. This is where the radio antenna principles from the 1930's come into place. Regular WLAN hardware, such as Access Points, Client adaptors, Routers and Repeaters all have small omnidirectional antennas with a gain rarely exceeding 2 dB. Most of these devices however, provide an RP-SMA plug, allowing the user to upgrade to a better antenna. But, by searching the market for alternate antennas, we see that these are in general expensive, sometimes too expensive for the expected benefit - for example a Linksys HGA7S with an announced gain of 7 dB, can cost up to 65 €. This is above the price of many AP's and client adapters.

The challenge I've decided to undertake was to build a much better solution for a much lower cost. This tourned out easier than otherwise expected.
Antenna design:

Based on this procedure, two equal waveguide antennas were built, using common materials. The total cost with materials did not exceed 30 €, and the resulting antenna set had an expected gain between 10 and 12 dB. A few objects such as the tripod and the tin cans were reused, representing a null cost. The most expensive parts were the alluminium foil and the coaxial connectors used. The RG-58 cable was not expensive but the choice was not optimal. LMR-200 cable would have been a better choice, as it features smaller insertion loss in the 2.4 GHz band. As the length of the cable is small (1 m) in this case the impact is not very substancial.

The "cantennas" were attached to a tripod from a telescope, even though a regular camera tripod could be used with this design (A 12 € tripod from a chinese store should do the trick):

Using small wood ribbons, four platforms were made in order to support the antennas and allow individual azimuth adjustment:
These were fixated simply with nuts, bolts and washers. Hot glue was used for the nuts that hold to the telescope tripod. If the antennas were to be attached to a regular camera tripod, the platform at the bottom could be discarded, as the nut would directly fit into the tripod screw.

Copper wire was used for fastening each can to each individual wooden support. Other materials can also be used as long as these provide adequate grip for the can.

The 31 mm antenna header as mounted in each antenna, soldered directly to the N-type connector. This value should be measured from the connector insulator to the top of the wire. It is best to cut the wire above the required length and after it is soldered to the connector the size be adjusted to the required 31 mm:

For improving the can performance, some aluminium foil was used to extend its length to 185 mm. Additionally alluminium funnels were added to each antenna. These provide about 3 dB extra gain to each one. Both the aluminium cillinders and funnels were hot glued to the cans:

In my prototype, I found convenient a Wireless Repeater. This model (an SMC WEBT-G) only had one RP-SMA connector, so I added a new one and removed the internal butterfly antenna:

The old 1.5 dB external antenna and the 2 dB butterfly antenna (the coaxial cable from the butterfly antenna was reused for the additional connector):
Experimental Results:
From the limited tests performed so far, the results seem exceptional from the point of view of a person who never played with antennas better than 2 dB of gain. Aiming the antena to a block of buildings roughly 200 m away with several obstacles in the path provided 45 % of signal strength for some of the AP's located at those buildings. Given the fact that there is no line of sight path between stations, it is quite a satisfactory achievement.

In a later iteration more tests are expected to be executed, including range tests in a line of sight path between two antennas of the same type. Other people having built this type of antenna have reported to achieve a link between stations 3 km apart, without any kind of amplification (just the 100 mW or less of output power from the AP/client adapter).

Future projects:
  • create a WiFi dish antenna with an expected gain of 30 dB, using an old satellite TV dish and a biquad antenna as the header;
  • modify the funnel antenna by adding parasite elements to further improve performance;
  • create a standalone biquad antenna and test its performance.