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2014-01-12 Target Credit Card Info Hacked

2014-01-08 DC-DC Converter For High Power LED

on January 8th, 2014 by admin - No Comments

On eBay I bought a few of the LM2596 buck converters with constant current to use with the 10 watt LEDs I bought, and received them in the mail today. Now I don’t need a 1 or 2 ohm resistor at several watts to limit the current and waste power. Problem is it’s difficult to find info on the pots and indicator LEDs on the board.

The PC board has three adjustable trimmer pots and three indicator LEDs. The auction gives information about adjusting for the voltage then shorting it with an ammeter and adjusting for the current. Problem is there is nothing – no labels, no part numbers – to indicate which trimpot or LED does what. For instance, it says “The charge current of transfer lamp is default 0.1 times of the charging current (constant current value)” I’m still trying to figure out what that means.

I looked up the name on the back of the PC board and came up with nothing useful. In any case, I’ll have to do some experimenting with it and find out what’s what.

Update Jan 8 – I found that the trimmer on the right (see pic) is the voltage adjust. The trimmer on the left seems to adjust current, but when I short circuited the output (according to the instructions) the current was sometimes limited, and sometimes it went up to the half amp maximum limit of the small power supply I was using for the test. This odd behavior could have been caused by the power supply. I’ll have to test it with a wall wart that can put out more than an amp.

2014-01-05 CFLs On The Wane?

LED Lighting Renewable Energy

on January 5th, 2014 by admin - No Comments

I think that, with the price of LED light bulbs coming down to commodity levels and their long life, the CFL bulbs will become more difficult to obtain. The LED lights are more efficient than CFLs or incandescent bulbs, and there has been a steady increase in Efficiency over time, which will probably continue. Someday the volume of production will go up and prices will contnue to go down, and incandescent and CFLs will no longer be made. It’s just a matter of time before the LED production increase will bring the price down to the point where there will be no difference.

Another contributing factor is that in my area the electric company gives a rebate to the seller to make the price lower for the consumer. They did this back when the CFLs were still high priced and it brought the price down and consumers started to buy them. Now most homes have CFLs and few have incandescents. I think the same thing will happen to the CFLs and LEDs will eventually replace them. People I talk to say CFLs don’t last any longer than incandescent bulbs (they buy cheap CFLs?), and when they find that the LED bulbs last longer and save money, they will probably stop buying CFLs

One other issue that people bring up is that CFLs have a very small amount of mercury in them. This may be used as another reason for discontinuing their sales. However most people don’t realize that the amount of mercury in the coal that is burnt to generate the electricity is much greater then the amount in the CFLs.

I would like to go back to the L Prize winner, the Philips ten watt LED lights that put out 920 lumens. I boughboughtt more than a dozen of these excellent prize-winning lights. They are uniquely designed in that they don’t have the phosphor in the LED. Instead the phosphor is in the plastic cover. If the cover is removed you see the bare blue LEDs. These lights received the prize because they received high ratings in the categories considered important.

Philips has come out with a new line of similar looking LED lights. They’re less expensive and have very good ratings. It’s unfortunate that the consumer doesn’t realize that the price of the light bulb is minor compared to the price of electricity that it uses. They could have purchased the more expensive LED lights a few years ago and the savings in electricity would have more than paid for their more expensive price. The LED light package says it will save over $130 a over its lifetime if used 3 hours per day. That’s 6 or 7 dollars a year, so in 2 or 3 years it has paid for itself.

I can’t predict the future but it’s possible the led lights will be replaced by newer technology in the near Future. One possibility is luminous panels. The thought occurred to me that when a phosphorescent toy is exposed to light it will glow in the dark for some time afterwards. When fiber optics first were developed they had a short distance of light a transmission. As time went on, purer, clearer glass was developed and the transmission distance increased until now it’s possible to transmit light over 90 kilometers or 50 miles of fiber optic cable. If the same development was applied to phosphors, it might be possible to store daylight at high levels and then the glow could light a dwelling for many hours.

Another possibility is that battery technology could be improved so that batteries last longer and don’t need replacing as often. Every home might have a solar panel array that charges the batteries during daylight and powers the lights during darkness. Much of the equipment would be modularized so that it could be easily, quickly and cheaply exchanged or replaced.

No one really knows what will happen in the future, but here’s another idea. Some scientists could take the glow inside of a firefly and transplant the genes into plants that glow in the dark so all you would need is to have some plants growing in your home. They could gather sunlight in the daytime and then glow brightly during darkness. A little water and fertilizer once in awhile, and you won’t need any LED lights anymore. And you could grow your own light bulbs!

2014-01-04 Telephone Ringer Schematic

Telephone

on January 4th, 2014 by admin - No Comments

This was drawn from the actual PC board of the telephone set. It was a cheap throwaway type telephone from long ago. Some of the part labels couldn’t be seen without removing the part. We will probably have a difficult time convincing the young kids that telephone sets had a cable that had to be plugged into a socket in the wall.

The incoming 90 volt ringer signal is rectified by D201 and if it’s greater than 5.2 volts it goes past D203 and charges the 22 uF 50V capacitor intul the BZX85C zener gets to 15V. Q202 has delayed turn-off for a fraction of a second and then the current goes through R206 to the circuits below. The 10 uF 35V capacitor charges up to the 15 volts. Q205 starts oscillating through the piezo transducer, and Q203 and Q204 switch on and off alternately, causing the transducer to sound like it is chirping or warbling.

2014-01-03 eBay- LED Lights And Remote Control

Lighting

on January 4th, 2014 by admin - No Comments

I was perusing the stuff on eBay and found a couple things that interested me. The first was the Remote Control Light Socket. It screws into the existing socket and then the light (says LED) screws into it. I’m hoping that since it says LED they did not do something funny and reduce its current handling rating to where it would not work with other types of lights. But then one never knows.

The second is a set of three white 2.5 watt LED lights for $8.00 U.S. That’s less than three dollars per light. My guess is that these may be using LEDs that are substandard, such as low light output. Whatever the case, buyer beware. Most decent LED lights are about ten Dollars U.S. or more. These do set a low price mark, though. If the quantity of LED lights being sold increases to the point where they become a commodity item, the prices may go lower, perhaps $3.00 someday.

But what I see is that in the future the amount of LED lights will drop, since there are only so many light sockets our there and once they get filled with LED lights, the only LED lighte being sold will be for lew installations and replacement purposes. But if the 22.8 year claims are true, those LED lights will be lasting for a very long time, and the replacement market will be much smaller than the incandescent replacement market. Some of my friends tell me that the CFLs don’t last any longer than the incandescents, so that may also happen with the cheap LED lights bulbs.

I would also like to add that I have had very good results with the Philips LED lights, mostly the “L Prize” lights. They have worked flawlessly, all fifteen or so that I’ve been using. I still have a few CFLs but they are in places such as porch lights that seldom get used, so they may last for years.

The last photo is of a 3V to 7000 V converter. The person holding the wires is taking an awfully big risk, IMHO. The arc is only a short distance from his/her thumb, and the high voltage could go through the thin insulation on the wires. ZAP! Time for a very humble learning experience.

2014-01-02 Incandescent Bulbs Banned In the USA

LED Lighting

on January 2nd, 2014 by admin - 2 Comments

Well, this is not new, the 100 watt and 75 watt incandescent bulbs have already been banned for awhile, but starting today, 40 watt and 60 watt incandescent bulbs will be banned. These will no longer be manufactured or imported into the U.S.A. There are some exceptions, such as appliance, fish aquarium and specialty lights, but the vast majority of lights sold are in this banned group. I heard on the news that the stores will be allowed to sell their inventory, so there is no rush to buy some.

Of course, there will be some foolish people who go to the store and stock up on several years’ supply of these power wasting bulbs, not knowing that they are just throwing away their money. Each incandescent bulb uses several more times the electricity of the CFL and LED bulbs, and the consumer pays heavily for it. The environment also pays, with increased greenhouse gases and more fossil fuel use.

I have converted almost all of my light bulbs to LED lights, and I’ve saved so much on electricity that I have been told that I’m lying when I tell people what my electric bill is. I haven’t yet had a LED bulb burn out (see Note). The ones I bought are the Philips “L Prize” LED lights. They were rated one of the best by Consumer Reports, good color rendition, low power – 10 watts – and high in other important criteria. But they were expensive, $20 (USD) each. Now a 60 watt replacement LED bulb can be purchased for much less, about half that price.

But the thought occurred to me… What happens when all of the incandescent bulbs burn out and get replaced with LED light bulbs? They’re supposed to last for 22.8 years. Then suddenly the number of LED lights being sold drops to a much lower level. What then?

I guess we’ll have to wait a few years to find out, huh?

Note: The one Cree LED bulb I bought started flickering when I first started using it. But for the last few months, it has been just fine. Then recently it started flickering intermittently again, It may flicker for a few seconds, then be okay for the rest of the day. Or it may flicker intermittently a few times in a day. It’s not that much where it’s a problem, but it’s noticeable on occasion.

The Cree LED light bulb died. First failure that I’ve had of any LED light bulb (made for home lighting use).

2013-12-31 USB Charger Cables

computers

on December 31st, 2013 by admin - No Comments

When USB was invented, I think the inventors had never thought that it would be used for so many purposes. The name Universal in USB has certainly come true. My guesstimate that much if not most of the USB cables in use today are being used just for charging devices. So I have to add my two cents’ worth about this use.

The USB specifications call for a five meter or sixteen foot limit on the length of the cable because longer cables have too much signal loss and interference and that could cause problems for the transfer of data. But using the cables just for charging doesn’t have any problem with data transfer because there is no data being transferred. So the 5 meter length of the cable does not really apply.

However the USB specification for the maximum current from the USB port is 0.5 amps or 500 milliamps. Using a longer cable can cause more losses in the charging current due to the resistance of the wires in the cable. So I think it’s a good idea to go over some simple math to find out how this could affect the 5 volts that is used for charging.

I have taken apart several USB cables and I’ve found that the charging wires are usually thicker than the signal wires. I have not examined the wires closely enough to find out exactly what size they are, so I will assume that they are 24 AWG or 0.5 mm diameter. The wire tables give the resistance of this wire as 25.7 ohms per k feet, or 25.7 milliohms per foot.

Let’s assume that the user decides to use a single 16 foot micro USB cable for charging his device at 0.5 amps. The power wires are 24 AWG and 16 feet long, but there are two wires so they have a total length of 32 feet. The resistance is 0.0257 ohms per foot times 32 feet, or .8224 ohms. At 1/2 amp flowing, this is 0.4112 volts drop. And this does not include any voltage drop in the connectors or other points. So the actual voltage at the device being charged is less than 4.6 volts.

That’s an excessive amount of loss in the cable. The amount of power loss is going to be 0.5 times 0.4112 or 0.2056 watts. The cable is carrying 5 volts at 0.5 amps, which is 2.5 watts total. The 0.2056 watts loss divided by the total power is 0.08224 or 8.224 percent of the total.

Suppose the user decides to add another 16 foot extension to the 16 existing foot cable, so the total is 32 feet or 10 meters. Now the voltage drop in the cable is over 0.8 volts and the voltage at the device being charged is down to 4.18 volts or less. The power loss is going to be double, or 16.24 percent of the total.

But there is more to this than what I’ve said. Most of the USB charging cables are plugged into the AC adapter that converts down to 5VDC at more than a half amp. Some adapters put out 1 amp, some for tablets put out 2 amps or even more. So the charging cable loss could greatly increase to double or quadruple what I calculated earlier.

Solutions

Well, I guess the most obvious solution is to keep the USB cable short and add an extension cord from the wall to the charger. Of course this doesn’t work if the charger is built into the wall socket (yes they’re available) or the USB jack is on the front of a desktop PC or similar. If the situation demands that the USB cable be longer, then keep it as close to the length it needs to be and don’t allow extra cable.

Another solution is to use a heavy cable to extend the USB cable. This could be 18 AWG speaker wire or similar. The resistance of 18 AWG wire is about 1/4 that of 24 AWG, so a cable could be four times longer, with the same resistance. A 1 meter USB cable could be 4 meters long without any noticeable increase, and even longer with a tolerable amount of increased resistance. The problem is that the user would have to make his own cable, since it doesn’t appear that any cables with heavy power wires are available for purchase. I would have to take a USB cable, cut off the ends and splice them onto a length of heavier wire.

There is another solution that may seem obvious to the reader. Why not just increase the output voltage to 5.4 volts, so that the other end would then be 5 volts under load? That is possible, but there is a risk of damaging the charging circuit in the device being charged by the excessive voltage. As soon as the battery in the device reaches full charge, the charging current drops and the voltage at the device starts to rise. If the voltage gets too high, the device may be damaged.

There is a solution to this rise in voltage. This is often used in high quality and high current power supplies. It is called remote sense. The cable has two wires for the current, and two more wires to connect the far end to the voltage regulator. When the far end voltage drops, the sense wires send back the drop and the regulator circuit adjusts the voltage to compensate for the cable loss. This requires a four wire cable, but the power wires do not have to be heavy gauge wire because any losses in them are corrected. But the cable has to be made especially for this application, and the power adapter has to be made to have this feature. It would be safest to connect the cable permanently to the adapter so that the cable cannot be disconnected and used for something else.

I have a power supply that has remote sensing, so I could make up a cable and connect it to this power supply. But I think I’ll just use a heavier cable instead. Carrying a tiny charging adapter around is a lot easier than carrying around a big bench power supply.

I once had an external 2.5 inch hard drive enclosure that plugged into the USB ports for power. Yes, it used two USB ports and had a ‘Y’ cable with two plugs on it. But this still doesn’t eliminate the voltage drop in a long cable, it just reduces the loss somewhat. But most adapters do not have two ports, and I don’t think it’s a good idea to take up two USB ports on the computer to charge something.

Update 2014 Nov 7 – I have been investigating this problem and I’ve blogged it lately. See more in my blog.

2013-12-29 Some Million Dollar Ideas

2013-12-26 High Power LED Flasher – Strobe

Flashers and attention getters Joule Thief SMPS DC-DC LED Lighting

on December 26th, 2013 by admin - 7 Comments

This is a continuation of the 2013 Dec 18 blog. It was getting too long, and so is this blog.

Update Dec 24 – I searched for high current pulse gen schematic using Google and I didn’t come up with anything near enough to what I’m looking for. I saw a lot of high tech and high priced equipment for very specialized applications. I saw some stuff for high voltage generation. I saw only a few schematics and of those only one seemed to be anything close to what I would call simple enough for the average experimenter. That was an avalanche pulse generator. And it can’t supply enough power to give the 10 watt LED any kind of brightness. I think my next step will be to go through the books I have and look for something out of the decades when transistors were most popular, like in the 1970s and 80s. Be back soon.

Update Dec 26 – Yesterday, during my encounter with some sparkling bubbly stuff [hic], I perused some old books and came up with an old schematic from the ’70s for an emergency auto flasher that uses a 6 volt lamp. I replaced the lamp with the 10 Watt LED and built the circuit on a thin piece of plywood. It uses a PN2222A for Q1 and a TIP32C PNP for the LED driver transistor. Other than that, it’s a typical flasher circuit with two transistors and a 10 uF capacitor that determines the flash rate along with the two base bias resistors. The schematic shows the transistors as being RS-20xx, which are old Radio Shack numbers. Just about any NPN will work for Q1 and any PNP power transistor for Q2, as long as it can handle well over 1 Amp. Alternative types are the BD138 or BD43

It runs down to 9V, but the speed is slow at low voltages and speeds up as the voltage increases. I think that if I put a few k resistor across the LED it might help make it run at lower voltages. I turned the PS’s current control up to maximum, which is 1 amp, but the voltmeter still dips slightly when the flash occurs, which means the power supply is going into current limit mode, so the flasher is drawing over 1 amp peak. The high current pulse is too fast for the current meter to respond, the needle just flicks up a bit. I put a half dozen 10000 uF capacitors across the power input, and a 180 ohm resistor between the caps and the power supply. I adjusted the PS until the voltage across the caps was 10V, and measured the current. Even though there were 60000 microfarads on there, the current still jumped around a bit, but I got a bit under 2.5 milliamps average current. I can safely say that the current is 2.5 mA or less at 10V, which is the maximum rating of the capacitors.

The intensity of the flash is extremely BRIGHT! Like, exceedingly, overwhelmingly bright. I covered the LED with a piece of black electrical tape, and lifted the corner so the flashes came out away from my eyes. They hit the piece of paper on the table and between the flashes the reflection off the paper left a square of dark in my eyes. It’s bright!

Update Dec 27 – I took the power flasher along with me to the restaurant to eat with a friend, and I grabbed a 9V battery and some clip leads. I wanted to show my friend how bright it was. I clipped the battery on but it refused to flash. I added the 10000 uF capacitor, and it still refused to flash. Either the battery was low, or the flasher wouldn’t flash on 9V, which was what I found when I tried reducing the power supply voltage down below 10V.

The idea that I came up with was to replace the 9V with one of my 1.5V to 9V DC to DC converters. The converter is perfect for this application. The flasher’s average current is less than 3 mA at about 10V, so that comes to about 30 milliwatts. The typical Joule Thief puts out about 66 mW, and draws about twice that from the single AA cell. So if the converter is about 50% efficient then the current from the battery should be about half of the normal JT current. That means the Joule Thief will easily have plenty of output to run a single power flasher, or even enough to run two of them.

This morning I drew up a schematic of a preliminary circuit. It consists of two sections; the power flasher itself, and the Joule Thief power supply. This afternoon I built up the Joule Thief power supply section. It boosts the voltage to 9.5 to 10.5 volts. It does have a quirk, though. I used a 2200 uF 16V capacitor across the output to act as a reservoir to allow the flasher to draw a very high current for a fraction of a second. When this large cap charges up the JT power supply shuts off and the voltage drops down, then it kicks in again, sort of like an oscillation. I’m going to have to investigate further.

2013-12-24 Other Ideas For Gravity Light

Free Energy LED Renewable Energy

on December 24th, 2013 by admin - No Comments

Kirk commented that I could hang the Gravity Light from the attic and let the weights drop into the basement. Problem is I don’t have a basement, and my attic isn’t much bigger than 3 feet (1 meter). I wouldn’t gain enough to make it worth cutting a hole in my ceiling. One guy once told me that his friends and he dug a hole in his back yard. I don’t think I want to go to all that work.

My latest brainstorm is to make two ramps, each with a two wheeled ‘cart’, with one much heavier than the other. The carts would be tied to the rope. The length of travel could be 1.4 times longer if the ramp was at 45 degrees. If the ramp was at 30 degrees, the length would be longer but the weights would have to be much heavier. It would probably require a pulley at the top of each ramp. But then things start to get expensive, like building the ramps, and it’s more complicated. As the system gets more complicated and has more mechanical points, there is more loss from friction and more points for wear. And the ramps take up a much larger area.

Then I had another brainstorm. I could make the rope an endless loop. I then would move the lighter weight from the Gravity Light to the floor, and move the heavier weight from the floor to the Gravity Light. One problem I have is to get the splice in the rope to be very small, so that it will pass through the Gravity light just like the rest of the rope. I’m not sure that I could do it without some form of mechanical joint, and then I don’t know if the joint will go through without a problem.

Another brainstorm I thought about is to use the heaviest weight that is filled with water. At the bottom of its travel it would trip a valve that lets out the water into a container. The weight becomes so light that it resets itself to the top of its travel. The container is manually lifted up and poured back into the weight. This could be extended to a system that runs off a small amount of running water. I once knew a guy who had a tiny spring coming out of a crack in his back yard. The amount of water may have been only a few cupfuls a minute, but over time it could be held in a reservoir and then used to power one of these lights.

I thought about several other ways to do the job, from a water wheel to a few more mechanical schemes. But they all require more materials and are more expensive, and possibly more unreliable. The trick is KISS, keep it simple, stupid. That way, the contraption stays somewhat idiot-proof, at least until a bigger idiot comes along…

The sun will soon be setting and it will be Christmas Eve. So have a Merry Christmas and Happy Holidays, too.

2014-01-12 Target Credit Card Info Hacked

2014-01-08 DC-DC Converter For High Power LED

2014-01-05 CFLs On The Wane?

2014-01-04 Telephone Ringer Schematic

2014-01-03 eBay- LED Lights And Remote Control

2014-01-02 Incandescent Bulbs Banned In the USA

2013-12-31 USB Charger Cables

2013-12-29 Some Million Dollar Ideas

2013-12-26 High Power LED Flasher – Strobe

2013-12-24 Other Ideas For Gravity Light

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