Archive for the ‘Electronics stuff’ Category

Legacy Pan-Tilt for Video Camera

22 April 2017

pan-tilt for video camera

pan-tilt side cover removed

This piece of “legacy” tech isn’t much to look at. It was the first item I photographed but the last I am making a post about.

I got it from my brother when his company upgraded all their video equipment to more modern stuff.

This was possibly made to sit on a pole and hold one of those large surveillance cameras that you still see some places. But this unit was being used inside to hold a camera much smaller than it is (though heavier than modern cameras that are fully electronic).

pan-tilt with main cover removed

It originally had a long control cable so it could be moved around from a remote location. The controller (shown underneath) simply switched the motor drive voltage (about 24 volts AC) between four different drive windings on two different motors – forward and reverse for each motor. There are little switches installed in the housing to turn the motor off if it tries to move beyond the mechanical limits of the housing. And that’s all there is to it.

With the advent of much smaller cameras, pan-tilt units no longer need to be this large and heavy.

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Voltage Divider Assembly

10 April 2017

voltage divider assembly inside
A few years ago I purchased a pair of differential voltmeters because I was looking for aluminum equipment cabinets and thought these might work. The front panels were actually a full 1/4-inch think, which was a little more than I bargained for. These were military-grade equipment, and I think both of these items had been in use by the Army.

I got them from Fair Radio Sales “as-is.” The shipping cost almost as much as the equipment did. These meters were made by John Fluke Mfg Co, Inc, of Seattle in the early 1960s. They used mostly vacuum tubes and various other technologies now considered Legacy. The idea behind a differential voltmeter is that you compare a known voltage with an unknown one, and use a meter to tell when they are equal. The settings you used to get the known voltage are then equal to the voltage you wanted to measure. Ponderous. Today’s digital voltmeters do the same thing, except they “turn the dials” for you and present the result on a readout screen.

voltage selection dials

Marked dials function as an old-school digital readout.

This assembly is just the voltage divider for the known voltage. It consists of a set of switches and precision resistors arranged so that when you put in a reference voltage, the output equals the voltage you dial in. For accuracy, the resistors used have to be high-precision. These ones have a tolerance of +/- .02% which these days is unheard of. I saw a refurbished working version of this equipment for sale for over $1,000. It’s considered an ultra-precise laboratory-grade device.

inside the voltage divider

From what I can tell this equipment was entirely hand-assembled. That was how it was done in the “old days” of electronics. The colors involved are kind of pretty but they also served to help the assembler be sure he or she had the right part or was sticking the right wire in the right place. All the resistors were made of lengths of fine wire wound onto forms then glued in place with clear paint. Fluke may have constructed the rectangular ones themselves. The yellow cylindrical ones were made by an outside firm.

voltage divider back side

I couldn’t get over the workmanship put into these components, so I kept one of them. But this one is now extra and is destined for the recycling center.

High Voltage Divider

8 April 2017

100KV high voltage divider

Here’s another piece of “legacy” technology. However, in this case the manufacturer, Spellman High Voltage Electronics Corp in New York, still offers this device as the HVD100. This is the smallest model, for up to 100K volts. That’s 100,000 volts. The input voltage can be monitored at a ratio of 1,000 to one, or 100V full scale, or at 10,000 to one, for 10V full scale. The total resistance of the column is 1,000 Meg ohms or 1 Gig ohm.

I bought this unit on eBay as basically a piece of junk. I was curious what it was, as the description wasn’t clear. It arrived slightly damaged. I disassembled it and altered it a bit to strengthen it and make it easier to take the top and bottom electrodes off. All the rounded parts are for the purpose of reducing arcing. Arcing will interfere with measurements, creating momentary lower-resistance paths across the device. However, the top and bottom electrodes make it really clumsy and difficult to transport. It is designed for laboratory use, and includes a sparse but descriptive label and BNC connectors to attach measuring equipment.

high voltage divider detail

As with many of the items I have kept around, this one has a certain aesthetic value, but I never use it. Though I find high voltages exciting, they are difficult to produce and dangerous to handle, and really beyond by current experimental capabilities.

Depth Sounder

3 April 2017

Here’s another piece of equipment destined for the dustbin (or in this case, electronics disposal center). I found this a few years ago at the Goodwill Outlet in Seattle. As far as I know, it is totally functional.
It does, however, lack the transducer needed to make it work on a boat.

legacy depth sounder

Location by Echo

Radar, Sonar and related distance-finding technologies all operate on the basis of echo-location. It’s a clever system, because you can measure both distance and direction from just one point. With visual methods you need two or more points to view from so you can triangulate.

In the case of this device, the transducer is fixed to the bottom of the boat, so it only points down. Thus, “depth and fish.”

Whereas cheaper versions are geared only to tell you how much water you have under your keel, this one is rigged to display multiple echos from different depths. Judging from the difficulty I had in finding the user’s manual for this instrument, I would guess it was built and sold before internet shopping became popular. Modern versions still operate on the same principle, but are computer-based.

Here’s the electronics:

depth sounder electronics

Relatively simple. It operates on the boat’s battery, 12 volts. There’s a connection for the transducer (I moved it from the back). There’s a motor to spin the lighted indicator, and some logic circuits. If you’re into electronics, you’ll also notice some RF (radio frequency) parts on the board. Per the manual, the transducer operates at 200KHz. That’s RF, and as sound, classifies as ultrasound. It’s ten times higher frequency than what we can hear with our ears. I don’t know about fish.

Toroid Transformer

26 March 2017

This is the first of a short series devoted to items of technology I have run across in my pursuit of my electronics hobby that were once “cool” but are now seldom used. Most of the things I will show here are destined to be thrown away or otherwise disposed of, as I have found no use for them, either.

The Toroid

The toroid is a big deal in some branches of New Age Physics and is a significant concept in regular physics as well.

Technically, “toroid” describes the shape of a torus or similar geometric object. It is, however, used as a noun. The shape is, colloquially, a “doughnut.”

Coils wound on toroid cores have been around for a long time, as they have certain advantages to cylindrical coils or square transformer forms. The magnetic field they generate tends to stay inside the core, so they emit less electromagnetic interference.

Toroidal parts are a little tricky to manufacture, but the need for them has become so great that they are now commonplace. However, 60Hz (or 50Hz) power transformers are a rarity in electronic equipment nowadays, having been replaced by high-frequency transformers. They are still used in electric power systems.

My Transformer

toroidal-power-transformer

This transformer came in a video distribution rack made by a company called Sigma, probably around 1995. The primary takes line voltage (120VAC) and the secondary outputs about 30VAC with a center tap. It was used to make a +/- 15V power supply. That power was fed to amplifier modules that created +/- 12V rails using on-card linear regulators. The amplifiers were high-power op amps connected in current mode. They only needed a voltage gain of 2. Each card had two. This was for old composite video. Composite video is out of style now, so all the equipment that was made for it (and there was a LOT!) is now just this side of junk.

The future of legacy technology

Does old technology have a future? SciFi writers have speculated about this. What if this planet gets downgraded and we can’t make modern technology any more? Would older “junk” technology help us recover? And what if we travel to a distant planet that turns out to be less advanced than ours? Would it help to have an older technology available that would be usable there? These are actually ancient questions, but not even LRH ever really goes there. It gets mentioned in accounts of ET history every now and then. If the true data about Antarctica ever gets released, it would be quite a revelation, and this question comes into play in those ancient events.

But I must say, this thing weighs about 5 pounds and is now replaced by technologies weighing less than 1 pound. You could never take it into space using our rockets. But should I keep it as a novel paperweight?

toroidal power transformer upright

It is somewhat interesting to look at.

I just got chipped.

24 July 2016

mastercard promo piece

A replacement debit card arrived in the mail today. I got an email from my credit union saying it would be coming. It has an electronic integrated circuit “chip” in it that is supposed to make transactions more secure.

Well, fine. Who cares? They are trying to deal with all the credit card fraud going on around the world.

But for anyone familiar with the alternative realities community, this connects directly to something Aaron Russo and many others were talking about for a long time.

The whole agenda is to create a one-world government where everybody has an RFID chip implanted in them…there will be no more cash — and this was given to me straight from [Nicholas] Rockefeller himself…
– Aaron Russo from 2006 Alex Jones interview

Russo died in 2007, five years after learning he had cancer.

The current experimental model, which has been reported on television and implanted under the skin in many people, is not exactly a “chip.”
public version of RFID chip
It’s a tiny tube with some electronics in it, and a pickup to energize it when it is scanned, like other RFID technologies.
RFID chip diagram
The implant contains only an ID number or code. This is fed into a computer which connects to one or more databases that might contain more data about the person. A pilot program in Atlanta was using it to connect to a medical database to help with emergency treatment situations.

ET

It has been stated by numerous researchers and experiencers that real (and “faked”) ET abductions often include insertion of an implant. When these are found (by x-ray usually) and surgically removed, they are usually described as “biological” or “bio-electronic.” That kind of implant is certainly more sophisticated than what we are seeing in the mainstream media. And reports say it is much more invasive, too.

How important is this?

These devices are certainly real. The low-tech versions pictured above have been released to the public, and other versions have been studied.

To the extent that they can be implanted without the knowledge of the carrier, they can be used as a covert method of tracking people. And their capabilities could include mood alteration, thought control or fake telepathy, and triggering of hypnotically-installed programming.

But to the extent that they can be detected and removed or deactivated, they are not a reliable control technology. Of course, we could be forced to use them, as people are forced now to take vaccines. But that would be a too obvious totalitarian ploy. So I don’t think they will come into wide use unless the totalitarians gain a lot more control than they have now.

The chip in my new debit card, however, is another matter.

As a long article at Wikipedia explains, the card issuing institutions (a few major banking companies) are forcing businesses to upgrade their card processing equipment (also known of Point of Sale equipment, or PoS – confusing because this acronym is already in use to mean “piece of shit”) by re-writing merchant contracts to stipulate that merchants will be responsible for all fraudulent transactions on non-upgraded equipment.

Meanwhile, many cyber-security researchers have tried to demonstrate that the new equipment can be fooled just like the old equipment could be. But the banks are having none of that; they are pushing ahead with what looks like a target date of October 2017 for full implementation.

My take is that bankers at the consumer level have become desperate. Their technologies are hackable and it is costing them money. Even after they stopped paying consumers interest on their savings, and though they charge very high rates for purchases on credit, a general surge of financial crime is continuing to squeeze them.

I think it is quite possible that criminal elements in the banking system are trying to force a collapse in consumer banking by pushing weak-security-by-design technologies, then financing the credit card hacking industry. People are just having too much fun with their credit cards. And this whole “false flag” paradigm has become such an obvious modus operandi for well-placed criminal groups in recent years, that I have come to suspect it is in use whenever I see a suspicious “problem” like this one persist. I am just guessing in this case, but the possibility for something like this is very real.

The use of the term “gold chip” is at one level a marketing stunt and at another level a slightly sinister play on words. This could be the “chip” that Russo was told about! Take away cash, or make it very scarce, or worthless, and a card with a “gold” chip in it will be the only way left to transact business in the “legitimate” economy. Back to the days of Roman gold coins!

The criminals have the consequences of their actions totally justified. They don’t respect what little dignity human life has left. They hate it and themselves. It is much more important to realize this and out-create this suppression than it is spread doom-and-gloom about our future. The doom-and-gloom are inevitable if we don’t out-create the suppression. So why dwell on it while we still have a chance to escape it?

And as for ET and their implants? I recommend the same basic approach. Treat them as criminals until they reveal themselves and prove otherwise. It’s probably the truth in most cases.

Electronics Project – Technical

21 December 2015
V-I box front panel

Front panel for my “V-I Box” – reused Extron video equipment.

This is a technical article about a project I recently finished (for the most part). It doesn’t work that well, but it is quite complex so gives me a chance to cover several topics while talking about just one project.

V-I Box

V stands for voltage, named after Volta, an Italian.
I stands for current (French intensité de courant) as used by the French scientist Ampère.

In electricity and electronics, any component will have a characteristic “V-I Curve” showing the relationship between voltage across the component and current through the component. These days, we usually use “curve tracers” to get this graph, but you can also plot it a point at a time using a variable power supply.

Last year I had constructed such a variable supply for a little presentation I gave at work about transistors. Later I made another one to use to demonstrate the operation of vacuum tubes. I wanted to preserve these projects (and the parts used in them) in a more compact space, so I decided to squeeze them into an old Extron (video processing equipment maker headquartered in Anaheim CA) enclosure. The photos show what resulted.

The design is far from ideal but retains most of the features of the older designs, while making some changes to increase the current capacity of the lower voltage source and keep part of the Extron front panel.

Following is a discussion of some of the features of this project.

V-I box guts

Inside my project…

Creating a 1-250V variable supply

I was not prepared to create a supply that could ramp from 1 volt to 250 volts in one smooth transition, so had procured several power supplies, 4 50-volt supplies, a 25-volt supply, and a 1-25 variable supply in the form of a DC-DC converter.

I then had to create logic that would switch through the supplies in 25-volt steps. As part of this scheme, the supplies are put in series (or “stacked”) with each other. This is only possible because most power supplies (not some of the old tube ones, though) use isolation transformers so that the output and input can be at different DC levels. This isolation usually works up to at least 1,000 volts.

The high-voltage sub-system receives a binary code (from 0 to 255) and must decide how to connect the supplies to get a supply voltage about equal to the value of the code supplied.

To implement this I used 4 relays using 5-volt coils, so I could use logic signals to switch the voltages. The DC-DC converter was a cheap one using a potentiometer to set its output value. To make it variable by remote control, I had to set up a control loop using an op amp to drive an optical isolator. The output transistor of the isolator would server to replace the potentiometer.

Other voltage sources

My earlier designs had two other voltage sources, one to bias the tube grid or transistor base or gate, and another for the tube heater. I used a low-power op amp to supply the bias voltage, as hardly any current drive is needed, and I thought +/-10V would be a sufficient range.

I had used a variable linear voltage regulator for the heater voltage, but in this design decided to leave that out and just make my 5V control electronics supply available for that use.

I also needed a supply to run my DC-to-DC converter. It is a buck converter, so I needed greater than 25V. And I only had +/- 12V rails and +5V available from my control electronics power supply. So I used a boost converter driven by the +12V rail to get about 30V which I fed to the buck converter.

Measuring voltages

Providing panel meters for measuring instruments is always a challenge. Today the most common design uses a microcontroller with an A-to-D (analog-to-digital converter) driving an LCD (liquid crystal display). However, I had already purchased a bunch of little modules for the earlier boxes and wanted to use the. So I fit four of them into the new panel. All they do is display the input voltage when powered by at least 5V. These modules have about 370K input resistance and can display up to 99.9 volts. You can get all kinds of different ranges. As I wanted one display to show the entire range of output voltages, I had to divide the input by ten and settle for 25.0 maximum readout. The other module is used for the 1-50V segment of the output supply, and operates at full 3-digit precision. The bias voltage is displayed on the LCD that came with the original equipment.

Measuring currents

In modern electronics, currents are always measured by converting them to voltages first. The old analog current meters responded directly to input current. To convert a current to a voltage, just pass the current through a known resistance, then measure the voltage drop across the resistor. This may then be amplified if needed. In my case, I needed to amplify the signal so that I could use my little voltmeter modules as current meters. (You can also get modules that have this capability built in.)

For the “heater” (+5V supply) current, I used a 0.2 ohm resistor. This would drop 1 volt at 5 amps, so I needed to amplify it to give my meter a range of up to about 3 amps (reading of 30.0). I used an op amp in “quasi differential” configuration to get this reading, so I could put the resistor in the high side of the 5V rail.

For the main supply I used a 4 ohm resistor, as I expected to draw only about 30ma maximum (30.0 reading) from this supply. 30mA through 4 ohms gives a voltage drop of 120mV, so I had to amplify this by a gain of 250. I used an op amp in non-inverting configuration for this purpose.

I used the 30V supply driving my DC-DC buck converter to power these op amps. This was close to their maximum supply rating of 32V!

Front panel controls

The front panel that came with the Extron equipment had an LCD, some pushbutton switches, and 4 little knobs. The knobs felt like potentiometers, but they turned out to be rotary encoders. Instead of replacing them (would have been a lot simpler) I decided to use an Arduino to make the rotary encoders function like digital potentiometers. This was handy for controlling the high voltage supply, but was overkill for the other variable supplies.

It took some fiddling and internet searching to get some workable code for the encoders, but once I got it, they worked satisfactorily. In order to convert the digital values back to control voltages, I had to send them out to a 32-bit shift register and then run R-2R ladders from those 4 8-bit outputs to get analog values. As the bias voltage needed to be bipolar, I wrote the code to display “0” on the screen when it was outputting 127. That made the control voltage for -10v about 0.5 volts, and the control voltage for +10V about 4.5 volts. So I had to provide my op amp with a gain of 5 and an offset of -2.5 volts.

One of the knobs controls the LCD backlight, which has to be pulse width modulated. I found a cute little voltage-to-duty-cycle circuit on the internet which I used for this purpose. I could have used the Arduino, but had run out of PWM outputs.

The LCD

The LCD is run in 4-bit mode using the standard LCD library for Arduino. This requires 6 control pins, not counting the backlight and contrast circuits. Fortunately, the front panel LCD was a totally standard model and interfacing it to the Arduino was no problem once I found its pinout on the internet. (It doesn’t use the more common single row of 16 pins, but rather the less common double row of 14 pins to one side.)

System noise and a mitigation strategy

Worst case, this system could attempt to switch 4 relays on at the same time. Relay coils are highly inductive loads and these coils draw about 70mA each. This can produce a lot of noise on the 5V line, and was causing my system to oscillate or reset under certain conditions. Though I haven’t taken all possible steps to reduce this problem (such as running the Arduino on an isolated rail), I did create a circuit that detects whenever there is a change in the signals that run the relays, and then applies them in sequence to the relays over several seconds, rather than all at the same time. This does give the system a more sedate personality, though I have not eliminated unwanted resets.

The relays with sequencing circuits are in the upper-left side of the enclosure, as it is pictured. The 4 50-volt power supplies are underneath them.

Making connections

In a complex project, connecting all the sub-assemblies together is a huge issue. I am trying to get better at this by standardizing on .1-inch spaced headers and connectors for most applications. I have a source of cables using these connectors which can carry quite a lot of current. Most such cables are extremely flimsy and only good for signals, not power.

For the main power connections between the supplies and the front panel, I used do-it-yourself high current connectors with locking plastic housings. I used to get these at Radio Shack, but making them myself from parts isn’t too bad.

I also use old-fashioned terminal blocks for higher voltage or higher power connections. These require the use of crimp-on lugs which are not cheap. However, if you know how to use the crimping tool, and fit the wire to the correct lug barrel size, they work very well. I used to use soldered lugs for this purpose, but the terminal block strategy keeps things more modular.

Ending cycle

I spent many hours over a number of weeks on this project, and all to preserve some hardware that I hardly ever use. So it’s time to move on to projects more along my main purpose of electronic art. I’m hoping this write-up will assist me to take my attention off this cycle of action and start some new ones.

A Tale of Two Towers

19 April 2015

No, it’s not another 9/11 exposé. For my favorite on that subject see Courtney Brown’s website.

This is a little long-delayed article on making electronic equipment for a hobbyist workbench.

Here’s a view of my two towers:

the two towers on my workbench

Inception

I have designed and built a lot of test equipment for my hobby. I still do.

But a lot of it I end up hardly ever using, or using just once. I had a need. I built something to fill the need. It filled the need. And the need never returned. Or so it seemed.

But some needs kept coming up. A quick source of power. Need to measure a voltage. Need to measure a current, or a resistor, capacitor, sometimes even inductor. I had created a lot of different solutions for these basic needs and usually put them in some sort of horizontal enclosure. This was the standard approach. However, if I put the thing close to me so I could use it, it blocked access to the rest of the bench. And if I put it further away, I never used it, opting instead for something portable that I could put on the bench temporarily then put back somewhere else.

So one day (a year ago?…hard to say when for sure) I got the idea of trying a vertical arrangement. Maybe this was the compromise design that would keep the tools I needed the most close at hand without blocking my access to the rest of the bench.

I started on Tower One. I had a piece of plastic I was going to use for some sort of rack-mount project (19 inches wide) so I just turned it on its end and made a cabinet out of it.

tower one

Tower One

I wanted all the stuff I had put in past designs in this one. A bunch of power supplies, including a variable one. At least one meter. A selectable voltage divider and a bunch of current shunt resistors. And a signal generator. And since I was getting into Arduino, the signal generator would run on software.

I also wanted to include a “patch bay” that I could use to change cable connector types, as this was a constant problem.

And I came up with something.

It worked pretty well.

But after sitting on my bench for six months or so, it was obvious there were parts of it I hardly ever used. The minus supplies were one thing, but didn’t matter that much, as they didn’t take up that much space. The whole top section was not being used, either. The other parts were being used a good deal, but I wished I could monitor voltages and currents easier.

So I decided to build Tower Two.

tower two

Tower Two

I wanted to make this tower half the height of the other. I had a hard time finding a good enclosure, but finally decided to take the front panel of a rack-mount enclosure that I didn’t want and cut it in half. I used both halves, with a hinge between them. One half had the power supplies in it and the other half the rest of the electronics. I expanded my Arduino application to monitor 4 power supply outputs at the same time.

(I didn’t photograph the towers with the displays on because I thought they would just glare and look bad.)

I had to find a little stand to sit this on to get it up to near eye level, and settled on an old plastic speaker cabinet that was the perfect fit.

I simplified the “patch bay” to a few most essential connectors.

Result: I use the new patch bay all the time, but for some reason prefer the power supplies in the other tower. That’s probably because my current metering didn’t work out very well in the new tower.

I still use other tools quite often, including a little Radio Shack multimeter that I modified to work off an AC adapter, and a cute capacitor meter that I found online and installed in a rack-mount enclosure that sits to one side. This capacitor meter is very cool, as I often want to know cap values with more precision than they are marked – or can’t read the markings.

The Bench

This is probably the most productive bench I have ever used.

The Radio Shack temperature-controlled soldering iron is really nice, I have all my hand tools pretty well organized, and I don’t try to make it double as a table to eat at, as I used to with past workbenches in other apartments.

Yet the look of it is not yet that great, wouldn’t you agree? It still looks pretty messy.

Order is defined as a condition in which everything is in its proper place and performs its proper function.
– LRH
HCOPL 14 Feb 1980 Order Versus Disorder

So maybe I don’t totally have order in on my workbench yet. But at least I have some good guidance on what to do about it.

my workbench

Part of my workbench in a unusually cleaned-up state.

HDMI Exposed!

9 August 2014

It all started innocently enough…
I was wandering the aisles of my local Shopko when, there it was, seemingly alone on its shelf…a Blu-ray edition of Kubrick’s 2001 A Space Odyssey (1968). I had never seen it. Well, I thought, I should pick it up and find a way to play it…

Digital Video

Blu-ray is a data storage technology. A blu-ray optical disc has roughly 25GB of storage capacity compared to 5GB for a DVD. It uses a blu-violet laser to read the disc and a smaller spot size.

The importance of this technology to “the industry” is digital video. Digital movies have become a huge business. They are also a most potent way for corporate America (or the global military-industrial complex – however you want to look at it) to get its messages across to a live audience. Story telling has always been used for this.

In the Old Days of video, the picture wasn’t digital. It was an analog signal combined with digital synchronizing signals. It was used for TV for years. Movies used film; they still do. But now the frames of film can be digitized into digital video. They put films onto video tapes for TV shows using a similar process. Video tapes were the first way for consumers to buy movies and watch them at home. But that video was very coarse compared to the film it was made from. And so the pressure was on to bring video up closer to the quality of film. Digital video was seen as the answer.

Home movie watchers want an experience more like they get at a movie theater. And that means “high-definition” (HD) video and “surround sound” audio. People have “theaters” in their homes all set up to view movies the way they are shown in a movie theater. And blu-ray gives people a way to buy (or rent) high-definition movies on disc.

Encoding

Digital data of any type must be stored using some sort of coding system. It’s just a binary number until it’s decoded and its significance to humans (if any) is retrieved. Computer science has worked out hundreds (if not thousands) of coding schemes to turn data that means something to people into streams of binary numbers. In its digital state, data is relatively meaningless. But while in that state it can be reliably manipulated to include, for instance, encrypting, which then requires someone who wants to decode it to also have a decryption “key.” Both of these features of digital data – encoding and encrypting – are seen as valuable to people who think they have the “rights” to the data and should be able to charge others for the privilege of using it.

HDMI (High Definition Multimedia Interface)

When I got home with my blu-ray disc, I discovered that none of the optical disc players in my house were blu-ray compatible. That means I had to purchase a player. I looked online and found a refurbished one at NewEgg for what I thought was a reasonable price and purchased it. When it arrived a few days later, I found out that the player had only one output on the back: HDMI.

I had heard of HDMI, but I had no equipment that used it. My DVD player outputs analog video and audio; easy to make copies from this output. But HDMI is totally digital; difficult to make copies from this output. That’s why “the industry” likes it!

Actually, the HDMI system is pretty cool. It has four channels of very high speed digital, transmitted on “differential” twisted-pair lines the way ethernet signals are. These channels can go really fast. That means they can squeeze high-definition video PLUS up to 8 channels of digital audio (32 channels with version 2.0) through an HDMI cable, plus let the source of the signal “talk” to the receiving equipment to ensure all licensing fees have been paid by the manufacturer of the receiver!

None of this solved my problem of not yet being able to view the movie I bought.

And I didn’t see buying an HDMI TV ($500 and up) as an option.

Handling the video signal

Video is relatively easy with HDMI. I have computer monitors with DVI inputs (another digital video connection system) and the signals are compatible. Just get an adapter that has DVI on one end and an HDMI connector at the other. Then connect disc player to monitor with an HDMI cable.

Problem: No sound!

Handling the audio

Older blu-ray players had analog audio outputs (I am told). I couldn’t find one. I tried a gizmo that converts HDMI to VGA video (that’s analog but for computers) and analog audio. My player talked to it and decided it wasn’t licensed. Nothing came out!

At this point I went a little crazy. I tried my best to research it all out on the internet and make the right decision. From what I read it sounded like I needed an “A/V Receiver” and maybe even an “A/V Preamp.” A/V preamps specialize in pulling the audio out of HDMI signals. They are considered “top end” and are très cher (very expensive). Not an option.

I settled for an older A/V receiver. It had lots of audio amplifiers. If worse came to worse, I could use them for something else. It had an HDMI input, so I figured all would be good. I wanted to make sure I would have one that worked so I bought two of them! The first one arrived, I opened it and got out the manual, and there in the fine print…”the audio signals which are input into the HDMI IN cannot be reproduced on this receiver.” Wow. I had 12 60 watt audio amplifiers at my disposal and still…no sound!

The next day I went back to Shopko and got a blu-ray player there that was on clearance sale for $70. It had a coaxial digital audio output. I remembered that the receiver had a coaxial digital audio input. I was going to be in business.

I haven’t studied the manual for my Sherwood RD-5405 Audio/Video Receiver yet. It’s a computer-controlled gizmo like all these “modern” electronic things are. But I read enough to figure out how to connect it up to some speakers I had laying around, and to my new blu-ray player, and to one of my computer monitors, and I finally got to watch the movie I’d purchased about 2 weeks earlier!

(See the next post for more about some movies I watched.)

Electronics Projects Update

28 July 2014
vacuum tube demo

Vacuum Tube Demonstration Project

Here’s a project I’ve had in mind for quite some time that has finally come together. The inspiration came from the item on the right; an LED lamp made in the style of a camping lantern. “I should put a vacuum tube inside that,” I thought, “you could look at it without worrying about hurting it or yourself.”

At the time I thought I could squeeze all the electronics needed to power the thing inside its bottom battery compartment. But I gave up on that; too cramped. So recently I finally put together a separate box that has all the power supplies needed plus some meters to show you what’s happening.

The display at the top left gives the approximate value of “B+” divided by ten. Below it is the voltage on the plate, also divided by ten. There is a 6,000 ohm resistor between B+ and the plate (or anode). The top right display shows heater voltage, measured directly. And below it is grid voltage, which is actually an inverted copy of the actual grid voltage, which is negative.

Here we have the heater at about 5 volts, the grid at about minus 3.5 volts, and B+ at about 136 volts. The plate is at 96 volts indicating that the tube is conducting about 136 – 96 / 6,000 amps = 6.7 milliamps. This tube is actually rated for 6 volts on the grid, a B+ of about 200 volts and plate currents of up to 30 or 40 milliamps. So I’m not stressing it (or my box) out too much.

Almost all of the materials used in this project are used. The enclosure still has its original panel label on it; a very nice aluminum enclosure. The electronics inside were cool for their day but have almost entirely been replaced with computerized equipment. The power supplies (4 – 48 volt switching supplies plus an 8.5 volt switching supply for the heater) are all used. The digital meters are new, as are most of the control electronics (but purchased from surplus suppliers Jameco and All Electronics).

I was glad to get this one materialized, as it was harder than I thought it would be.

Electronic Percussion

electronic percussion project

Electronic Percussion Project

Here’s a skimpy shot of the beginnings of an electronic percussion instrument. Most of this is new equipment, but not expensive. What you see here includes a stage rack made of black aluminum tubing, one of two BOSS percussion pads which I have had for a long time, and two new KAT pads. Each of the KAT pads has 4 sections, so the whole instrument has 10 striking surfaces in all. All the pads output audio samples of some preselected sounds. The two KAT pads also output MIDI control signals, so I can attach them to a synthesizer and play any sound I want.

Also hiding underneath these pads are used tube clamps from All Electronics. These are an important part of the project as I did not know how I would secure the pads to the stand. The clamps required adapter plates to convert from the hole pattern on the clamps to the hole pattern on the pads. For these I employed 1/8-inch-thick aluminum that was also being sold as used/surplus.

Inspiration

One of my inspirations for building an electronic percussion instrument was Gamelan Sekar Jaya, which I participated in for a year in 1980. There is the backside of I Wayan Suweca, the Balinese teacher who showed us all how to play our parts. At center-left (looking up) is Michael Tenzer, the original mastermind behind this gamelan, who bought the instruments in Bali. He’s now a music professor at the University of British Columbia.

sekar jaya berkeley 1980

Gamelan Sekar Jaya early rehearsal in Berkeley 1980