Gas station without pumps

2015 October 8

Heathkit moves to Santa Cruz

Filed under: Uncategorized — gasstationwithoutpumps @ 14:40

According to a Hackaday post, Heathkit: Live, Die, Repeat,

This morning, the president of Heathkit sent a message to the ‘Heathkit Insiders’ email group explaining the goings on and new happenings:

We’ve designed and developed a wide range of entirely new kit products. We authored the manuals for these kits, complete with the beautiful line art you rely on, preserving and respecting our iconic historic Heathkit style. We developed many new inventions and filed patents on them. We relocated Heathkit, and set up a factory, and a warehouse, and offices, in Santa Cruz, California, near Silicon Valley. We built the back office infrastructure, vendor and supply chain relationships, systems, procedures, operations methods, and well-thought-out corporate structure that a manufacturing company needs to support its customers, to allow us to scale instantly the day we resume major kit sales. All this effort enables us to introduce a fleet of new kits and helps ensure Heathkit can grow, prosper, and continue to bring you great new products for a very long time.

If this news is real, it is very exciting. Heathkit was one of my favorite companies as a child (see Thanks, Dad), and I have fond memories of building some of their kits.  I can’t think of a better place for them to be than here in Santa Cruz.

Unfortunately, the kit that they seem to basing their hopes on, the Explorer Jr AM radio kit, is rather overpriced at $150.  It will only sell to nostalgia fans, which is probably not a big enough base for reviving the company.  What they need to do is to make kits in the same price range as Velleman, but with Heathkit-quality manuals.

2012 April 20

Make: Kit Reviews | The Ultimate Kit Guide

About a month ago, Make magazine released their reviews of various kits, Make: Kit Reviews | The Ultimate Kit Guide.  I have been a big fan of kits as a way to get kids into the habit of building things and knowing how they are put together.  They provide an intermediate point between ready-made consumer goods and hand-made artisanal goods.

I’ve talked before about my fondness for Heathkit electronics kits when I was growing up (Thanks, Dad!) and about how I was glad to see that they were finally back in the kit business. The kit issue of Make has a number of cool things in it ranging from the $3 Learn-to-Solder badge to $800 model submarines, $1000 mini CNC milling machines, $1300 3D printers, and $863 wood-fired hot tubs.  Although there are few kits in the issue that I really want, it is cool to see just how much is available in kit form these days.  Some are old-school kits (tube amplifiers! crystal radios! Nixie tubes!) and some are very modern (RFID breakout boards, quadracopters, drone planes).

My son has made a number of kits over the years (like the Velleman MK150 shaking dice kit or the K5300 Stroboscope with a xenon tube), and he is now moderately competent with soldering iron, solder sucker, diagonal cutters, and long nose pliers.  I suppose I should get him doing some surface-mount soldering, as my fine-motor control is a little shaky for 1mm × 2mm capacitors and 0.05″ pitch leads on ICs.  (Yes, I’ve seen instructions for making solder reflow ovens out of toaster ovens, and doing soldering with a skillet, but I’m not yet convinced that those are functional enough to be worth the investment in time and fried parts.)

Leads torn on pressure sensor.

The point about SMD soldering comes up this week because the pressure sensor superglued to the inside of the dry box for the underwater vehicle had its leads torn apart. This is probably my fault, since I had suggested the idea of supergluing the pressure sensor to the inside of the dry box without giving any consideration to the forces on the tiny little leads of the pressure sensor.

I had some spare sensor boards, but I had to order more pressure sensors from Digikey and assemble a new board for them.  This weekend, they’ll drill yet another hole in the drybox and glue the replacement pressure sensor in place, but this time there will be a couple of pieces of plastic glued to the PC board (about 4.8mm thick, to match the thickness of the pressure sensor body) also glued to the inside of the dry box, so that unplugging the cables will not put strain on the tiny wires of the pressure gauge.

The new hole will make the 6th penetration of the dry box.  Somewhat amazingly, none of these penetrations have leaked, although we have had problems with the underwater connector that they designed for the motor wires.  We’re hoping that problem will be fixed this weekend.

2012 February 20

Heathkit is back in the kit business

Filed under: Uncategorized — gasstationwithoutpumps @ 19:52
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Last year, in my Thanks, Dad post, I mentioned how much Heathkits had meant to me growing up, and how I missed the combination of detailed instructions and how-things-work of their manuals in more recent kits.

Heathkit is now back in the kit business. They have started with only one kit, a Garage Parking Assistant,which is of little use to me as I have no car (nor any room in my garage if I had one).

They plan to add more kits in four categories:

The kits will almost certainly be more expensive than buying already built versions of the products, since it is much cheaper to integrate and assemble things in a factory than to count and package parts that can be hand assembled.  The value of electronic kit building nowadays is more in learning and sense of accomplishment than it is in saving money.

I understand that the audio and amateur radio kits will be based around vacuum-tube technology, which is not so easy to get commercially, and for which kit building is competitive with commercial assembly.

I welcome Heathkit back to the kit-making business, and I hope that they do well.

(I found out about Heathkit’s return to kits from the special kit issue of Make Magazine—an issue with many fine kits in it, though some of the most attractive ones are beyond what I’m willing to spend on a toy at the moment.)

2011 February 9

Thanks, Dad

My Dad turns 85 today, so I thought this would be a good time to thank him for all the things he did for me.  I’m not talking of the routine things, like keeping us fed, housed, and educated, but the special things that made him unique.

One particular thing I’d like to thank him for  is for introducing me to science and engineering as a child.  Most people have the impression that kids learn math and science in the schools, and that improving schools is key to creating more scientists and engineers. Personally, I have some doubts about this—I think that for decades US schools have done little to train future scientists and engineers, and that our country has been relying on an apprenticeship system, in which scientists and engineers train their children, at least until they go off to college. That is largely how it worked for me and for many of my colleagues.

I learned about logarithms and complex numbers from my dad, long before I saw the subjects in school. I learned how to use a slide rule, and why it worked (he also bought me my first calculator, back when that was an investment comparable to getting a top-of-the-line laptop today). I learned Ohm’s Law and about impedances and Wheatstone bridges from him—I never had a formal circuits course in college, though I ended up teaching VLSI design as a EE professor for 4 years and as a computer engineering professor for another 14 years.

I remember one joke Dad was fond of, which only works in German.  One goes through a the names of a number of cities (X) and asks where one can find the X Brücke, the answer being “in X”, ending up with the Wien Brücke, which is an electrical bridge with RC elements on two of legs of the bridge, not a bridge in Vienna.  The circuit has a strong frequency dependence, and a variant of it (the Wien-Robinson-Brücke) is the core of the Wien bridge oscillator that was Hewlett-Packard’s first product. (Although I learned German in high school, my Dad was helpful in keeping me interested in it and in improving my accent.  I have since forgotten a lot of grammar and the genders of many of the nouns, but I don’t have much of an American accent.)

My dad also provided us with lots of science toys, often in the form of kits or surplus equipment.  I particularly remember building and playing with Heathkits: a vacuum-tube voltmeter, a grid-dip meter, and (the biggest project) an oscilloscope.  I recently did some image searches on the web to try to identify the model of oscilloscope we had. As best I can tell, it was an OM-2:

I have recently bought myself a used oscilloscope and signal generator on ebay, for not much more than the original Heathkit cost, but this is a Kikusui COS-5060 60MHz, dual trace scope with fancy triggering options, not a bare bones 2MHz scope.  Even analog electronics have gotten cheaper over the years, not just digital. I plan to teach my son how to use these instruments, and hope he gets as much out of it as I got out of the Heathkit.  Probably not, though, since he won’t be building it, and it doesn’t come with detailed explanations of how it works.

Kikusui COS-5060 oscilloscope and Clarke-Hess model 744 function generator, bought on e-bay for $102.50 and $36.76 respectively (plus rather expensive shipping).

The grid-dip meter was a kind of cool toy:  it is basically just a one-tube radio frequency oscillator, but when it is placed near an inductor that is part of another resonant circuit, you get a dip in the current in the grid of the tube when the frequencies match.  Why is that cool? Because you can mess up the images on TV sets by using the broadcast frequencies, the IF frequencies of the receiver circuits, or the frequencies of the raster scan. I believe I had a KnightKit G30 grid-dip meter:

I found that someone has scanned in the whole assembly manual for the Knight G-30.

Schematic for Knight G-30 grid dip meter.

The schematic for the Knight G-30 grid dip meter. Note the simple one-tube oscillator circuit. Image shrunk from scanned copy at

I’m not sure what model of vacuum-tube volt meter we had.  The closest match I can find to my memory is the V-7, but it doesn’t match my memory exactly.  I seem to remember only banana-plug inputs.  Perhaps some historian of Heathkits could help me figure out which model we had.  It was bought before the oscilloscope and the grid-dip meter, I believe, if that helps narrow the time period.

My Dad, my older brother, and I spent a lot of time building the Heathkits, but that wasn’t all the engineering education I got.  I can remember my Dad bringing home a coil winder from work, and we spent some time making our own iron-core transformers (though I forget now why we were making them).

I don't remember exactly what coil winder my dad brought home from work, but it looked a lot like this picture of a Morris coil winder from

It wasn’t just in electronics that my Dad supported my education.  He also bought the family a beautiful old microscope, which he recently shipped to me for my son to use. Unfortunately, there were some heavy things in the same box, and mirror got broken.  Does anyone know where I can get a replacement mirror for an Ernst Leitz Wetzlar microscope (from about 1930)?

Ernst Leitz Wetzlar microscope

This is the beautiful old microscope that I used in high school. I would like to restore the mirror that was damaged in shipping.

Since it is now science fair season (I judged one school fair last week and will judge another one this week, though the County Science Fair is still a month away), I would be remiss in not mentioning how Dad supported us through our science fairs.  I can only remember three projects now, two of mine and one of my brothers, but I’m sure there were others based on things we read in the Amateur Scientist columns of  Scientific American.  I read Amateur Scientist and Mathematical Games every month, even when the rest of the magazine was not interesting to me.  I now have the full collection of Amateur Scientist on CD-ROM, but reading it on-screen does not have the same appeal as turning to the back of the glossy magazine, and I have not done more than glance at the columns on the CD-ROM.  I tried re-subscribing to Scientific American a few years ago, but it had become like People in science, and I found it a complete waste of time.  I’ve done better with Make magazine and IEEE Spectrum.

Two of the science fair projects I remember could not have been the same year, because both involved the same piece of equipment: a cheap portable record player, which we used just as a constant speed motor.

  • My older brother hooked up a 3′ or 4′ wooden arm to the turntable, with wheel at the end, to get a wheel that moved at constant speed along a circular track.  He then piled sand on the track and experimented with making road corrugations.  I forget what the independent variables were—probably speed and weight, but the apparatus did make cool corrugations in the sand track.
  • I used the same turntable with a cardboard and aluminum foil disk and some stranded wire for brushes to make a low-frequency square-wave AC signal from a battery.  The power then went to two carbon electrodes (scavenged from dead batteries) in salt water, and I measured the hydrogen and oxygen released by DC and AC currents in some glass funnels with long tubes.  Unfortunately, the slowest speed of the turntable (33 1/3 rpm) produced 0.555 Hz, which was still too high a frequency to get any electrolysis, so I ended up using a DPDT switch and manually reversing the current about every 10 seconds (0.05 Hz).

The other project I remember was one on vortex rings (the fancy name for smoke rings).  We drilled a 1″ hole in the bottom of a coffee can, and tapped the lid to get very neat smoke rings.  The smoke was generated by burning tobacco in a corncob pipe.  We rigged a Raleigh bike pump to suck air instead of pushing it (just reversing the leather cup washer on the piston), so no one had to directly breathe the smoke.  I remember that the clear tubing got really disgusting buildups of tar—this project may have contributed to my never smoking, despite the coolness of smoke rings.  Nowadays one can buy a Zero Blaster with non-toxic smoke or an Airzooka to get really big vortex rings, but in those days there was no off-the-shelf solution.  I don’t remember what I did with the smoke rings now, though I do remember that I had made a cardboard shield with a Lucite window to view the smoke rings in still air.

As an engineering professor, I often find myself saying to students things my Dad said to me.  One of his most popular responses when asked “what would happen if … ?” questions was “Try it and see.”  I find myself telling that to senior design students who have been dragging their feet on their projects, uncertain how to design something and wanting someone to hand them a solution.

Besides science and engineering, my Dad taught me many things that are still important to me today.  For example, he taught me to ride a bicycle and do simple maintenance.  My bicycle is now my main means of transportation, and I ride a couple of thousand miles a year commuting to work.  Dad and I have done a couple of self-contained (camping) long-distance tours together: in 1992 from his house to the League of American Wheelmen rally in River Falls, Minnesota, together with members of his bicycling club and in 1994 from my house to North Hollywood, 466 miles down the California coast, together with my nephew.  We also attended a League of American Wheelmen Rally in Flagstaff, Arizona in 1988 that included a supported ride to Sunset Crater and Grand Canyon.

I couldn’t remember when the Arizona ride was and the League of American Bicyclists has a terrible web site with almost no historical records. After wasting a lot of time searching the web without finding anything useful, I switched to the older technique of looking at paper records.  I found my log book for the solo ride I took in 1991 from the Rally in Olympia, Washington back to Santa Cruz, which was my first self-supported tour, and the log book mentioned that I had done the Arizona ride “some time ago”.  Luckily, I had paper copies of the L.A.B. and L.A.W. newsletters back to 1987, so I found out when the Arizona Rally had been fairly quickly.

Although Dad and I have shared a love of cycling, I’ve never acquired his love of swimming.  I learned how to swim as a child, but never really enjoyed it.  Part of the problem was that I was a very skinny child with almost no subcutaneous fat, so I got seriously chilled after just a little while in the water.  Now, I’m verging on overweight, so perhaps I should try swimming again.  Of course, the ocean here is far too cold to swim in without a wetsuit, and the City pool has been closed due to budget cuts for over a year.  I don’t think I want to pay the high prices the University charges faculty to use their pool, so it is unlikely that I’ll be taking up swimming any time soon.

Disclaimer: I received no compensation for plugging any of the products depicted on this page. If someone wants to send me free electronic test equipment or a coil winder, let me know.

2010 November 13

Why no digital oscilloscope for Macbooks and iPads?

Filed under: Uncategorized — gasstationwithoutpumps @ 00:08
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This summer I was playing a little with electronic hardware (something I’ve not done much since I left computer engineering as a field) and was wishing I had an oscilloscope at home.  I don’t want one of the huge old CRT oscilloscopes, like the Heathkit that my brother and I assembled as kids (I don’t remember the model number, but looking in the Heathkit Virtual Museum, I think it was the OM-11).  Neither do I want one of the little pocket oscilloscopes that look like graphing calculators, with the same sort of low-quality screens and fiddly interfaces.

What I’d like is a USB device that handles the analog part of a digital storage scope that plugs into my laptop and uses the laptop for storing, processing, and displaying the signals.  There are dozens of USB oscilloscopes on the market, but so far as I could tell, none of them had software that would run under Mac OS X.  I found this a little surprising, as the Mac OS X machines are much more popular with computer scientists and bioinformaticians than Windows machines are, and I thought that computer engineers would have established a market for USB scopes for Macbooks.  It is true that most of the EE students and faculty I know who would be competent to design the analog electronics for a USB scope do not have the programming ability to design multi-platform software.  I guess that the small companies that sell digital scopes don’t have the resources to hire two engineers (one to design the hardware, another to design the software), and so make do with half-assed designs that only run on one operating system.

I think that there is a market out there for USB scopes that can work with any of the common laptop platforms (Windows, Mac OS X, and Linux).  In fact, an all-software solution that works with several of the existing USB hardware devices would be ideal.  This seems to me like a great project for a computer engineering student who enjoys writing device drivers and working out communications protocols with hardware that was probably designed with no attention at all to the needs of software engineers.

If someone is looking for a hardware project, I think that the iPad looks like a great device to be the screen of an oscilloscope.  This would require a digital storage scope that is not a USB device but uses the weird iPad/iPhone/iPod connector.  It would probably need its own rechargeable battery, as the iPad is not going to provide much power.  I don’t currently own an iPad, and have no plans to get one, but if someone came out with a great oscilloscope based on it, I might get one just for that app.

UPDATE: December 2012

I bought a USB oscilloscope that does work with Mac OS X (the BitScope Pocket Analyzer).  Screenshots and comment at FET threshold tests with Bitscope.

UPDATE: January 2017

I bought a much better USB oscilloscope, the Analog Discovery 2 by Digilent, which works with Mac, Windows, and Linux computers. Both the hardware and the software are much better than the BitScope (which has not improved much in the intervening 4 years). Digilent has an excellent academic discount program also. I have a series of posts using the Analog Discovery 2.

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