World War II can be thought of as the first electronic war. Radio technology was firmly established commercially by the late 1930s and poised to make huge contributions to the prosecution of the war on all sides. Radio was rapidly adopted into the battlefield, which led to advancements in miniaturization and ruggedization of previously bulky and fragile vacuum tube gear. Radios were soon being used for everything from coordinating battlefield units to detonating anti-aircraft artillery shells.
But it was not just the battlefields of WWII that benefitted from radio technology. From apartments in Berlin to farmhouses in France, covert agents toiled away over sophisticated transceivers, keying in coded messages and listening for instructions. Spy radios were key clandestine assets, both during the war and later during the Cold War. Continue reading “Hacking When It Counts: Spy Radios”→
A printed copy of the instructions for our example kit
We’ve had two previous articles in this series on turning a personal electronic project into a saleable kit, in which we’ve examined the kit market in a broader context for a new entrant, and gone on to take a look at the process of assembling the hardware required to create a product. We’ve used an NE555 LED flasher as a simple example , from which we’ve gone through the exercise of setting a cost of production and therefore a retail price.
The remaining task required to complete our kit production is to write the documentation that will accompany it. These will be the instructions from which your customers will build the kit, and their success and any other customers they may send your way will hang on their quality. So many otherwise flawless kits get this part of the offering so wrong, so for a kit manufacturer it represents an easy win into which to put some effort. Continue reading “From Project To Kit: Instructions Are Everything”→
When I start up a new project, one that’s going to be worth writing up later on, I find it’s useful to get myself into the right mindset. I’m not a big planner like some people are — sometimes I like to let the project find its own way. But there’s also the real risk of getting lost in the details unless I rein myself in a little bit. I’m not alone in this tendency, of course. In the geek world, this is known as “yak shaving“.
The phrase comes obliquely from a Ren and Stimpy episode, and refers to common phenomenon where to get one thing done you have to first solve another problem. The second problem, of course, involves solving a third, and so on. So through this (potentially long) chain of dependencies, what looks like shaving a yak is obliquely working on cracking some actually relevant problem. Continue reading “Yak Shaving: Hacker Mode Vs Maker Mode”→
In the previous article in this series on making a personal electronic project into a saleable kit, we looked at the broader picture of the kit market for a new entrant, the importance of gauging whether or not your proposed kit has a viable niche and ensuring that it has a good combination of buildability, instructions, and quality. In this article we will look at specifying and pricing the hardware side of a kit, illustrating in detail with an example project. The project we’ve chosen is a simple NE555 LED flasher which we haven’t built and have no intention of assembling into a kit for real, however it provides a handy reference project without the circuit itself having any special considerations which might distract from the job at hand.
If you have an interest in audio there are plenty of opportunities for home construction of hi-fi equipment. You can make yourself an amplifier which will be as good as any available commercially, and plenty of the sources you might plug into it can also come into being on your bench.
There will always be some pieces of hi-fi equipment which while not impossible to make will be very difficult for you to replicate yourself. Either their complexity will render construction too difficult as might be the case with for example a CD player, or as with a moving-coil loudspeaker the quality you could reasonably achieve would struggle match that of the commercial equivalent. It never ceases to astound us what our community of hackers and makers can achieve, but the resources, economies of scale, and engineering expertise available to a large hi-fi manufacturer load the dice in their favour in those cases.
The subject of this article is a piece of extreme high-end esoteric hi-fi that you can replicate yourself, indeed you start on a level playing field with the manufacturers because the engineering challenges involved are the same for them as they are for you. Electrostatic loudspeakers work by the attraction and repulsion of a thin conductive film in an electric field rather than the magnetic attraction and repulsion you’ll find in a moving-coil loudspeaker, and the resulting very low mass driver should be free of undesirable resonances and capable of a significantly lower distortion and flatter frequency response than its magnetic sibling. Continue reading “Electrostatic Loudspeakers: High End HiFi You Can Build Yourself”→
Transistors have come a long way. Like everything else electronic, they’ve become both better and cheaper. According to a recent IEEE article, a transistor cost about $8 in today’s money back in the 1960’s. Consider the Regency TR-1, the first transistor radio from TI and IDEA. In late 1954, the four-transistor device went on sale for $49.95. That doesn’t sound like much until you realize that in 1954, this was equivalent to about $441 (a new car cost about $1,700 and a copy of life magazine cost 20 cents). Even at that price, they sold about 150,000 radios.
Part of the reason the transistors cost so much was that production costs were high. But another reason is that yields were poor. In some cases, 4 out of 5 of the devices were not usable. The transistors were not that good even when they did work. The first transistors were germanium which has high leakage and worse thermal properties than silicon.
Early transistors were subject to damage from soldering, so it was common to use an alligator clip or a specific heat sink clip to prevent heat from reaching the transistor during construction. Some gear even used sockets which also allowed the quick substitution of devices, just like the tubes they replaced.
When the economics of transistors changed, it made a lot of things practical. For example, a common piece of gear used to be a transistor tester, like the Heathkit IT-121 in the video below. If you pulled an $8 part out of a socket, you’d want to test it before you spent more money on a replacement. Of course, if you had a curve tracer, that was even better because you could measure the device parameters which were probably more subject to change than a modern device.
Of course, germanium to silicon is only one improvement made over the years. The FET is a fundamentally different kind of transistor that has many desirable properties and, of course, integrating hundreds or even thousands of transistors on one integrated circuit revolutionized electronics of all types. Transistors got better. Parameters become less variable and yields increased. Maximum frequency rises and power handling capacity increases. Devices just keep getting better. And cheaper.
A Brief History of Transistors
The path from vacuum tube to the Regency TR-1 was a twisted one. Everyone knew the disadvantages of tubes: fragile, power hungry, and physically large, although smaller and lower-power tubes would start to appear towards the end of their reign. In 1925 a Canadian physicist patented a FET but failed to publicize it. Beyond that, mass production of semiconductor material was unknown at the time. A German inventor patented a similar device in 1934 that didn’t take off, either.
Replica of the First Transistor
Bell labs researchers worked with germanium and actually understood how to make “point contact” transistors and FETs in 1947. However, Bell’s lawyers found the earlier patents and elected to pursue the conventional transistor patent that would lead to the inventors (John Bardeen, Walter Brattain, and William Shockley) winning the Nobel prize in 1956.
Two Germans working for a Westinghouse subsidiary in Paris independently developed a point contact transistor in 1948. It would be 1954 before silicon transistors became practical. The MOSFET didn’t appear until 1959.
Of course, even these major milestones are subject to incremental improvements. The V channel for MOSFETs, for example, opened the door for FETs to be true power devices, able to switch currents required for motors and other high current devices.
VCF West is happening this Saturday and Sunday at the Computer History Museum in Mountain View, CA. This on of our favorite events; a celebration of the hardware that paved the way for our modern world. VCF attracts an impressive amount of rare and interesting computers and other technology items. That hardware doesn’t make it to the festival on its own. The people at VCF — exhibitors, speakers, attendees, etc — are themselves an incredible collection of stories from salvage and restoration to the inside story on the teams that made the computers in the first place. Check out some of Brian Benchoff’s coverage of VCF East earlier this year.
I ran into Vintage Computer Federation President Evan Koblentz ten days ago and he shared an interesting anecdote I think you’ll enjoy. Bil Herd was a featured speaker at VCF East a few years back. He was the Senior Design Engineer behind the Commodore C128 — obviously a fascinating person to headline the event. The year after Bil spoke at the festival, Evan as surprised to run into him wandering around the event again. Bil didn’t just want to speak, he wanted to see all the cool stuff and has attended, spoken, and conducted workshops at several of the festivals since.
Who will show up this year is anyone’s guess. But we know this event is incredible and you will be amazed at who you run into. It is important to recognize where our technology comes from, to celebrate those who made it happen, and to encourage young people to start on the path to becoming a computer engineering wizard. For all of these reasons we are happy to be sponsoring VCF West. On the inside cover of every festival program you’ll find this epic art by our Illustrator, Joe Kim. You can also click the image on the right to embiggen.
Joshua Vasquez will on hand for Hackaday at VCF West. He’s looking for the best bits to feature on our front page. If you want get a hold of him to show off your wares, or to grab some excellent Hackaday stickers, hit him up on Hackaday.io.
