Author: Dan Maloney

3368 Articles

Retrotechtacular: Measuring TV Audiences With The “Poll-O-Meter”

March 12, 2022 by 21 Comments

It may come as a shock to some, but TV used to be a big deal — a very big deal. Sitting down in front of the glowing tube for an evening’s entertainment was pretty much all one had to do after work, and while taking in this content was perhaps not that great for us, it was a goldmine for anyone with the ability to monetize it. And monetize it they did, “they” being the advertisers and marketers who saw the potential of the new medium as it ramped up in early 1950s America.

They faced a bit of a problem, though: proving to their customers exactly how many people they were reaching with their ads. The 1956 film below shows one attempt to answer that question with technology, rather than guesswork. The film features the “Poll-O-Meter System,” a mobile electronic tuning recorder built by the Calbest Electronics Company. Not a lot of technical detail is offered in the film, which appears aimed more at the advertising types, but from a shot of the Poll-O-Meter front panel (at 4:12) and a look at its comically outsized rooftop antenna (12:27), it seems safe to assume that it worked by receiving emissions from the TV set’s local oscillator, which would leak a signal from the TV antenna — perhaps similar to the approach used by the UK’s TV locator vans.

The Poll-O-Meter seems to have supported seven channels; even though there were twelve channels back in the day, licenses were rarely granted for stations on adjacent channels in a given market, so getting a hit on the “2-3” channel would have to be considered in the context of the local market. The Poll-O-Meter had a charming, homebrew look to it, right down to the hand-painted logos and panel lettering. Each channel had an electromechanical totalizing counter, plus a patch panel that looks like it could be used to connect different counters to different channels. There even appears to be a way to subtract counts from a channel, although why that would be necessary is unclear. The whole thing lived in the back of a 1954 VW van, and was driven around neighborhoods turning heads and gathering data about what channels were being watched “without enlisting aid or cooperation of … users.” Or, you know, their consent.

It was a different time, though, which is abundantly clear from watching this film, as well as the bonus ad for Westinghouse TVs at the end. The Poll-O-Meter seems a little silly now, but don’t judge 1956 too hard — after all, our world is regularly prowled by equally intrusive and consent-free Google Street View cars. Still, it’s an interesting glimpse into how one outfit tried to hang a price tag on the eyeballs that were silently taking in the “Vast Wasteland.”

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Boat Anchor Twins Get A Little Digital Help Staying On Frequency

March 11, 2022 by 9 Comments

In the ham radio trade, gear such as the old Drake units [Dr. Scott M. Baker] has in his radio shack are often referred to as “boat anchors.” It refers to big, heavy radios that were perhaps a bit overengineered compared to the state of the art at the time they were designed, and it’s actually a shame that the name has taken on something of a pejorative connotation, since some of this gear is rock solid half a century or more after it was built.

But older gear is often harder to use, at least compared to the newer radios with microcontrollers and more stable oscillators inside. To make his 1970s-era Drake “Twins” setup of separate but linked receiver and transmitter a little more fun to use, [Scott] came up with this neat Raspberry Pi-based DDS-VFO project to keep his boat anchors afloat. Compared to the original mechanically tuned variable frequency oscillator in the Drake receiver, the direct-digital synthesis method promises more stability, meaning less knob-nudging to stay on frequency.

The hardware used for the DDS-VFO is actually pretty simple — just a Raspberry Pi Zero W driving an AD9850-based signal-generator module. Sending the signal to the Twins was another matter. That was done by tapping into the injection cable linking both units, which meant a few circuit complications to deal with signal attenuation. [Scott] also added amenities like a digital frequency display, optical encoder with crank-style knob to change frequency, and a host of Cherry MX keyswitches for quick access to different features.

From the look of the video below, the Twins are now rock-solid and a lot easier to use. This project is loosely based on a recent panadapter project [Scott] undertook for the receiver side of the Twins.

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Extreme Espresso, Part 2: An Inductive Water Level Sensor

March 8, 2022 by 27 Comments

[Mark Smith] must really, really like his coffee, at least judging by how much effort he’s put into tricking out his espresso machine.

This inductive water tank sensor is part of a series of innovations [Mark] has added to his high-end Rancilio Silvia machine — we assume there are those that would quibble with that characterization, but 800 bucks is a lot to spend for a coffee maker in our books. We recently featured a host of mods he made to the machine as part of the “Espresso Connect” project, which includes a cool Nixie tube bar graph to indicate the water level in the machine. That display is driven by this sensor, the details of which [Mark] has now shared. The sensor straddles the wall of the 1.7-liter water tank, so no penetrations are needed. Inside the tanks is a track that guides a copper and PETG float that’s sealed with food-safe epoxy resin.

Directly adjacent to the float track on the outside of the tank is a long PCB with a couple of long, sinuous traces. These connect to an LX3302A inductive sensor IC, which reads the position of the copper slug inside the float. That simplifies the process greatly; [Mark] goes into great detail about the design and calibration of the sensor board, as well as hooking it into the Raspberry Pi Zero that lies at the heart of “Espresso Connect’. Altogether, the mods make for a precisely measured dose of espresso, as seen in the video below.

We’d say this was maybe a bit far to go for the perfect cup of coffee, but we sure respect the effort. And we think this inductive sensor method has a lot of non-caffeinated applications that probably bear exploration.

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Metal 3D Printing Hack Chat

March 7, 2022 by 1 Comment

Join us on Wednesday, March 9 at noon Pacific for the Metal 3D Printing Hack Chat with Agustin Cruz!

3D printing has been an enabling technology, and the ability to create parts that never existed anywhere before has been a real game-changer. But the cheap and readily accessible FDM and SLA printers we’ve come to depend on are not without their drawbacks, chief among which is that they only make plastic parts. Wouldn’t it be great if we home-gamers had the ability to print metal parts just like they do in industry? Agustin Cruz thinks so, and he’s been hard at work on an electron-beam sintering printer to make that dream come true. Dealing with the technical challenges of such a printer hasn’t been easy, but then again, squeezing out melted plastic wasn’t easy at first either.

join-hack-chatAgustin has agreed to take a little time out of his project to talk to us about his progress, and to share what he has learned about electron-beam printing. Along the way, we’ll talk about metal printing in general, and perhaps even take a look at where the whole field is going and how — and when — it’ll penetrate the hobby printing market.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 9 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.
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Hackaday Links: March 6, 2022

March 6, 2022 by 12 Comments

As if the war in Ukraine weren’t bad enough right here on Earth, it threatens knock-on effects that could be felt as far away as Mars. One victim of the deteriorating relationships between nations is the next phase of the ExoMars project, a joint ESA-Roscosmos mission that includes the Rosalind Franklin rover. The long-delayed mission was most recently set for launch in October 2022, but the ESA says that hitting the narrow launch window is now “very unlikely.” That’s a shame, since the orbital dynamics of Earth and Mars will mean that it’ll be 2024 before another Hohmann Transfer window opens. There are also going to be repercussions throughout the launch industry due to Russia pulling the Soyuz launch team out of the ESA’s spaceport in Guiana. And things have to be mighty tense aboard the ISS right about now, since the station requires periodic orbital boosting with Russian Progress rockets.

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Retro Serial Terminal Uses Modern Chips To Get CP/M Machine Talking

March 6, 2022 by 26 Comments

The hobbyists of the early days of the home computer era worked wonders with the comparatively primitive chips of the day, and what couldn’t be accomplished with a Z80 or a 6502 was often relegated to complex designs based on logic chips and discrete components. One wonders what these hackers could have accomplished with the modern components we take for granted.

Perhaps it would be something like this minimal serial terminal for the current crop of homebrew retrocomputers. The board is by [Augusto Baffa] and is used in his Baffa-2 homebrew microcomputer, an RC2014-esque Z80 machine that runs CP/M. This terminal board is one of many peripheral boards that plug into the Baffa-2’s backplane, but it’s one of the few that seems to have taken the shortcut of using modern microcontrollers to get its job done. The board sports a pair of ATmega328s; one handles serial communication with the Baffa-2 backplane, while the other takes care of running the VGA interface. The card also has a PS/2 keyboard interface, and supports VT-100 ANSI escapes. The video below shows it in action with a 17″ LCD monitor in the old 4:3 aspect ratio.

We like the way this terminal card gets the job done simply and easily, and we really like the look of the Baffa-2 itself. We also spied an IMSAI 8080 and an Altair 8800 in the background of the video. We’d love to know more about those.

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Minecraft furnace IRL

Replica Minecraft Furnace Actually Powers The Game

March 5, 2022 by 3 Comments

Let’s face it, we all need a little distraction sometimes, especially lately. And for our money, there’s no better way to put your brain in park than to start up a Minecraft world and get to digging. The simple graphics, the open world, and the lack of agenda other than to find resources and build things are all very soothing.

But play the game long enough and you’re bound to think about what it would be like if the game world crossed over into the real world. The ironically named [Michael Pick] did just that when he managed to craft a real Minecraft furnace that can actually power the game. Of course, there are some liberties taken with the in-game crafting recipe for a furnace, which is understandable for a game that allows you to punch trees with a bare fist to cut them down.

Rather than using eight blocks of cobblestone to build his furnace, [Michael] made a wooden shell for a commercial folding camp stove. Insulated from the shell by a little cement board, the furnace looks pretty true to the in-game item. To generate the electricity needed to run the game, he used a pair of thermoelectric camping generators. With the stove filled with wood — presumably un-punched — the generators put out enough juice to at least partially charge a battery bank, which was then used to power a Raspberry Pi and 7″ monitor. His goal was to get enough power from the furnace to do a speed run in the game and find three diamonds to build a diamond pickaxe. Honestly, we’re jealous — our first diamonds never come that easy.

We’ve seen other Minecraft-IRL crossovers before. Fancy a ride in a minecart? We’ve got that covered. Or maybe you’d rather control a desk lamp from within the game? That’s a thing, too.

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