Cesium Clock Teardown, Or Quantum Physics Playground

March 25, 2020 by 20 Comments

Half the fun of getting vintage test equipment is getting to open it up. Maybe that’s even more than half of the fun. [CuriousMarc] got an HP 5061A Cesium clock, a somewhat famous instrument as the model that attempted to prove the theory of relativity. The reason? The clock was really the first that could easily be moved around, including being put on an airplane. You can watch the video below.

According to the video, you can simplify special relativity to saying that time slows down if you go fast — that is known as time dilation. General relativity indicates that time slows down with increasing gravity. Therefore, using airborne Cesium clocks, you could fly a clock in circles high up or fly at high speeds and check Einstein’s predictions.
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Electromagnetic Field 2020 Cancelled

March 25, 2020 by 4 Comments

It’s the news we were all expecting but not looking forward to hearing: this summer’s EMF Camp which was to be held at the end of July in Herefordshire, UK, has been cancelled. This is of course due to the ongoing public health measures surrounding the COVID-19 virus pandemic. With the country on lockdown for the forseeable future, this is a responsible decision for a gathering the size of EMF which hosted around 2,500 attendees in 2018.

Existing ticket holders will be refunded, and will be guaranteed a ticket to the next event in 2022. According to the announcement, EMF is in the red to the tune of at least £25,000 ($29,523) because of non-refundable payments associated with booking the event, something to remember in two years time when faced with the choice of a normal ticket or a supporters ticket.

Work on starting conference badge production has been halted, but development continues apace and will not go to waste as it will form the basis of the 2022 item. This will make them the event badge team with the earliest preparation ever, and from what we saw when we had a brief look at an early prototype last year it should be a badge worth waiting for.

We’re sure all readers will understand the gravity of the situation, and that the EMF team have taken an appropriate response to what is an extraordinary series of events. Organising a hacker camp is a tough job at the best of times, and this must have been particularly hard on them. We thank them for their work on our behalf at previous events and in preparing for this aborted one, and we look forward to the next EMF Camp in 2022.

GSM Module Does More Than Advertised

March 25, 2020 by 13 Comments

For many projects, a WiFi connection is overkill, too complicated, or too far away to work properly. Even though it’s relatively ubiquitous, sometimes the best choice for getting data to or from the real world is a connection to the cellular network, which can be done with the M590 module for about a dollar each. For that price, lots of people have had the opportunity to explore the module itself, and [marcrbarker] shows some of the extra, unadvertised, features it has.

Acting as a GSM module that can send and receive SMS messages is just the tip of the iceberg for this tiny device which we saw once before for a DIY GPS tracker. With a USB TTL serial data module, a lot more is on the table including answering voice calls and responding with DTMF tones, operate as a dial-up modem, connect with TCP, and even has some FTP capabilities. [marcrbarker] also suggests that it could do “call pranking” where it can send signals without being charged for a call.

There are a lot of details on the project site about all of this newfound functionality, and it reminds us of a time when it was discovered that not only was the ESP8266 a cheap WiFi module, but it could also run custom programs on its own. While the M590 probably can’t do all of that, it does seem to have a lot more locked away than most of us had thought before.

Geofence Warrant Sends Bicyclist’s Privacy Over The Handlebars

March 25, 2020 by 98 Comments

About a year ago, Zachary McCoy took a bike ride around his neighborhood in Gainesville, Florida. It may have been forgettable to him, but not to history. Because McCoy used an app to track his mileage, the route was forever etched in the Google-verse and attached to his name.

On the day of this ill-fated bike ride, McCoy passed a certain neighbor’s house three times. While this normally wouldn’t raise alarm, the neighbor happened to be the victim of a burglary that day, and had thousands of dollars worth of jewelry stolen. The Gainesville police had zero leads after a four-day investigation, so they went to the county to get a geofence warrant. Thanks to all the location data McCoy had willingly generated, he became the prime suspect.

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Thunder Pack Is A Bolt Of Lightning For Wearables

March 25, 2020 by 19 Comments

Do you need portable power that packs a punch? Sure you do, especially if you want to light up the night by mummifying yourself with a ton of LED strips. You aren’t limited to that, of course, but it’s what we pictured when we read about [Jeremy]’s Thunder Pack. With four PWM channels at 2.3 A each, why not go nuts? [Jeremy] has already proven the Thunder Pack out by putting it through its paces all week at Burning Man.

Click to embiggen!

After a few iterations, [Jeremy] has landed on the STM32 microcontroller family and is currently working to upgrade to one with enough flash memory to run CircuitPython.

The original version was designed to run on a single 18650 cell, but [Jeremy] now has three boards that support similar but smaller rechargeable cells for projects that don’t need quite as much power.

We love how small and powerful this is, and the dongle hole is a great touch because it opens up options for building it into a wearable. [Jeremy] made a fantastic pinout diagram and has a ton of code examples in the repo. If you want to wade into the waters of wearables, let whimsical wearables wizard [Angela Sheehan] walk you through the waves.

Ventilators 101: What They Do And How They Work

March 25, 2020 by 88 Comments

Treating the most serious cases of COVID-19 calls for the use of ventilators. We’ve all heard this, and also that there is a shortage of these devices. But there is not one single type of ventilator, and that type of machine is not the only option when it comes to assisted breathing being used in treatment. Information is power and having better grasp on this topic will help us all better understand the situation.

We recently wrote about a Facebook group focused on open source ventilators and other technology that could assist in the COVID-19 pandemic. There was an outpouring of support, and while the community is great when it comes to building things, it’s clear we all need more information about the problems doctors are currently dealing with, and how existing equipment was designed to address them.

It’s a long and complicated topic, though, so go get what’s left of your quarantine snacks and let’s dig in.

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Ken Shirriff Unfolds A Nuclear Missile Guidance Computer With Impressive Memory

March 25, 2020 by 13 Comments

Longtime followers of [Ken Shirriff’s] work are accustomed to say asking “Where does he get such wonderful toys?”. This time around he’s laid bare the guidance computer from a Titan missile. To be specific, this is the computer that would have been found in the Titan II, an intercontinental ballistic missile that you may remember as a key part of the plot of the classic film WarGames. Yeah, those siloed nukes.

Amazingly these computers were composed of all digital logic, no centralized controller chip in this baby. That explains the need for the seven circuit boards which host a legion of logic chips, all slotting into a backplane.

But it’s not the logic that’s mind-blowing, it’s the memory. Those dark rectangles on almost every board in the image at the top of the article are impressively-dense patches of magnetic core memory. That fanout is one of two core memory modules that are found in this computer. With twelve plates per module (each hosting two bits) plus a parity bit on an additional plate, words were composed of 25-bits and the computer’s two memory modules could store a total of 16k words.

This is 1970’s tech and it’s incredible to think that when connected to the accelerometers and gyros that made up the IMU this could use dead reckoning to travel to the other side of the globe. As always, [Ken] has done an incredible job of walking through all parts of the hardware during his teardown. He even includes the contextual elements of his analysis by sharing details of this moment in history near the end of his article.

If you want to geek out a little bit more about memory storage of yore, you can get a handle on core, drum, delay lines, and more in Al Williams’ primer.