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Drink Lots Of Beer To Raise Your Monopole

January 26, 2018 by 19 Comments

When we published a piece about an ADS-B antenna using a Coke can as a groundplane, Hackaday reader [2ftg] got in contact with us about something with a bit more… stature.

A monopole groundplane antenna is a single vertical conductor mounted on an insulator and rising up above a conductive groundplane. In radio terms the groundplane is supposed to look as something of a mirror, to provide a reflection of what would come from the other half of a dipole were there to be two conductors. You can use anything conductive as your monopole, a piece of wire, (in radio amateur humour) a piece of wet string, or even beer cans. “Beer cans?” you ask incredulously, expecting this to be another joke. Yes, beer cans, and [2ftg] has been good enough to supply us with a few examples. The first is a 57-foot stack of them welded together in the 1950s for use on the 80 metre band ( we suspect steel cans may have been more common than aluminum back then), the second is a more modest erection for the 2 metre band, and the final one consists of photographs only of an HF version that looks a little wavy and whose cans are a little less beery.

The reporting in the 1950s piece is rather cheesy, but does give a reasonable description of it requiring welding rods as reinforcement. It also gives evidence of the antenna’s effectiveness, showing that it could work the world. Hardly surprising, given that a decent monopole is a decent monopole no matter how many pints of ale you have dispatched in its making.

The Coke can ADSB can be seen in all its glory here, and if all this amateur radio business sounds interesting, here’s an introduction.

Beer cans picture: Visitor7 [CC BY-SA 3.0].

Search For Military Satellite Finds One NASA Lost Instead

January 25, 2018 by 26 Comments

[Scott Tilley] was searching for radio signals from the Air Force’s top-secret ZUMA satellite. He found something that is — we think — much more interesting. He found NASA’s lost satellite called IMAGE. You are probably wondering why it is interesting that someone listening for one satellite found another one. You see, NASA declared IMAGE dead in 2005. It went silent unexpectedly and did not complete its mission to image the magnetosphere.

NASA did a failure review and concluded that in all likelihood a single event upset caused a power controller to trip. A single event upset, or SEU, is a radiation event and should have been automatically recovered. However, there was a design flaw that failed to report certain types of power controller failures, including this one.

The report mentioned that it might be possible to reset the controller at a specific time in 2007, but given that NASA thought the satellite was out of commission that either never occurred or didn’t work. However, something apparently woke the satellite up from its sleep.

[Scott] did a lot of number crunching to determine that the satellite’s spin rate had only decreased a little from its operational value and that the doppler data matched what he expected. [Scott] can’t read or command the telemetry, so he doesn’t know how healthy the satellite is, but it is at least operational to some degree. It’s really neat to see members of the team that worked on IMAGE leaving comments congratulating [Scott] on the find. They are working to get him data formatting information to see if more sense can be made of the incoming transmissions.

Who knew listening to satellites could be so exciting? If you want to build your own ground station, you might be interested in this antenna mount. If you need to know what’s overhead, this can help.

Hackaday Belgrade Call For Proposals Now Open!

January 22, 2018 by 6 Comments

Prepare yourself for the return of Hackaday Belgrade! Our premier European conference — Hackaday Belgrade — is on 26 May and we want to hear what you’ve been working on. The Call for Proposals is now open. We seek talks and workshops exploring the most interesting uses of technology and the culture that goes along with it. This includes design, prototyping, research, manufacturing, and the stories of people and progress that move hardware hacking forward.

We’ve booked Dom Omladine for the event because it was perfect for our previous Belgrade conference in 2016. The sold-out conference became a living organism of excitement when the Hackaday community from across Europe came together. A spectacular slate of speakers presented topics like designing computing clusters for use in University research programs, combining projection mapping with high powered lasers, building hardware for advertising campaigns, uncovering forgotten projector technology called Eidophor, fully embracing Open Hardware during product development, and so much more. All of this while hundreds in attendance joined forces for some of the best hardware badge hacking we’ve ever seen.

Hackaday Belgrade is the rare kind of opportunity that is worth reorganizing your life to attend. Want to guarantee yourself a ticket? They’re not available yet, but you can hack your way into the conference: submit a proposal! In addition to the adoration of the Hackaday community, accepted speakers will receive free admission. Everyone who submits a quality talk proposal will be given priority when tickets do go on sale. This event will sell out!

For updates, keep an eye on the conference page and pop into the chat on the project page by clicking “Join this project’s team”. Do you know someone who should be a speaker at this conference? Reach out to them personally, share this CFP on social media, or let us know in the comments below so we can make it happen.

Cardboard Wall Is Surprisingly Well Built

January 18, 2018 by 49 Comments

We all built cardboard forts when we were kids. [Paintingcook] has taken it into adulthood with a hand built cardboard wall. He and his wife leased a loft apartment. Lofts are great — one giant space to work with. Plans changed a bit when they found out they had a baby on the way. A single living, working, and sleeping space definitely wouldn’t be good for a newborn, so the couple set about separating a section of the room with a wall.

Sheetrock and steel or wood lumber would be the normal path here. They instead decided to recycle their cardboard moving boxes into a wall. The boxes were formed into box beams, which created the framework of the wall. The two pillars were boxed in and incorporated into the wall itself. The skin of the wall is a random patchwork of cardboard pieces. Most of the construction is completed with 3/8 ” screws and masking tape. Tape won’t last forever, but this is a temporary wall after all.

You might be wondering about fire hazards — sure, cardboard burns more readily than gypsum board, but the apartment is outfitted with sprinklers, which should help on this front. A few commenters on [Paintingcook’s] Reddit thread asked about formaldehyde and other gasses emitting from the cardboard. Turns out he’s an inorganic chemist by trade. He says any outgassing happens shortly after the cardboard is manufactured. It should be safe for the baby.

Cardboard is a great material to work in. You can build anything from robots to computers to guns with it. So get hop the couch, grab that Amazon box, and get hacking!

You’ll Really Want An “Undo” Button When You Accidentally Send A Ballistic Missile Warning

January 16, 2018 by 91 Comments

Hawaiians started their weekend with quite a fright, waking up Saturday morning to a ballistic missile alert that turned out to be a false alarm. In between the public anger, profuse apologies from officials, and geopolitical commentary, it might be hard to find some information for the more technical-minded. For this audience, The Atlantic has compiled a brief history of infrastructure behind emergency alerts.

As a system intended to announce life-critical information when seconds count, all information on the system is prepared ahead of time for immediate delivery. As a large hodgepodge linking together multiple government IT systems, there’s no surprise it is unwieldy to use. These two aspects collided Saturday morning: there was no prepared “Sorry, false alarm” retraction message so one had to be built from scratch using specialized equipment, uploaded across systems, and broadcast 38 minutes after the initial false alarm. In the context of government bureaucracy, that was really fast and must have required hacking through red tape behind the scenes.

However, a single person’s mistake causing such chaos and requiring that much time to correct is unacceptable. This episode has already prompted a lot of questions whose answers will hopefully improve the alert system for everyone’s benefit. At the very least, a retraction is now part of the list of prepared messages. But we’ve also attracted attention of malicious hackers to this system with obvious problems in design, in implementation, and also has access to emergency broadcast channels. The system needs to be fixed before any more chaotic false alarms – either accidental or malicious – erode its credibility.

We’ve covered both the cold-war era CONELRAD and the more recent Emergency Broadcast System. We’ve also seen Dallas’ tornado siren warning system hacked. They weren’t the first, they won’t be the last.

(Image: Test launch of an unarmed Minuteman III ICBM via US Air Force.)

Imagine A Cluster Of ESP32s

January 14, 2018 by 24 Comments

When the ESP32 microcontroller first appeared on the market it’s a fair certainty that somewhere in a long-forgotten corner of the Internet a person said: “Imagine a Beowulf cluster of those things!”.

Someone had to do it, and it seems that the someone in question was [Kodera2t], who has made a mini-cluster of 4 ESP32 modules on a custom PCB. They might not be the boxed computers that would come to mind from a traditional cluster, but an ESP32 module is a little standalone computer with processing power that wouldn’t have looked too bad on your desktop only in the last decade. The WiFi on an ESP32 would impose an unacceptable overhead for communication between processors, and ESP32s are not blessed with wired Ethernet, so instead the board has a parallel bus formed by linking together a group of GPIO lines. There is also a shared SPI SRAM chip with a bus switchable between the four units by one of the ESp32s acting as the controller.

You might ask what the point is of such an exercise, and indeed as it is made clear, there is no point beyond interest and edification. It’s unclear what software will run upon this mini-cluster as it has so far only just reached the point of a first hardware implementation, but since ESP32 clusters aren’t exactly mainstream it will have to be something written especially for the platform.

This cluster may be somewhat unusual, but in the past we’ve brought you more conventional Beowulf clusters such as this one using the ever-popular Raspberry Pi.

LED Stand For Lego Saturn V Boldly Goes Where No Lego Has Gone Before

January 13, 2018 by 10 Comments

Hackers everywhere have spent the last couple of weeks building the remarkable Saturn V Lego models that they got for the holidays, but [Kat & Asa Miller] decided to go an extra step for realism: they built a stand with LED lights to simulate launch. To get the real feel of blast off, they used pillow stuffing, a clear acrylic tube and a string of NeoPixel LEDs. These are driven by an Adafruit Trinket running code that [Asa] wrote to create the look of a majestic Saturn V just lifting off the launchpad with the appropriate fire and fury.  They initially were not sure if the diminutive Trinket would have the oomph to drive the LEDs, but it seems to work fine, judging by the video that you can see after the break.

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