Pumping Concrete

March 29, 2020 by Mike Szczys 39 Comments

Due to social distancing, gym rats throughout the world are turning everyday objects into exercise equipment to keep up the routine without actually hitting the gym. A particularly pleasing version of this are these concrete dumbbells whipped up by the unfortunately named hacker [ShitnamiTidalWave].

If you happen to have half a bag of concrete — quick set or otherwise — out in the shed you can follow the lead on this one. But even if you’re not the kind of person who has “arm day” on your calendar (most of us here in the Hackaday bunker do not) this hack is still worth your time. Mold making is one of the uber-useful skills you should have in your hacker toolkit and [ShitnamiTidalWave] has done both an excellent job of building a mold, and of explaining the process.

Raw material for this one couldn’t be easier; each mold is made out of plywood, 2×4 stud, and nails, along with handles made of 3/4″ PVC pipe. The studs were ripped down and used to create the 45 degree chamfers at each edge. Mold-making veterans will tell you that release agent is a must and in this case rubbing the insides of the molds with wax made it a snap to pry the wooden forms off of the set concrete.

Concrete has a tendency to crack as it cures so if you’re casting large pieces like this touch-sensitive concrete countertop you might want to throw in some fiber reinforcement to the mix. If you’re keen on seeing some of the more impressive mold-making skills at work, check out how metal parts are cast from 3D-printed molds and how a master duplicates parts using silicone molds.

[via r/DIY]

How To Try Generative Optimization At Home

March 29, 2020 by Donald Papp 29 Comments

Chairs, spokes on a wheel, bridges, and all kinds of other load-bearing objects are designed such that material is only present where it is needed. There’s a process by which the decisions about how much material to put and where is determined by computer, and illustrating this is [Adam Bender]’s short primer on how to use generative optimization in Autodesk’s Fusion 360 (which offers a variety of free licenses) using a wheel as an example.

Things start with a solid object and a definition of the structural loads expected. The computer then simulates the force (or forces) involved, and that simulation can be used to define a part that only has material where it’s really needed. The results can be oddly organic looking, and this process has been used to optimize spacebound equipment where every gram counts.

It’s far from an automated process, but it doesn’t look too difficult to navigate the tools for straightforward designs. [Adam] cautions that one should always be mindful of the method of manufacturing when designing the part’s final form, which is always good advice but especially true when making oddball shapes and curves. To see the short process in action, watch the video embedded below.

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Got Me Feeling Blue

March 29, 2020 by Brian McEvoy 22 Comments

Sleep schedules are an early casualty in the fight to be productive. Getting good sleep is an uphill battle, so anything that can help us is a welcome ally. We all know about the phone and computer settings that turn down the infamous blue hues at sunset, but what about when you want more blue light? Maybe you want to convince your body to stay awake to pre-acclimate for a trip across time zones. Perhaps you work or live in a place that doesn’t have windows. Menopause introduces sleep trouble, and that is a perilously steep hill.

[glowascii] takes the approach of keeping-it-simple when they arrange six blue LEDs under a flesh-tone patch, which isn’t fooling anyone and powers the lights with a USB power pack. Fremen jokes aside, light therapy is pricey compared to parts some of you have sitting in a drawer. Heck, we’d wager that a few of you started calculating the necessary resistor sizes before you read this sentence. Even if you don’t need something like this, maybe you can dedicate an afternoon to someone who does.

DIY therapy has a special place in our (currently organic) hearts, such as in this rehabilition glove or a robot arm.
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Ondophone On Point

March 28, 2020 by Brian McEvoy 5 Comments

The name Ondophone is a mash-up of two instruments, the Marxophone, and the ondes martenot. From the Marxophone, [Wintergatan] borrows the spring-loaded hammers, which repeatedly strike a string once activated. The ondes martenot loans its Theremin-like sound and ability to lean back on western semi-tone notes. Mating such different instruments requires a team, and much like the name, it produces a splendid blend.

At the left-hand side of the Ondophone, we see the spring-hammer battering away on a steel string whenever the neck moves up or down. Next to it is an Ebow that vibrates a string with an electromagnet and can maintain a note so long as it has power. Hidden within the neck are magnets to demarcate semi-tone locations, so it’s possible to breeze past them for a slide sound or rest on them to follow a tune.

The combination of intermittent hammering and droning lends well to the “creepy” phase of the song, which leads segues to the scope-creep that almost kept this prototype on the drawing board. The video talks about all the things that could have been done with this design, which is a pain/freedom we know well. KISS that Ondophone headline act goodbye.

The ondes martenot is an early electronic instrument, so we’ve some high-tech iterations, and if you haven’t heard what’s possible with a DIY Ebow, we will harp on you.

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A Really Garbage Project

March 28, 2020 by Al Williams 6 Comments

No matter who you are, you produce garbage of some kind or another. Two students decided they wanted to create a smart garbage can that could alert them when the can is full or even when it is stinky.

We will go on on the record: we didn’t know that an alcohol sensor could tell if your garbage is stinky, so if that works, that’s a new one on us. However, it makes a certain kind of sense because garbage ferments. We thought garbage smelled because of hydrogen sulfide and methane.

Trash cans have a tough life, so if you really want to duplicate this, you’ll probably want to mount things a bit more securely. The software, however, runs everything through a cloud service and from there can use Blynk for a phone app and IFTTT to ship things to a spreadsheet, should you care to track your garbage history statistics.

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An Open Source Shipboard Computer System

March 28, 2020 by Tom Nardi 21 Comments

We’re not sure how many of you out there own a boat large enough to get its own integrated computer network, but it doesn’t really matter. Even if you can’t use this project personally, it’s impossible not to be impressed with the work [mgrouch] has put into the “Bareboat Necessities” project. From the construction of the hardware to the phenomenal documentation, there’s plenty that even landlubbers can learn from this project.

In its fully realized form, the onboard computer system includes several components that work together to provide a wealth of valuable information to the operator.

What [mgrouch] calls the “Boat Computer” contains a Raspberry Pi 4, a dAISy AIS receiver, an RTL-SDR, a GPS receiver, serial adapters, and the myriad of wires required to get them all talking to each other inside a weatherproof enclosure. As you might expect, this involves running all the connections through watertight panel mounts.

Combined with a suite of open source software tools, the “Boat Computer” is capable of interfacing with NMEA sensors and hardware, receive weather information directly from NOAA satellites, track ships, and of course plot your current position on a digital chart. The computer itself is designed to stay safely below deck, while the operator interacts with it through an Argonaut M7 waterproofed HDMI touch screen located in the cockpit.

For some people, that might be enough. But for those who want to do big, [mgrouch] further details the “Boat Gateway” device. This unit contains an LTE-equipped WiFi router running OpenWrt and all the external antennas required to turn the boat into a floating hotspot. Of course it also has RJ45 jacks to connect up to the other components of the onboard system, and it even includes an M5Stack Core with LAN module so it can display a select subset of sensor readings and navigational data.

If you’d like to do something similar on a slightly smaller scale, we’ve seen sailing computers that pushed all the data to a wearable display or even a repurposed eReader.

Poor Maintenance Could Have Led To Fatal B-17 Crash

March 28, 2020 by Tom Nardi 49 Comments

In October the Nine-O-Nine, a fully restored Boeing B-17G bomber owned and operated by the Collings Foundation, crashed with thirteen people on board. After landing hard and skidding into the de-icing tanks at the Bradley International Airport, all but the tail and port wing of the 74 year old WWII aircraft was destroyed. Seven lives were lost in the accident, including that of Pilot Ernest “Mac” McCauley, who was regarded as one of the most experienced B-17 pilots in the world.

While the National Transportation Safety Board (NTSB) investigation is still ongoing and hasn’t made a final determination as to what ultimately brought down the Nine-O-Nine, enough serious maintenance issues were uncovered while examining the wreckage that the Federal Aviation Administration (FAA) has decided to rescind the Collings Foundation’s license to conduct any more paid flights on their remaining WWII aircraft. While many have spoken out in support of these “living history” flights, the FAA says they must be conducted in such a way that they don’t hinder the safety of other air traffic.

With the vast majority of the B-17’s airframe gone, the NTSB investigation has focused on the four 1,200 horsepower Wright R-1820 “Cyclone” engines recovered from the crash site. Investigators found that hastily attempted repairs to engine number 4, which is believed to have failed in-flight, were actually hindering normal operation:

Regarding engine 4, to prevent the magneto “P” leads from separating from the
magnetos, someone had attempted to rig the magneto leads in place with safety wire.

Inspection and testing of engine 4 left magneto revealed the movement of the safety-wired lead caused grounding to the case, which rendered the magneto lead inoperative.

Further, all of the spark plugs in the number 3 and 4 engines were found to be fouled and had electrode gaps that were out of tolerance. From an examination of the aircraft’s maintenance records, it was also learned that an arcing and burned wire had been replaced without any investigative steps taken to find what caused the failure to begin with.

With basic maintenance tasks either not being performed or at least done incorrectly, the FAA has called into question the culture of safety at the Collings Foundation. The paper is careful not to directly accuse the Foundation or any of its staff with outright negligence, but the implication seems clear.

The loss of Nine-O-Nine hit especially close to home for Hackaday. Just a month prior to the crash we had the opportunity to tour the aircraft, and came away with a newfound respect for not only those who designed and built the iconic bomber but the brave young men who flew it. Losing such a rare and historically significant aircraft and its crew was already a tragedy, but to find that negligence may be to blame is truly inexcusable.