Electric Airboat For Getting You Across Thin Ice

February 25, 2021 by 19 Comments

Even with all the technological progress civilization has made, weather and seasons still have a major impact on our lives. [John de Hosson] owns a cabin on an island in a Swedish lake, and reaching it involves crossing 500 m of water. In summer this is done with a conventional boat, and in winter they can simply walk across the thick ice, but neither of these is an option on thin ice in the spring or fall. To solve this [John] built an electric airboat, and it looks like a ton of fun in the video after the break

The construction is simple but functional. A 3.3 m flat-bottomed aluminum boat has used a base, and an aluminum frame was bolted on for the motor and propeller. The motor is an 18 kW brushless motor, with a 160 cm/63-inch carbon fiber propeller. Power comes via a 1000 A ESC from a 100V 3.7 kWh Lipo pack mounted in a plastic box. Steering is very similar to a normal airboat, with a pair of air rudders behind the propeller, controlled by a steering lever next to the driver’s seat. The throttle is an RC controller with the receiver wired to the ESC.

Performance is excellent, and it accelerates well on ice and slush, even with two people on board. [John] still plans to make several improvements, with a full safety cage around the propeller being at the top of the list. He is also concerned that it will capsize on the water with the narrow hull, so a wider hull is planned. [John] has already bought a large steering servo to allow full remote control for moving cargo, with the addition of an FPV system. We would also add an emergency kill switch and waterproofing for the electronics to the list of upgrades. It looks as though the battery box is already removable, which is perfect for getting it out of the cold when not in use.

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Paul Taylor Opened The Lines Of Telecommunication For The Hearing-Impaired

February 23, 2021 by 23 Comments

These days, nearly everyone communicates through some kind of keyboard, whether they are texting, emailing, or posting on various internet discussion forums. Talking over the phone is almost outmoded at this point. But only a few decades ago, the telephone was king of real-time communication. It was and still is a great invention, but unfortunately the technology left the hearing and speaking-impaired communities on an island of silence.

Paul and an early TDD. Image via Rochester Institute of Technology

Engineer and professor Paul Taylor was born deaf in 1939, long before cochlear implants or the existence of laws that called for testing and early identification of hearing impairment in infants. At the age of three, his mother sent him by train to St. Louis to live at a boarding school called the Central Institute for the Deaf (CID).

Here, he was outfitted with a primitive hearing aid and learned to read lips, speak, and use American sign language. At the time, this was the standard plan for deaf and hearing-impaired children — to attend such a school for a decade or so and graduate with the social and academic tools they needed to succeed in public high schools and universities.

After college, Paul became an engineer and in his free time, a champion for the deaf community. He was a pioneer of Telecommunications Devices for the Deaf, better known as TDD or TTY equipment in the US. Later in life, he helped write legislation that became part of the 1990 Americans with Disabilities Act.

Paul was diagnosed with Alzheimer’s in 2017 and died in January of 2021 at the age of 81. He always believed that the more access a deaf person had to technology, the better their life would be, and spent much of his life trying to use technology to improve the deaf experience.

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Pelton Turbine Development For An Air Powered Model Helicopter

February 23, 2021 by 18 Comments

[Tom Stanton] has been messing around with compressed air power for a few years now, and most of his work focused on piston engines. He likes using 2-liter soda bottles as lightweight tanks but their capacity is limited, so the nozzle can be a maximum of 1 mm in diameter if he wants to produce thrust for 30 seconds or longer using a turbine. Pelton turbines have been in use for a long time, especially for hydroelectric systems, and they use small diameter nozzles, so he decided to experiment with a pneumatic Pelton turbine. (Video, embedded below.)

Pelton wheels are water wheels with specially designed buckets to efficiently extract energy from a high-velocity jet of water. [Tom] 3D printed several geared Pelton turbines and started doing bench tests with a propeller and a load cell to gather empirical data. With the help of high-speed video of the tests, he quickly realized that the turbine efficiency is highly dependent on the load. If the load is too small or too large, the moving air will not come to a complete standstill, and energy will be wasted. [Tom] also suspected that some moving air was escaping from the bucket, so he created a version that enclosed the buckets with a ring on the outer perimeter, which increased the peak thrust output by 65%. Compared to his diaphragm air engine design, the peak thrust is higher, but the overall efficiency is less. [Tom] believes there is still room for improvement, so he plans to continue working on the Pelton turbine concept, with the hopes of building an air-powered model helicopter that can lift off. Continue reading “Pelton Turbine Development For An Air Powered Model Helicopter” →

Ghidra Used To Patch Fahrenheit Into An Air Quality Meter

February 15, 2021 by 73 Comments

Even though most of the world population couldn’t tell you what room or body temperature is in Fahrenheit, there are some places on this globe where this unit is still in common use. For people in those areas, it’s therefore a real hassle when, say, a cheap Chinese air quality measurement systems only reports in degrees Celsius. Fortunately, [BSilverEagle] managed to patch such a unit to make it display temperature in Fahrenheit.

The reverse engineering begins by finding a way to dump the firmware. It’s nice to hear that [BSilverEagle] used some the skills demonstrated in [Eric Shlaepfer’s] PCB reverse engineering workshop from Hackaday Remoticon last November to trace out the debug header and the SWD pins of STM32F103C8 MCU. After that, OpenOCD could be used to dump the firmware image, with no read protection encountered. The firmware was then reverse-engineered using Ghidra, so that [BSilverEagle] could figure out where the temperature was being calculated and where the glyph for the Celsius symbol was stored. From there this it was a straight-forward rewrite of those two parts of the original firmware to calculate the temperature value in Fahrenheit, change the glyph and reflash the MCU.

So why buy this thing in the first place if it didn’t spit out units useful for your current locale? Cost. Buying this consumer(ish) device was about the same cost as buying the individual parts, designing and manufacturing the PCB, and writing the firmware for it. The only downside for their use case was the lack of Fahrenheit. Not a problem for those who demand full control of the hardware they own.

Need a boot camp for using Ghidra? Matthew Alt put together a spectacular video series on Reverse Engineering with Ghidra.

PC Overclocking With An Air Conditioner

February 11, 2021 by 51 Comments

We never insist that a hack be practical. [Tech Ingredients] is living proof as they modded a computer case to use a window air conditioner for overclocking a computer. They think they haven’t hit the ceiling yet, and got their AMD Ryzen 8-core processor up to 4.58 GHz.

An advantage of forcing air from an air conditioner is that the air forced into the system is quite dry and clean. The trick is to create a simple duct to attach to a 5,000 BTU air conditioner. It doesn’t actually interface with the CPU cooling block, instead it just forces cool air into the case and this tends to cool everything inside. Admittedly, it isn’t any worse than plunging your computer in liquid nitrogen, and we’ll admit that air conditioning units are made to keep large areas cold and work at high duty cycles. With the air conditioning running, they disconnected at least some of the stock fans. The temperatures stayed cool even at high speeds.

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A Hair-Raising Twist On Infinity Mirrors

February 10, 2021 by 6 Comments

Just when we thought we’d seen it all in the infinity mirror department, [FieldCrafting] blazed a tiny, shiny new trail with their electroplated infinity mirror hair pin. We’d sure like to stick this in our French twist. Fortunately, [FieldCrafting] provided step-by-step instructions for everything from the 3D printing to the copper electroplating to the mirror film and circuitry application.

And what tiny circuitry it is! This pin is powered by a coin cell and even has a micro slider switch to conserve it. The stick parts are a pair of knitting needles, which is a great idea — they’re pointy enough to get through hair, but not so pointy that they hurt.

[FieldCrafting] was planning to solder 1206 LEDs to copper tape and line the cavity with it, but somehow the CAD file ended up with 0603, so there wasn’t enough space for two tape traces. We think it’s probably for the better — [FieldCrafting]’s solution was to use two-conductor wire, strategically stripped, which seems a lot less fiddly than trying to keep two bare tape traces separated and passing pixies.

Don’t have enough hair for one of these? Surely you could use some handsome infinity coasters to round out that home bar setup.

This Hot Air Gun Is Either A Work Of Genius Or Lethal, We Can’t Decide

January 31, 2021 by 31 Comments

One of the essentials on the bench is some form of hot air gun. Whether it’s a precision tool intended for reworking PCBs or the broad-stroke item used for paint stripping, we’ve all got one somewhere. The paint-stripping variety are pretty cheap, but not as cheap as [Porcas Pregos e Parafusos]’s home made hot air gun. This slightly hair-raising device is made from a variety of junk parts and delivers hot air, though we suspect the possibility for burning the operator remains high.

At its heart is one of those mains powered water boiler elements designed to be lowered into a cup or similar, and since such devices would burn out if not cooled in some way, there is a fan from a microwave oven passing air over it. The whole thing sits inside an aluminium cone cut from a circular cake tin, and is held together on a wooden chassis to which the handle and power switch from a defunct electric drill provide the operator with something to hold on to.

As you can see from the video below the break it makes for an effective hot air gun, but one that we’re guessing you’d soon learn to avoid touching on the metal cone. Still, as a community we’re used to this with our soldering irons, as the RevSpace T-shirt puts it: “If it smells like chicken, you’re holding it wrong“.

Strangely, this isn’t the first DIY heat gun we’ve seen.

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