Author: Zoe Skyforest

3703 Articles

Toothbrush Speed Controller Secrets Revealed

May 18, 2023 by 21 Comments

Typically, when we want to build something with a DC motor, we might grab a bunch of AAs, or a single lithium cell at the very least. Electric toothbrushes often run on more humble power sources, like a single NiMH battery. They’re designed to get useful motion out of just 1.2V, and [Marian Hryntsiv] has taken a look at what makes them tick.

The article focuses on an electric toothbrush built around the Low Voltage GreenPAK™ SLG47513 chip. It’s designed to work at voltages from just 1 to 1.65 V. To make the most of the limited power available, the toothbrush stays in sleep mode most of the time when it’s not working in oral health.

[Marian] steps through the various parts of the circuit, and also explains the unique functionality baked into the brush. Of particular interest are the timer routines that guide the user through brushing each section of the mouth in turn, before a notification that tells them that 2 minutes of brushing time has elapsed. There’s also a useful explanation of the inductive charging method used.

Electric toothbrushes may be mundane home items today, but they’re an example of a product that has largely already been optimized to the nth degree. Until laser-based plaque removal or enamel regeneration technology gets off the ground, this is as good as it gets. We can dream, though!

 

Big Tactile Button Is Silly But Cool

May 18, 2023 by 8 Comments

Every hacker is familiar with those teeny little tactile buttons that are so enjoyable to click over and over again. [ROBO HUB] has built a giant version as a tribute, and it works just like the real thing!

The giant button has been scaled up 20 times compared to the original. For simplicity’s sake, [ROBO HUB] designed this replica to use materials readily available around the home. Thanks to its cardboard construction, it’s easy to replicate with a minimum of tools. One need merely cut out the various sections before assembling them together with hot glue, with popsicle sticks serving as the legs. A juice bottle is used as the primary button itself, with aluminium foil serving as the contacts and rubber bands standing in for the spring.

It’s not the most useful button, given that it it’s quite fragile and has a weak spring return. However, it would be a great teaching tool to show students exactly what’s going on inside an actual button. As a bonus, it looks like it would be remarkably fun to pound on to activate some kind of massive air horn. Just an idea.

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Revisiting Folk Wisdom For Modern Chronic Wound Care

May 18, 2023 by 81 Comments

In the constant pursuit of innovation, it’s easy to overlook the wisdom of the past. The scientific method and modern research techniques have brought us much innovation, which can often lead us to dismiss traditional cultural beliefs.

However, sometimes, there are still valuable kernels of truth in the folklore of yesteryear. This holds true in a medical study from Finland, which focused on the traditional use of spruce resin to treat chronic wounds, breathing new life into an age-old therapy.

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Drone Flies For Five Hours With Hydrogen Fuel Cell

May 18, 2023 by 82 Comments

Multirotor drones have become a regular part of daily life, serving as everything from camera platforms to inspection tools and weapons of war. The vast majority run on lithium rechargeable batteries, with corresponding limits on flight time. A company called Hylium hopes to change all that with a hydrogen-powered drone that can fly for up to five hours.

The drone uses a hydrogen fuel cell to provide electricity to run the drone’s motors and other electronic systems. Thanks to the energy density advantage of hydrogen versus lithium batteries, the flight time can be greatly extended compared to conventional battery-only drones. Details are scant, but the company has gone to some lengths to build out the product beyond a simple tech demonstrator, too. Hylium touts useful features like the short five-minute refueling time. The drone also reportedly features a night vision camera and the capability to transmit video over distances up to 10 kilometers, though some of the video of these features appears to be stock footage.

Hylium claims the liquid hydrogen canister used for the drone is drop-safe in the event of a problem. Notably, the video suggests the company tested this by dropping the canister concerningly close to an active motorway, but from what we see, nothing went awry.

A drone that can fly for five hours would be particularly useful for autonomous surveillance and inspection roles. The additional loiter time would be advantageous in these roles. We’ve seen other aero experimenters exploring the use of hydrogen fuel cells, too.

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Machining A Golf Ball To Make A Lovely Tactile Volume Knob

May 17, 2023 by 11 Comments

Golf balls are wonderfully tactile things. They have a semi-grippy covering, and they’re a beautiful size and weight that sits nicely in the hand. Sadly, most of them just get smacked away with big metal clubs. [Jeremy Cook] recognized their value as a human interface device, though, and set about turning one into a useful volume knob.

The trick here is in the machining. [Jeremy] used a 3D printed jig to hold a golf ball tightly in place so that it could be machined using a milling machine. With the bottom taken off and a carefully-designed 3D printed insert in the bottom, the golf ball is ready to be used as a knob for a volume control. As for the hardware side of things, [Jeremy] used an existing USB keypad, fitting the golf ball onto the encoder for volume and seek control in various programs.

The results sadly weren’t ideal. While the golf ball sits nicely upon the encoder, [Jeremy] found the device uncomfortable to use. Size may be an issue, but we also suspect the crowding of the surrounding buttons has a role to play. It forces the wrist into an uncomfortable curve to access the ball without hitting the surrounding controls. Without that, it may be greatly improved.

Files are available for those wishing to make their own. We don’t get a lot of golf ball builds here on Hackaday, but we’d love to see more. Hit up the tipsline if you’ve got ’em. Video after the break.

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Cheaper Sodastream With A Big CO2 Tank Is A Semi-Dangerous Way To Save

May 17, 2023 by 72 Comments

Sodastream machines are a fun way to turn tap water into carbonated water. However, the canisters are expensive and generally require a trip to the store to get a replacement. Lifehacker has a workaround that may make life easier for the bubble-addicted set.

The trick is simple: simply buy a larger bottle of CO2, and hook it up to the Sodastream in place of the regular cartridge. CO2 can be bought in large cylinders at a far cheaper rate than Sodastream will charge you for their proprietary canisters. All you need is a local supplier of food-grade CO2 in cylinders, and you can visit them when you need a refill or swap.

There are several caveats, though, which the comment section dicussed when we featured a similar hack before. Getting an extra-large CO2 canister can pose a risk to life if there’s a leak. Alarms may not save you as the heavy gas has a tendency to lurk low to the ground. You should also consider using a regulator to lower the pressure from your large canister to something closer to the levels the Sodastream machine is built to withstand. Beyond that, you want to ensure you’re using food-grade CO2. Don’t go bubbling cheap welding gas through your water if you want to live a long and healthy life.

It’s a neat hack, it’s just one that requires you to practice proper gas safety at all times. Reports are that a cylinder costing less than $200 can last you for several years though, with ultra-cheap refills, so it may indeed be worth the hassle! Go forth and bubble, friends.

Microbubbles And Ultrasound: Getting Drugs Through The Blood-Brain Barrier

May 16, 2023 by 19 Comments

The brain is a rather important organ, and as such, nature has gone to great lengths to protect it. The skull provides physical protection against knocks and bumps, but there’s a lesser-known defense mechanism at work too: the blood-brain barrier. It’s responsible for keeping all the nasty stuff – like bacteria, viruses, and weird chemicals – from messing up your head.

The blood-brain barrier effectively acts as a filter between the body’s circulatory system and the brain. However, it also frustrates efforts to deliver drugs directly to the brain for treating conditions like brain tumors. Now, scientists have developed a new technique that may allow critical life saving drugs to get through the barrier with the help of ultrasound technology. 

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