Author: Al Williams

4338 Articles

Robot Goes To Summer Camp

November 26, 2023 by 3 Comments

There are a lot of hobby and educational robots that have a similar form factor: a low, wide body with either wheels or tracks for locomotion. When [Alexander Kirilov] wanted to teach a summer robot camp, he looked at several different commercial offerings and found all of them somewhat lacking. His wish list was a neat-looking compact robot that was easy to extend, had various sensors, and would work with Python. Finding nothing to his liking, he set out to make his own, and Yozh robot was born.

The robot certainly looks neat. There is a color TFT display, seven reflective sensors pointing down, two laser time-of-flight sensors facing forward, an IMU, and some LEDs. There are plenty of expansion ports, too. You can check out the code that runs it, too.

Continue reading “Robot Goes To Summer Camp” →

In New Doctor’s Office, Stethoscope Wears You

November 26, 2023 by 28 Comments

The medical professional wearing a stethoscope is a familiar image, but Northwestern University wants to change that. Instead of someone hanging an ancient device around their neck to listen inside of you, they want to put sticky sensors on patients to continuously monitor sounds from hearts, lungs, and the GI tract.

The tiny devices stick to your skin and wirelessly beam audio to clinicians for analysis. They’ve tested the devices on people ranging from people with chronic lung disease to premature babies. In fact, you can hear breath sounds (and crying) from a microphone attached to a baby in the video below. The device uses noise suppression to remove the crying sounds effectively.

Continue reading “In New Doctor’s Office, Stethoscope Wears You” →

Heat Pump Dryer Explained

November 25, 2023 by 98 Comments

Historically, having a washer and a dryer in your house requires “a hookup.” You need hot and cold water for the washer as well as a drain for wastewater. For the dryer, you need either gas or — in the US — a special 220 V outlet because the heating elements require a lot of wattage, and doubling the voltage keeps the current levels manageable. You also need a bulky hose to vent hot moist air out of the house. But a relatively new technology is changing that. Instead of using a heater, these new dryers use a heat pump, and [Matt Ferrell] shows us his dryer and discusses the pros and cons in a video you can below. We liked it because it did get into a bit of detail about the principle of operation.

These dryers are attractive because they use less power and don’t require gas or a 220 V outlet. They also don’t need a vent hose which means they can sit much closer to the wall and take up less space. Heat pumps don’t convert electrical energy into heat like a normal heating element. Instead, it uses a compressor to move heat from one place to another. In this case, the dryer heats the air using the heat pump. That causes water in the clothes to evaporate into the air. The heat pump dryer then uses a second loop to cool the air, condensing the water out so the it can reheat the air and start the whole cycle over again.

Continue reading “Heat Pump Dryer Explained” →

Mystery Signal! Are You Ready For Your Mystery Signal?

November 24, 2023 by 2 Comments

Like many people [Dan Greenall] spent a lot of time in the 1970s listening to shortwave radio. While you often think of that as a hobby involving listening to broadcast stations, some people like to listen to other communications such as airliners, ships, military, and even spy stations. These days, if you hear a strange signal you are probably only one internet search away from identifying what it is. But back then, you had to depend on word-of-mouth or magazines to figure things like that out. [Dan] found a recording of a mysterious military-like signal he made in 1971 on 14.85 MHz. He decided that maybe now, all these years later, he could finally identify it.

The operator in the recording is counting and mentions “Midway Island,” famous for a World War II battle and part of the Leeward Islands in the Pacific. Thanks to the internet and the law of six degrees of separation, [Dan] found [Chuck Kinzer] who was a Midway Navy vet.

Continue reading “Mystery Signal! Are You Ready For Your Mystery Signal?” →

DIY Smart Washing Machine Redesign

November 24, 2023 by 18 Comments

[Mellow Labs] wanted a smart washer and built a simple controller. However, he found out after a few weeks it wasn’t working how he wanted. The detergent quit flowing, and he washed clothes with no soap for a week! So, a redesign was in order. You can follow the process and the result in the video below.

A bit of 3D printing, a larger pump, and proper voltage made a big difference. We didn’t see the print files, but unless you have the exact same setup, you’d probably have to customize it anyway. There is a real-time hand-drawn schematic, and the software is probably not hard to pull off the video screen (it is only 18 lines).

Continue reading “DIY Smart Washing Machine Redesign” →

Life Imitates ART (ART-13, That Is)

November 23, 2023 by 4 Comments

[Mr. Carlson] has been restoring vintage military radios, and as part of his quest, he received an ART-13 transmitter. Before he opened the shipping box, he turned on the camera, and we get to watch from the very start in the video below. These transmitters were originally made by Collins for the Navy with an Army Air Corps variant made by Stewart-Warner. Even the Russians made a copy, presumably by studying salvaged units from crashed B-29s.

The transmitter puts out 100 watts at frequencies up to 18.1 MHz. The tubes needed a plate supply, and so, like many radios of the era, this one used a dynamotor. Think of it as a motor running at one voltage and turning a generator that produces a (usually) higher voltage. If you ever used a radio with one, you know you didn’t need an “on the air” sign — the whine of the thing spinning would let everyone know you had the key or microphone button pushed down. It’s an interesting piece of bygone tech that we’ve looked into previously.

The transmitter wasn’t in perfect shape, but we’ve seen worse. When the lid comes off, you can practically smell the old radio odor. There are tubes, coils, and even a vacuum relay, presumably for transmit/receive switching of the antenna. [Carlson] also tears open the dynamotor which is something you don’t see every day.

Continue reading “Life Imitates ART (ART-13, That Is)” →

Linux Fu: Easy Kernel Debugging

November 22, 2023 by 2 Comments

It used to be that building the Linux kernel was not easy. Testing and debugging were even worse. Nowadays, it is reasonably easy to build a custom kernel and test or debug it using virtualization. But if you still find it daunting, try [deepseagirl’s] script to download, configure, build, and debug the kernel.

The Python program takes command line arguments so you can select a kernel version and different operations. The script can download the source, patch the configuration, build the kernel, and then package it into a Debian package you can boot under qemu. From there, you can test and even debug with gdb. No risk of hosing your everyday system and no need to understand how to configure everything to run.

Continue reading “Linux Fu: Easy Kernel Debugging” →