The (RF) Sniff Test

Sometimes the old tricks are the best. [Kevin] learned an old trick about using a ‘scope to sniff RF noise and pays it forward by sharing it in a recent video. He uses an oscilloscope. But does he need some special probe setup? Nope. He quickly makes a little RF pickup probe, and if you have a ‘scope, we’re pretty sure you can make one in a few seconds, too.

Of course, you can get probes made for that, and there are advantages to using them. But the quick trick of quickly and non-destructively modifying the existing probe to pick up RF means you always have a way to make these measurements.

Continue reading “The (RF) Sniff Test”

Three breakout boards connected with a few wires

Breakout Boards For The Blind

Connecting an LED to a battery seems trivial. If you have any knowledge of using breadboards, knowing that red goes with red, and that black goes with black, it’s as easy as tying your shoes. Except there’s one problem: what if you can’t see the difference between red and black? [Tara] had a student who struggled with a problem just like this, so of course, they made a whole suite of breakout boards to the rescue!

Breadboards rely almost completely on the visual cues of rows, columns, and if the part is even in the hole correctly. [Tara] fixed these issues while attempting to keep the usefulness of a breadboard. Using tactile cues rather than the traditional visual, a visually impaired individual can figure out what is positive or negative.

Braille is the obvious choice for general communication of inputs and outputs. Where [Tara]’s ingenuity came in was the method of incorporating Braille into the boards — solder joints. After reading a Hackaday article on solder Braille, [Tara] managed a fitting and efficient method of allowing ease of use.

Currently, the boards are in a prototyping stage; however, if you want to try them out yourself early, let [Tara] know. Others with visual impairments are needed to properly stress test the device. If you are someone who does not struggle with any major visual impairments, it can be hard to put yourself in their shoes. For those empathic (and with VR capabilities) among us, be sure to try it yourself!

Close up of a multi-USB tester PCB

Troubled USB Device? This Tool Can Help

You know how it goes — some gadgets stick around in your toolbox far longer than reason dictates, because maybe one day you’ll need it. How many of us held onto ISA diagnostic cards long past the death of the interface?

But unlike ISA, USB isn’t going away anytime soon. Which is exactly why this USB and more tester by [Iron Fuse] deserves a spot in your toolbox. This post is not meant to directly lure you into buying something, but seen how compact it is, it would be sad to challenge anyone to reinvent this ‘wheel’, instead of just ordering it.

So, to get into the details. This is far from the first USB tester to appear on these pages, but it is one of the most versatile ones we’ve seen so far. On the surface, it looks simple: a hand-soldered 14×17 cm PCB with twelve different connectors, all broken out to labelled test points. Hook up a dodgy cable or device, connect a known-good counterpart, and the board makes it painless to probe continuity, resistance, or those pesky shorts where D+ suddenly thinks it’s a ground line.

You’ll still need your multimeter (automation is promised for a future revision), but the convenience of not juggling probes into microscopic USB-C cavities is hard to overstate. Also, if finding out whether you have a power-only or a data cable is your goal, this might be the tool for you instead.

Close up of a DIY minimalist EDC multitool, a penny, and a paperclip

This Pocket Multitool Weighs Less Than A Penny

A multitool that weighs less than a penny? Yes, it exists. This video by [ToolTechGeek] shows his titanium flat-cut design tipping the scales at only 1.9 grams—lighter than the 2.5-gram copper penny jingling in your pocket. His reasoning: where most everyday carry (EDC) tools are bulky, overpriced, or simply too much, this hack flips the equation: reduce it to the absolute minimum, yet keep it useful.

You might have seen this before. This second attempt is done by laser-cutting titanium instead of stainless steel. Thinner, tougher, and rust-proof, titanium slashes the weight dramatically, while still keeping edges functional without sharpening. Despite the size, this tool manages to pack in a Phillips and flathead screwdriver, a makeshift saw, a paint-lid opener, a wire bender (yes, tested on a paperclip), and even a 1/4″ wrench doubling as a bit driver. High-torque screwdriving by using the long edges is a clever exploit, and yes—it scrapes wood, snaps zip ties, and even forces a bottle cap open, albeit a bit roughly.

It’s not about replacing your Leatherman; it’s about carrying something instead of nothing. Ultra-minimalist, featherlight, pocket-slip friendly—bet you can’t find a reason not to just have it in your pocket.

Continue reading “This Pocket Multitool Weighs Less Than A Penny”

Adjustable Allen Key After All These Years

The Allen key turns 115 this year. It’s strange to believe that in all that time, no one has come up with an adjustable version, but apparently true. Luckily [Chronova Engineering] has taken up the challenge in his latest video.

The video is a fascinating glimpse at the toolmaker’s art–manual machining and careful human judgement. Humans being the fallable creatures we are, the design goes through a few iterations. After the first failure in metal, [Chronova] falls back on 3D printing to rapidly prototype the next six iterations. Given how much work goes into manually machining the designs, we can only imagine the time savings that represents.

The final version is has classic hexagonal rod split in two, so that a chisel-shaped rod can spread the two prongs out to engage the sides of the Allen bolt. Even with that settled, the prongs and wedge had to be redesigned several times to find exact shape and heat-treatment that would work. At this point the range is anything between 4 mm and 6 mm, which is admittedly narrow, but [Chronova Engineering] believes the mechanism has the potential to go wider.

The design is not being patented, but the drawings are available via the [Chronova Engineering] Patreon if you really need an adjustable Allen key and don’t feel like reverse-engineering the mechanism from video. It’s a much larger project than we’ve featured from this channel before– enormous, really, compared to steam engines that fit on pencil erasers or electric motors that squeeze through the eye of a needle.

Our thanks hall-of-fame tipster [Keith Olson] for letting us know about this one. If you want a slice of that fame for yourself, the tips line is always open. Continue reading “Adjustable Allen Key After All These Years”

Calibration, Good Old Calibration

Do you calibrate your digital meters? Most of us don’t have the gear to do a proper calibration, but [Mike Wyatt] shares his simple way to calibrate his DMMs using a precision resistor coupled with a thermistor. The idea is to use a standard dual banana plug along with a 3D-printed housing to hold the simple electronics.

The calibration element is a precision resistor. But the assembly includes a 1% thermistor. In addition to the banana plugs, there are test points to access the resistor and another pair for the thermistor.

Continue reading “Calibration, Good Old Calibration”

Current Source Mixes Old School And New

At first glance, [RobBest]’s constant current source looks old school. The box is somewhat old-fashioned, featuring switches and binding posts. Most importantly, there’s a large analog meter dominating the front panel. Then you notice the OLED display, and you know something’s up.

The device can source or sink a constant current. In addition, it features a timer that calculates milliamp-hours and automatically turns off when not in use. The brain is a PIC 16F1765, which controls the screen, the buttons, and a few relays. While that might seem an odd choice for the processor, it is actually smart. The device has both a DAC and an ADC, plus an internal op amp. The analog output and a single pass transistor control the current flow, while the two relays flip it between a source and a sink.

Without that op amp, the DAC can’t produce much current. However, by passing it through the onboard amplifier, the output can drive about 100 mA, which is sufficient for this project.

This is a classic circuit, but the addition of a CPU and a display gives it capabilities that would have been very difficult to build back in the day. Want to dive into the theory behind constant current sources?  Or just the practical use of a voltage regulator to make one?

Continue reading “Current Source Mixes Old School And New”