Build Yourself A Vacuum Tube VU Meter

March 22, 2024 by Lewin Day 5 Comments

Volume unit (VU) meters are cool — it’s an undeniable fact. For some reason, humans just dig lights that flash along with sounds. You can build a VU meter using LEDs, or bulbs if you’re trapped in 1972. Or, you could use special vacuum tubes. [mircemk] did just that in their latest VU meter project.

The 6E2 vacuum tube is the part for the job in this case. You might think a specialist tube like this is expensive, but they can be had for just a few dollars from online retailers. They were often used as tuning indicators, but here, they’re used as a responsive VU meter instead. However, instead of a single bar going up and down, you get a pair of bars that raise to meet in the middle.

[mircemk] explains all the circuitry required to drive the tubes, and how to hook them up to create a two-channel stereo VU meter. The final circuit largely relies on a transistor, a diode, some passive components, and a DC-DC boost supply to generate 250 V for the tubes.

The final result looks pretty neat, particularly as it’s built into an old-school blue project box. We’ve seen similar projects from [mircemk] before, too. Continue reading “Build Yourself A Vacuum Tube VU Meter” →

Hackaday Podcast Episode 263: Better DMCA, AI Spreadsheet Play, And Home Assistants Your Way

March 22, 2024 by Al Williams 4 Comments

No need to wonder what stories Hackaday Editors Elliot Williams and Al Williams were reading this week. They’ll tell you about them in this week’s podcast. The guys revisit the McDonald’s ice cream machine issue to start. This week, DIY voice assistants and home automation took center stage. But you’ll also hear about AI chat models implemented as a spreadsheet, an old-school RC controller, and more.

How many parts does it take to make a radio? Not a crystal radio, a software-defined one. Less than you might think. Of course, you’ll also need an antenna, and you can make one from lawn chair webbing.

In the can’t miss articles, you’ll hear about the problems with the x86 architecture and how they tried to find Martian radio broadcasts in the 1920s.

Miss any this week? Check out the links below if you want to follow along, and as always, leave your comments!

Direct download in DRM-free MP3.

Continue reading “Hackaday Podcast Episode 263: Better DMCA, AI Spreadsheet Play, And Home Assistants Your Way” →

a DIY smoke grenade pours out smoke from a vape pen assembly

R/C Smoke Grenade Rolls With The Changes

March 22, 2024 by Kristina Panos 9 Comments

[Davis DeWitt] gets to do something that many of us only dream of — build cool working props for movies. This time, the director asked for a realistic smoke grenade that can roll up to a mark and stop on it every take, pouring out smoke the entire time.

[Davis] decided on a hamster ball-esque design that uses a pair of motors that he can control remotely, plus the innards from a vape pen and a tiny fan to distribute the smoke. The motors spin 3D printed wheels using printed gears attached to the shafts, which drive the whole assembly forward or backward.

In order to get everything to fit inside the printed canister, [Davis] had to use the smallest components he could find, like the Seeed Xiao SAMD21 and the DRV8833 motor driver. The whole thing is powered by a pair of 18650s, which, as you might imagine, really factored into the weight distribution scheme. In this case, the batteries act as a pendulum and keep the inner assembly level and not spinning wildly inside the canister.

Finally, it was time for the smoke grenade aesthetics. After what seemed like endless sanding, priming, and masking, [Davis] had a really good-looking smoke grenade that just needed some vinyl lettering and fake wear-and-tear to be complete. Be sure to check it out in action after the break.

We don’t see a lot of grenades around here, but when we do, they’re often keyboards.

Continue reading “R/C Smoke Grenade Rolls With The Changes” →

This Week In Security: Loop DOS, Flipper Responds, And More!

March 22, 2024 by Jonathan Bennett 8 Comments

Here’s a fun thought experiment. UDP packets can be sent with an arbitrary source IP and port, so you can send a packet to one server, and could aim the response at another server. What happens if that response triggers another response? What if you could craft a packet that continues that cycle endlessly? That is essentially the idea behind Loop DoS (Denial of Service).

This unique avalanche of packets has been managed using specific implementations of several different network services, like TFTP, DNS, and NTP. There are several CVEs being used to track the issue, but CVE-2024-2169 is particularly odd, with the description that “Implementations of UDP application protocol are vulnerable to network loops.” This seems to be a blanket CVE for UDP, which is particularly inappropriate given that the first DoS of this sort was first reported in 2009 at the latest.

More details are available in a Google Doc. There some interesting tidbits there, like the existence of cross-protocol loops, and several legacy protocols that are vulnerable by design. The important thing to remember here is you have to have an accessible UDP port for this sort of attack to take place, so if you’re not using it, firewall it.

Flipper Flips Back

We’ve covered the saga of the Flipper Zero vs the Canadian government, in the context of car theft. The short version is that Canada has seen an uptick of car thefts from organized crime. Rather than meaningfully dealing with this problem, the Canadian government went looking for scapegoats, and found the Flipper Zero.

Well now, Flipper has responded, and put simply, the message is “stop the madness”. There has never been a confirmed case of using a flipper to steal a car, and it’s very unlikely it’s ever happened. On a modern car with proper rolling-code security, it’s not meaningfully possible to use the Flipper Zero for the theft. The two primary ways criminals actually steal cars are with dedicated keyfob repeaters and CAN bus hackers.

There is a petition to sign, and for Canadians, Flipper suggests contacting your local member of parliament. Continue reading “This Week In Security: Loop DOS, Flipper Responds, And More!” →

AI Image Generation Meets Virtual Dress Up

March 22, 2024 by Donald Papp 17 Comments

Image generators have really taken off thanks to machine learning, and all kinds of new ideas have been turned on in people’s heads as a result. OOTDiffusion is one such project, its job being to allow virtual try-ons of clothing by combining a picture of a person and an item of clothing, and doing so in a coherent way.

A model sporting a 2021 Remoticon shirt.

When it comes to AI image generators, maintaining consistency of a particular subject in a picture while changing or combining other parts of the image isn’t a trivial task. (If you’re unfamiliar with the basics of how diffusion-type AI image generators work, we have you covered.)

Virtual try-on of clothing is not a new idea, but it’s also far from being a completely solved problem. It’s easy to feed a system high-quality images of people and clothing and ask it to combine them, but the outputs rarely emerge with all their limbs intact, figuratively speaking.

OOTDiffusion addresses the two big challenges in this area: making sure the outputs look natural and realistic, and preserving as much of the garment’s appearance and qualities as possible in the process.

It seems to to a very good job, and you can try it for yourself in the online demo. Check out the research paper for more details, and the GitHub repository provides all the code if you’d like to get a little more hands-on.

Open HT Surgery Gives Cheap Transceiver All-Band Capabilities

March 22, 2024 by Dan Maloney 35 Comments

Watch out, Baofeng; there’s a new kid on the cheap handy talkie market, and judging by this hardware and firmware upgrade to the Quansheng UV-K5, the radio’s hackability is going to keep amateur radio operators busy for quite a while.

Like the ubiquitous Baofeng line of cheap transceivers, the Quansheng UV-K5 is designed to be a dual-band portable for hams to use on the 2-meter VHF and 70-centimeter UHF bands. While certainly a useful capability, these bands are usually quite range-limited, and generally require fixed repeaters to cover a decent geographic area. For long-range comms you want to be on the high-frequency (HF) bands, and you want modulations other than the FM-only offered by most of the cheap HT radios.

Luckily, there’s a fix for both problems, as [Paul (OM0ET)] outlines in the video below. It’s a two-step process that starts with installing a hardware kit to replace the radio’s stock receiver chip with the much more capable Si4732. The kit includes the chip mounted on a small PCB, a new RF choke, and a bunch of nearly invisible capacitors. The mods are straightforward but would certainly benefit from the help of a microscope, and perhaps a little hot air rework. Once the hardware is installed and the new firmware flashed, you have an HT that can receive signals down to the 20-meter band, with AM and SSB modulations, and a completely redesigned display with all kinds of goodies.

It’s important to note that this is a receive-only modification — you won’t be transmitting on the HF bands with this thing. However, it appears that the firmware allows you to switch back and forth between HF receive and VHF/UHF transceive, so the radio’s stock functionality is still there if you need it. But at $30 for the radio and $12 for the kit, who cares? Having a portable HF receiver could be pretty handy in some situations. This looks like yet another fun hack for this radio; we’ve seen a few recently, including a firmware-only band expansion and even a Trojan that adds a waterfall display and a game of Pong. Continue reading “Open HT Surgery Gives Cheap Transceiver All-Band Capabilities” →

Video Poker Takes Your Money In 10 Lines Of BASIC

March 21, 2024 by Donald Papp 14 Comments

It wasn’t easy, but [D. Scott Williamson] succeeded in implementing Jacks or Better Video Poker in 10 lines of BASIC, complete with flashing light and sound! Each round, one places a bet then plays a hand of 5-card draw, hoping to end up with Jacks or better.

This program is [Scott]’s entry into the 2024 BASIC 10 Liner Contest, which at this writing has concluded submissions and expects to announce results on April 6th 2024. Contestants may choose any 8-bit computer system BASIC, and must implement their program within ten lines of code (classically limited to 80 characters per line, but there are different categories with different constraints on line width.)

10 lines of BASIC is truly an exercise in information density.

We’ve seen impressive 10-line BASIC programs before, like this re-implementation of the E.T. video game. (Fun fact: while considered one of the worst video games of all time, there’s a compelling case to be made that while it was a flop, it was ahead of its time and mostly just misunderstood.)

These programs don’t look much like the typical BASIC programs many of us remember. They are exercises in information density, where every character counts. So we’re delighted to see [Scott] also provides a version of his code formatted and commented for better readability, and a logical overview that steps through each line.

He spends a little time talking about the various challenges, as well. For example, hand ranking required a clever solution. IF…THEN conditionals would rapidly consume the limited lines of code, so hands are ranked programmatically. The 52-card deck is also simulated, rather than simply generating random cards on the fly.

The result looks great, and you can watch it in action in the video, just under the page break. If this sort of challenge tweaks your interest, there’s plenty of time to get started on next year’s BASIC 10 Liner Contest. Fire up those emulators!

Continue reading “Video Poker Takes Your Money In 10 Lines Of BASIC” →