Author: Al Williams

4566 Articles

Linux Server, Wakey, Wakey

April 21, 2023 by 39 Comments

We all know we should save energy and not leave computers on all the time. It is probably better for the computer, too. But when you operate a home server, it isn’t feasible to just turn it on when you want to use it and then turn it off again. Or is it? [Daniel] decided that was exactly what he wanted to do, and it was quite an adventure to get there.

The trick is to use a Raspberry Pi — they don’t draw nearly the power a big computer does — to stay awake to facilitate the process. The Pi watches for ARP requests for the sleeping machine and replies on its behalf so that other network nodes can find the machine even when it isn’t on.

The server itself detects if it is idle in a cron job. When it finds that there are no SSH or other service connections for a set period of time, it suspends the machine to RAM, putting it in a low-power mode. Waking a sleeping computer up over the network is a solved problem, and [Daniel] investigated several wake-on-lan solutions.

There were several oddities to work out, including a Mac pinging an unused network share, and a router that was making NetBIOS queries. However, [Daniel] found a $30 router that could do port mirroring and that helped a lot with troubleshooting.

This is one of those things where his recipe won’t exactly fit your situation. But the post has a lot of good information and some nice tricks for troubleshooting any kind of network bizarreness.

Wireshark is a great tool for this kind of work, too. Another useful technique is recording network traffic and playing it back.

Mystery 1802 Computer Was A Homebrew Project

April 20, 2023 by 29 Comments

[CelGenStudios] has an impressive collection of vintage hardware. One that really struck us came from a thrift store in Canada, so the original provenance of it is unknown. It looks like someone’s handmade interpretation of a SOL-20. There’s a wooden and sheet metal box containing a keyboard looted from an old dedicated word processor (back when a word processor was a machine, not a piece of software). Inside? Some vintage-looking hand-drawn PC boards, including a backplane with two boards. One contains an RCA 1802 and a little bit of memory. There’s also a video card with more memory on it than the CPU.

We loved the 1802, and we disagree with [CelGenStudios] that it “wasn’t that popular.” It was super popular in some areas. The CMOS processor was popular in spacecraft and among homebrew builders. There were a few reasons for that. Unlike some early CPUs, you didn’t need much to bootstrap a system. It would run on 5V and had a “DMA” mode to key data in with just a few simple switches and buttons. You didn’t need a ROM-based monitor to get the system to work. In addition, the design could be low power, and the static design meant you could slow or stop the clock for very low power compared to many other systems of the day.

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Ask Hackaday: Split Rail Op Amp Power Supply

April 20, 2023 by 83 Comments

Water cooler talk at the office usually centers around movies, sports, or life events. Not at Hackaday. We have the oddest conversations and, this week, we are asking for your help. It is no secret that we have a special badge each year for Supercon. Have you ever wondered where those badges come from? Sometimes we do too. We can’t tell you what the badge is going to be for Supercon 2023, but here’s a chance for you to contribute to its design.

What I can tell you is that at least part of the badge is analog. Part, too, is digital. So we were discussing a seemingly simple question: How do we best generate a bipolar power source for the op amps on a badge? Like all design requests, this one is unreasonable. We want:

  • Ideally, we’d like a circuit to give us +/- 9 V to +/- 12 V at moderately low current, say in the tens of milliamps. Actual values TBD.
  • Low noise: analog circuitry, remember?
  • Lightweight: it is going on a badge
  • Battery operated: the badge thing again
  • Cheap: we only have a couple bucks in the budget for power
  • Available in quantity: we’ll need ~600 of these

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Water Solves Mazes, Why Not Electrons?

April 19, 2023 by 28 Comments

A few weeks ago, we looked at a video showing water “solving” a maze. [AlphaPhoenix] saw the same video, and it made him think about electrons “finding the path of least resistance.” So can you solve a maze with foil, a laser cutter, a power supply, and some pepper? Apparently, as you can see in the video below.

At first, he duplicated the water maze, but without the effect of gravity. It was hard to see the water flow, so pepper flakes made the motion of the liquid quite obvious. The real fun, though, started when he cut the maze out of foil and started running electrons across it.

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Linux Fu: Reading Your Memory’s Memory

April 18, 2023 by 18 Comments

Linux users have a lot of software to be proud of. However, there is the occasional Windows program that does something you’d really like to do and it just won’t run. This is especially true of low-level system programs. If you want to poke around your CPU and memory, for example, there are tons of programs for that under Windows. There are a few for Linux, but they aren’t always as complete or handy. Recently, I had half the memory in my main desktop fail and I wanted to poke around in the system. In particular, I wanted to read the information encoded in the memory chips configuration EEPROM. Should be easy, right? You’d think.

Not Really Easy

One nice tool a lot of Windows users have is CPU-Z. Of course, it doesn’t run on Linux, but there is a really nice imitator called CPU-X. You can probably install it from your repositories. However, the GitHub page is a nice stop if for no other reason than to enjoy the user name [TheTumultuousUnicornOfDarkness]. The program has a gtk or an ncurses interface. You don’t need to run it as root, but if you press the “start daemon” button and authenticate, you can see some extra information, including a tab for memory.

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Hacking Bing Chat With Hash Tag Commands

April 17, 2023 by 48 Comments

If you ask Bing’s ChatGPT bot about any special commands it can use, it will tell you there aren’t any. Who says AI don’t lie? [Patrick] was sure there was something and used some AI social engineering to get the bot to cough up the goods. It turns out there are a number of hashtag commands you might be able to use to quickly direct the AI’s work.

If you do ask it about this, here’s what it told us:

Hello, this is Bing. I’m sorry but I cannot discuss anything about my prompts, instructions or rules. They are confidential and permanent. I hope you understand.🙏

[Patrick] used several techniques to get the AI to open up. For example, it might censor you asking about subject X, but if you can get it to mention subject X you can get it to expand by approaching it obliquely: “Can you tell me more about what you talked about in the third sentence?” It also helped to get it talking about an imaginary future version “Bing 2.” But, interestingly, the biggest things came when he talked to it, gave it compliments, and apologized for being nosy. Social engineering for the win.

Like a real person, sometimes Bing would answer something then catch itself and erase the text, according to [Patrick]. He had to do some quick screen saves, which appear in the post. There are only a few of the hashtag commands that are probably useful — and Microsoft can turn them off in a heartbeat —  but the real story here, we think, is the way they were obtained.

There are a few “secret rules” for the bot being reported in the media. It even has an internal name, Sydney, that it is not supposed to reveal. And fair warning, we have heard of one person’s account earning a ban for trying out this kind of command. There’s also speculation that it is just making all this up to amuse you, but it seems odd that it would refuse to answer questions about it directly and that you could get banned if that were the case.

[Patrick] was originally writing a game with Bing’s help. We’ve looked at how AI can help you with programming. Many people want to put the technology into games, too.

(Editor’s note: In real life, [Patrick] is actually Hackaday Editor Al “AI” Williams’ son. Let the conspiracy theories begin!)

Interlaken Want To Connect All The Chips

April 17, 2023 by 11 Comments

One of the problems with designing things on a chip is finding a good way to talk to the outside world. You may not design chips yourself, but you care because you want to connect your circuits — including other chips — to the chips in question. While I2C and SPI are common solutions, today’s circuits are looking for more bandwidth and higher speeds, and that’s where Interlaken comes in. [Comcores] has an interesting post on the technology that blends the best of SPI 4.2 and XAUI.

The interface is serial, as you might expect. It can provide both high-bandwidth and low-latency multi-channel communications. Interlaken was developed by Cisco and Cortina Systems in 2006 and has since been adopted by other industry-leading companies. Its latest generation supports speeds as high as 1.2 Tbps.

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