Misc Hacks

4055 Articles

Behind The X86 Pipeline Curtain

June 19, 2023 by 12 Comments

We’ve often heard that modern x86 CPUs don’t really execute x86 instructions. Instead, they decode them into RISC instructions that are easier to schedule, pipeline, and execute. But we never really looked into that statement to see if it is true. [Fanael] did, though, and the results are very interesting.

The post starts with a very simple loop containing four instructions. In a typical RISC CPU — RISC-V — the same loop requires six instructions. However, a modern CPU is likely to do much more than just blindly convert one instruction set to another.

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BIOS POST Card Built Using Raspberry Pi Pico

June 13, 2023 by 18 Comments

A computer’s BIOS includes basic diagnostic tools for troubleshooting issues. Often, we rely on the familiar beeps from the POST system for this reason. However, error codes are also available via hardware “POST Cards” that were particularly popular in the 1990s. [Mr. Green] has now built a POST card using readily-available modern hardware.

[Mr. Green] built the device to help troubleshoot an x86 based firewall appliance that was having trouble. Like many x86 systems, it featured a Low Pin Count (LPC) bus which can be used to capture POST troubleshooting codes. By hooking up a Raspberry Pi Pico to the LPC bus on the firewall’s motherboard, it was possible to get it to display the POST error codes on some LEDs. This is of great use in the absence of a conventional PC speaker to sound the error out with beeps.

The build can be used for POST-based troubleshooting on any x86 system with an LPC bus. Files are on Github for those eager to replicate the build. We’ve seen similar work before, too. Video after the break.

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Arduino-Powered Missile System Uses Ultrasound To Aim

June 13, 2023 by 14 Comments

In the real world, missile systems use advanced radars, infrared sensors, and other hardware to track and prosecute their targets. [Raspduino Uno] on YouTube has instead used ultrasound for targeting for an altogether simpler desktop fire control solution.

This fun build uses a common off-the-shelf USB “missile launcher” that fires foam darts. To supply targeting data for the launcher, an Arduino Uno uses an ultrasonic sensor pair mounted atop a servo. As the servo rotates, the returns from the ultrasonic sensor are plotted on a screen run by a Raspberry Pi. If an object is detected in the 180-degree field of view of the sweeping sensor, a missile is fired using the dart launcher.

It’s a relatively simple build, but nonetheless would serve as a useful classroom demonstration of radar-like targeting techniques to a young audience. Real military hardware remains altogether more sophisticated. Video after the break.

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Cheap USB Sniffer Has Wireshark Interface

June 13, 2023 by 39 Comments

If you’ve done any development on USB hardware, you’ve probably wished you could peek at the bits and bytes as they pass through the data lines. Sometimes, it’s the only way to properly understand what’s going on. [ataradov]’s USB sniffer is built to do just that. 

To sniff high-speed USB communications, the device relies on a Lattice LCMXO2 FPGA and a Cypress CY7C68013A microcontroller, paired with a Microchip USB3343 USB PHY. This setup is capable of operating at data rates of up to 40-50 MB/s, more than enough to debug the vast majority of USB peripherals on the market.

The device is built specifically for use with Wireshark. Most commonly used for network packet sniffing, Wireshark can also be used with a wide variety of other capture hardware for other debugging tasks, as seen here. In addition to live sniffing, it also allows captured data to be saved for later analysis.

If you need this tool, spinning up your own is straightforward. Gerber files are available and the required components can be bought off the shelf. Once assembled, you can program the chips via USB, with no external hardware programmer required.

We’ve seen some other similar hardware before. Meanwhile, if you’re whipping up your own useful debug tools, don’t hesitate to drop us a line!

The Printing Of Pi

June 5, 2023 by 15 Comments

It really isn’t necessary, but there is some geek cred to learning pi to some bizarre number of digits. One way to do that is via a piem — a mnemonic device that is easy to remember and gives you the digits. Don’t know any? [Roni Bandini] has you covered with the PiemPi machine. It prints a random piem on a thermal printer and calculates each digit on the fly. You can watch the machine in action in the video below.

Unfortunately, the Raspberry Pi Zero inside doesn’t have enough language skills to ensure the thing makes sense, so you get word salad that may or may not have any real meaning. For example, [Roni] quotes astronomer [Sir James Jeans’] phrase: “How I want a drink, alcoholic, of course, after the heavy lectures involving quantum mechanics.” Before the advent of calculators, we always used: “May I have a large container of coffee today?” In each case, you count the number of letters in each word to get the digits. However, some of the piems you can see from the machine start off with phrases like: “# leon a yahoo execution im actual total pit eagle detector christmas…”

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This Vending Machine Is For The Birds

June 5, 2023 by 13 Comments

The early bird may get the worm, but [Stephen Chasey’s] birds only get to eat if they are smart. He’s created a vending machine for bird feeding. While this is a classic and simple exercise for a microcontroller, [Stephen’s] design is all op amps and 555 timers. The feeder comes on when it detects a warm body and waits for something to drop through a hole. Birds don’t have coins, so the hole will accept anything that will trigger the IR sensor within. In response, it dispenses a few peanuts. Rodents and squirrels won’t figure out the machinery, and so they can’t pilfer the peanuts meant for the pigeons — or other birds, even if they don’t start with the letter P.

A PIR sensor detects a warm body. A 555 keeps the system going for about 24 seconds after the last PIR event. Pairs of IR LEDs and phototransistors act as sensors that look through heat shrink tubing, which is, apparently, IR transparent. When a virtual coin drops through the hole, one of the sensors picks it up and starts another 555, which turns on a vibration motor. Another sensor watches for a nut to drop, which stops the motor. It also will time out after 11 seconds.

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Secret Bookshelf Door Uses Hidden Fingerprint Scanner

May 30, 2023 by 4 Comments

What is it that compels us about a secret door? It’s almost as if the door itself and the promise of mystery is more exciting than whatever could lay beyond. In any case, [Scott Monaghan] is a lover of the form, and built his own secret door hidden in a bookshelf, as all good secret doors should be.

The door is activated by pulling down on the correct book. This then reveals a fingerprint scanner. Upon presenting the right digit, the door will elegantly swing open to reveal the room beyond. Secret door experts will note there’s an obvious tell due to the light spilling through the cracks, however [Scott] reports that the finishing stages of the build solved this issue. The door was also fitted with a manual release for easier daily use.

Details are light, but the basics are all there. Really all you need is a cheap hardware store door opener, a secret activation lever or authentication method, and a well-hinged bookcase to achieve this feat yourself. We’ve seen some other great secret doors before, too. Video after the break.

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