Modern Control Of A Logic Analyzer

December 27, 2023 by 8 Comments

When you think of a logic analyzer today, you might think of a little USB probe that can measure a few signals and decoding for various serial buses. But actual logic analyzers were high-speed multichannel hardware with sophisticated ways to clock and trigger. [Tom] picked up an HP1670G on the surplus market and was impressed that it could sample 136 channels at 500 MHz. The circa-2000 machine has a front panel, but if you really wanted to use it, you wanted to use an X terminal. [Tom] shows us how that works with modern Linux software.

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Second Life UPS Mark II: A UPS For Low-Voltage DC Applications

December 17, 2023 by 17 Comments

When you have a whole stack of devices and appliances that all have an AC to DC adapter and which you’d like to put on an uninterruptable power supply (UPS), you could do the obvious thing and get an off-the-shelf UPS with myriad AC outputs. In the case of a 19″ rack this means wrangling a power strip or two and any combination of differently sized AC/DC adapters into the rack, with questionable efficiency and waste heat dumped into the rack. This is where a DC-only UPS like [Maciej Grela]’s Second Life UPS Mark II provides an interesting alternative.

At its core it’s a pretty simple concept: A single 400Watt power supply handles the AC/DC conversion from mains to 24 VDC, which feeds the battery charger as well as the outputs. These outputs include 5 VDC, 12 VDC and Vrail, with the latter being either the output from the PSU, or the battery voltage. In case of AC power failure, an LT4416 dual power path controller handles the switch-over from the PSU output to the internal batteries. In the article, [Maciej] covers how the buck modules for the 12 & 5 VDC rails were sized, along with the conversion of an old rack-mounted network switch into a UPS. Continue reading “Second Life UPS Mark II: A UPS For Low-Voltage DC Applications” →

How To Talk To Your Scope

November 21, 2023 by 21 Comments

It used to be only high-end test equipment that had some sort of remote control port. These days, though, they are quite common. Historically, test gear used IEEE-488 (also known as GPIB or, from the originator, HPIB). But today, your device will likely talk over a USB port, a serial port, or a LAN connection. You’d think that every instrument had unique quirks, and controlling it would be nothing like controlling another piece of gear, especially one from another company. That would be half right. Each vendor and even model indeed has its unique command language. There has been a significant effort to standardize some aspects of test instrument control, and you can quickly write code to control things on any platform using many different programming languages. In a few posts, I will show you just how easy it can be.

The key is to use VISA. This protocol is defined by the IVI Foundation that lets you talk to instruments regardless of how they communicate. You do have to build an address that tells the VISA library how to find your device. For example: “TCPIP::192.168.1.92::INSTR.” But once you have that, it is easy to talk to any instrument anywhere.

I say that thinking it is a problem is half right because talking to the box is one task of the two you need to complete. The other is what to say to the box and what it will say back to you. There are a few standards in this area, but this is where you get into problems. Continue reading “How To Talk To Your Scope” →

Hands On With Boondock Echo

November 10, 2023 by 23 Comments

Perhaps no words fill me with more dread than, “I hear there’s something going around.” In my experience, you hear this when some nasty bug has worked its way into the community and people start getting whatever it is. I’m always on my guard when I hear about something like this, especially when it’s something really unpleasant like norovirus. Forewarned is forearmed, after all.

Since I work from home and rarely get out, one of the principal ways I keep apprised of what’s going on with public health in my community is by listening to my scanner radio. I have the local fire rescue frequencies programmed in, and if “there’s something going around,” I usually find out about it there first; after a half-dozen or so calls for people complaining of nausea and vomiting, you get the idea it’s best to hunker down for a while.

I manage to stay reasonably well-informed in this way, but it’s not like I can listen to my scanner every minute of the day. That’s why I was really excited when my friend Mark Hughes started a project he called Boondock Echo, which aims to change the two-way radio communications user experience by enabling internet-backed recording and playback. It sounded like the perfect system for me — something that would let my scanner work for me, instead of the other way around. And so when Mark asked me to participate in the beta test, I jumped at the chance.

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Creating A New Metal Rohde & Schwarz EB200 Miniport Receiver Dial Knob

October 30, 2023 by 6 Comments

Recently [Roberto Barrios] got his hands on a Rohde & Schwarz EB200 monitoring and surveillance receiver that, despite its late 90s vintage, was in mint condition. Aside from damage to the main dial, that is, which was very much broken. With no off-the-shelf replacement available in 2023, the obvious answer was to get a close-enough dial knob with the rough proportions and use a lathe to machine it into shape. Initially, [Roberto] had used some filler material to replace the front of the original knob that was missing, but this was a decidedly inferior tactile experience with questionable long-term reliability.

Dimensions of the Rhode & Schwarz EB200 dial knob. (Credit: Roberto Barrios)
Dimensions of the Rhode & Schwarz EB200 dial knob. (Credit: Roberto Barrios)

The challenge in replacing the original knob with a proper replacement was in how the dial knob is mounted on the receiver, as an internally threaded shell that goes on the internal dial encoder assembly. With a lathe at his behest, taking an off-the-shelf dial knob that accepts a 6 mm shaft and turning it into a compatible knob was a straightforward affair. Removing the excess material and creating the internal 1 mm pitch thread allowed the newly made knob to fit on the receiver like an OEM part. The only niggle was having to remove 1.8 mm off the face of the brass body to get the knob to sit close to the front panel.

Unlike the old patched-up knob, this new one is fully out of metal and has the absolutely essential feature of the recessed area for easy fine-tuning. Although perhaps not the most exciting fix for old gear, it’s decidedly essential to keep it functional.

PC Case Makes Portable Power Supply

October 21, 2023 by 4 Comments

Recently, we’ve seen a lot of semi-portable power stations. These have some big rechargeable battery and various connection options. [Dereksgc] wanted to make his own and decided the perfect housing would be a small PC tower case. (Video, embedded below.) It makes sense. There are plenty of easy-to-work front panel inserts, a power supply box with an AC cord (the power supply is long gone), and it is big enough to fit the battery. You can see the result in the video below.

The bulk of the work was installing power supply modules and a charge controller on floppy disk blank panels. The battery — a 50 Ah LiFePO4 unit — fits nicely in the bottom. Some of the buttons and connectors find use in the new incarnation.

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2023 Hackaday Supercon Badge: Welcome To The Vectorscope

October 18, 2023 by 48 Comments

This year, the Supercon badge goes analog! (Or at least fakes it pretty convincingly.) Taking inspiration from the phosphor scopes of yesteryear, the 2023 Vectorscope badge is part analog audio playground, part art project, and all about prototyping. Who doesn’t like the warm glow and lovely green fade of an old Tektronix tube scope? That’s what we’re after.

Conceptually, the badge is two separate devices in one. Most obvious is the vectorscope, which takes in voltages in the 0 V – 3 V range and plots them out in X-Y mode in glorious fake-phosphor effect on the lovely round IPS screen. We’ve also tied an audio amplifier to the Y input that plays whatever waveform you’re watching.

But you don’t have to bring your own waveforms with you – the other half of the badge is an arbitrary programmable waveform generator that drives two channels. Off the bat, it’s configurable with the front panel controls, so you’re obviously invited to make Lissajous figures and store them in the program memories.

Combining the two halves lets you draw in voltages and time, but not until you connect them together, naturally. You see, this isn’t an analog simulation – it’s the programmable equivalent of the real deal, courtesy of the AK4619 ADC/DAC. Voltages go out on one set of pins and come back in on the other.

And you get to play around with these voltages in through-hole space too, because we’ve included a very generous prototyping board for your analog explorations. Does this instantly suggest a curve tracer to you? Be our guest! Other forms of analog video-mangling? We want to see what you come up with. Make an audio filter and watch it work on the screen in front of your very eyes.

Of course we’re not leaving you code monkeys out in the cold. MicroPython puts the “programming” in the programmable waveform generator. If you’re not content with the four stock waveforms, you’re invited to write your own. And this is where it gets artsy.

You can upload your own repetitive waveforms to the onboard direct digital synth routine, but why stop there? We’ve left most of the processing power of the underlying RP2040 untouched, for you to use. And four buttons on the front panel let you store and play back your code, so you have space to stash your demos, and a sweet joystick with a custom keycap gives you control.

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