Salvaged Scope Lets You Watch the Music

Everyone likes a good light show, but probably the children of the 60s and 70s appreciate them a bit more. That’s the era when some stereos came with built-in audio oscilloscopes, the search for which led [Tech Moan] to restore an audio monitor oscilloscope and use it to display oscilloscope music.

If the topic of oscilloscope music seems familiar, it may be because we covered [Jerobeam Fenderson]’s scope-driving compositions a while back. The technique will work on any oscilloscope that can handle X- and Y-axis inputs, but analog scopes make for the best display. The Tektronix 760A that [Tech Moan] scrounged off eBay is even better in that it was purpose-built to live in an audio engineer’s console for visualizing stereo audio signals. The vintage of the discontinued instrument isn’t clear, but from the DIPs and discrete components inside, we’ll hazard a guess of early to mid-1980s.  The eBay score was a bargain, but only because it was in less that perfect condition, and [Tech Moan] wisely purchased another burned out Tek scope with the same chassis to use for spares.

The restored 760A does a great job playing [Jerobeam]’s simultaneously haunting and annoying compositions; it’s hard to watch animated images playing across the scope’s screen and not marvel at the work put into composing the right signals to make it all happen. Hats off to [Tech Moan] for bringing the instrument back to life, and to [Jerobeam] for music fit for a scope.

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Controlling Your Instruments From A Computer: Doing Something Useful

Do you know how to harvest data from your bench tools, like plotting bandwidth from your oscilloscope with a computer? It’s actually pretty easy. Many bench tools make this easy using a standard protocol with USB to make the connection.

In the previous installment of this article we talked about the National Instruments VISA (Virtual Instrument Software Archetecture) standard for communicating with your instruments from a computer, and introduced its Python wrapper with a simple demonstration using a Raspberry Pi. We’ll now build on that modest start by describing a more useful application for a Raspberry Pi and a digital oscilloscope; we’ll plot the bandwidth of an RF filter. We’ll assume that you’ve read the previous installment and have both Python and the required libraries on your machine. In our case the computer is a Raspberry Pi and the instrument is a Rigol DS1054z, but similar techniques could be employed with other computers and instruments.

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Soviet Portable Scopemeter Teardown

Browsing YouTube may prove to be your largest destroyer of productive time outside of Hackaday, once you have started looking at assorted Lincolnshire plumbers or young Ukrainians doing dangerous stunts it’s easy to lose an hour with very little to show for it. There is so much to divert our attention, it’s a wonder that any of us ever make anything!

So to ensure you lose a further quarter hour today, we’d like to bring you [Jesper Broe]’s demonstration and teardown of his latest oscilloscope. This might seem unpromising when we tell you it’s a single-trace model with a bandwidth of 10MHz, but don’t give up. This is a RIMEDA C1-112, a portable instrument made in Lithuania when the country was part of the Soviet Union, and its party piece is that it contains a digital multimeter with a vector display using the oscilloscope CRT.

We’re shown the compact device being unpacked, then put through its paces as an oscilloscope. It gives useful results above 10MHz, but it is visibly losing amplitude and eventually it has trouble triggering as the frequency increases. Interestingly all the controls work in the opposite direction to the ones you will be used to, anticlockwise rotation increases rather than decreases. Then we’re shown the multimeter function, which is compared to a modern DMM and found to be still pretty accurate after nearly three decades.

The ‘scope’s lid is then removed, and we see something of the logic boards that produce the digital display. A host of Soviet K155 series logic ICs are at the heart of it, and at the end of the video we’re shown a period review in Russian with a glimpse at the waveforms they produce to vector draw the figures.

Take a look at the video below the break, we’re sure you’ll agree it’s an instrument that many of us would still find useful today.

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Build Your Own EMI Probes

[Gerald Musy] wanted to investigate the source of electromagnetic interference (EMI) in his switching power supply design. Stymied by the high cost of EMI probes, he decided to build his own. Lucky for us, he wrote up his results of experimenting with four different designs.

The probes include an unshielded loop, a shielded loop, a ferrite core probe, and an electric field probe. None of these are especially complex to build–the ferrite core one is probably the most involved–you can see from the scope traces that the different probes pick up different information.

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Scrap Bin Mods Move Science Forward

A first-time visitor to any bio or chem lab will have many wonders to behold, but few as captivating as the magnetic stirrer. A motor turns a magnet which in turn spins a Teflon-coated stir bar inside the beaker that sits on top. It’s brilliantly simple and so incredibly useful that it leaves one wondering why they’re not included as standard equipment in every kitchen range.

But as ubiquitous as magnetic stirrers are in the lab, they generally come in largish packages. [BantamBasher135] needed a much smaller stir plate to fit inside a spectrophotometer. With zero budget, he retrofitted the instrument with an e-waste, Arduino-controlled magnetic stirrer.

The footprint available for the modification was exceedingly small — a 1 cm square cuvette with a flea-sized micro stir bar. His first stab at the micro-stirrer used a tiny 5-volt laptop fan with the blades cut off and a magnet glued to the hub, but that proved problematic. Later improvements included beefing up the voltage feeding the fan and coming up with a non-standard PWM scheme to turn the motor slow enough to prevent decoupling the stir bar from the magnets.

[BantamBasher135] admits that it’s an ugly solution, but one does what one can to get the science done. While this is a bit specialized, we’ve featured plenty of DIY lab instruments here before. You can make your own peristaltic pump or even a spectrophotometer — with or without the stirrer.

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Partsbox.io Wants to Organize Your Junk Box

There are many ways to divide the hacker community into groups. Tubes vs transistors. Emacs vs VI, microcontroller vs discrete component designers. However, one of the more fundamental divisions in the community is how you organize your parts. We’ve seen giant warehouses with carefully organized bins and cabinets full of components, and we’ve seen storage crates with tangles of wires and bits of electron-bending components scattered among the wires.

dbIf you are in the former camp, you’d probably enjoy partsbox.io (see image, right). If you are in the latter group, you probably need to check it out even more than the other people. The idea is simple: an online place to keep an inventory of your electronic parts. The implementation is not as simple, though. The web application will work on a mobile device or just about anywhere. You can view your components by type, by location (the shoe box under the bed vs the parts bin in the closet), or by a project’s bill of materials. You can use “known” parts or create private parts for things no one else has (for example, your custom PC boards, or those 3D printed brackets you made to hold a microswitch). If you add data for a component you can make it available to other users.

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A DIY Vacuum Pickup Tool for $75

If you’re assembling prototypes of SMD boards on your own, placing the parts accurately can be a pain. Of course, it’d be nice to have a full pick and place machine, but those are rather expensive and time consuming to set up, especially for a small run of boards. Instead, a vacuum pickup tool can help you place the parts quickly and accurately by hand.

The folks over at Ohmnilabs have put together their own DIY pickup tool for about $75, and it’s become part of their in-house prototyping process. They grew tired of placing components with tweezers, which require you to remove parts from the tape before lifting them, and have a tendency to flip parts over at the worst time.

The build consists of a couple parts that can be bought from Amazon. An electric vacuum pump does the sucking, and the vacuum level is regulated with an adjustable buck converter. A solid foot switch keeps your hands free, and syringe tips are used to pick the parts up.

This looks like a simple afternoon build, but if you’re prototyping, it could save you tons of time. To see it in action, check out the video after the break.

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