Better Scope Measurements

There was a time when few hobbyists had an oscilloscope and the ones you did see were old military or industrial surplus that were past their prime. Today you can buy a fancy scope for about what those used scopes cost that would have once been the envy of every giant research lab. However, this new breed of instrument is typically digital and while they look like an old analog scope, the way they work leads to some odd gotchas that [Arthur Pini] covers in a recent post.

Some of his tips are common sense, but easy to forget about. For example, if you stack your four input channels so each uses up a quarter of the screen, it makes sense, right? But [Arthur] points out that you are dropping two bits of dynamic range, which can really jack up a sensitive measurement.

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Why Didn’t We Think Of Making A Remote Trigger Button?

One of the many functions a digital oscilloscope offers over its analog ancestors is a trigger button. Alongside the usual electronic means of triggering the instrument, you can reach over and press a button to “freeze-frame” the action and preserve the trace. Sometimes doing it repeatedly it can become a chore to reach for the ‘scope. That’s where [Kevin Santo Cappuccio]’s remote trigger button comes in.

The button itself is about as simple a hack as it gets. The ‘scope was carefully dissected and some fine wires laid from the contacts within the front panel to a connector on the case. From there a cable goes to a box with a momentary action button switch. Plug in the box, and you can trigger the ‘scope from a distance!

We have to admit to rather admiring this hack, as needing to trigger the ‘scope is a well-known problem here. It’s easy to stab the wrong button and lose what you are looking for, so we’re rather surprised we didn’t think of this one ourselves. But then again from another viewpoint, it involves dissecting an expensive instrument which is best left unmolested. Perhaps manufacturers should consider adding this functionality.

This may be the most straightforward oscilloscope hack we’ve shown you, but it’s certainly not the first.

Balancing A Motor With An Oscilloscope

With all things in life, one must seek to achieve balance. That may sound a little like New Age woo-woo, but if you think it’s not literally true, just try tolerating a washing machine with a single comforter on spin cycle, or driving a few miles on unbalanced tires.

Anything that rotates can quickly spin itself into shrapnel if it’s not properly balanced, and the DIY power tools in [Matthias Wandel]’s shop are no exception. Recent upgrades to his jointer have left the tool a bit noisy, so he’s exploring machine vibrations with this simple but clever setup. Using nothing but a cheap loudspeaker and an oscilloscope, [Matthias] was able to characterize vibrations in a small squirrel-cage blower — he wisely chose to start small to validate his method before diving into the potentially dangerous jointer. There was quite a lot to be learned from the complex waveforms coming back from the transducer, analysis of which was greatly helped by the scope’s spectrum analyzer function. The video below shows the process of probing various parts of the blower, differentiating spectral peaks due to electrical noise rather than vibration, and actually using the setup to dynamically balance the fan.

We’d rate this as yet another handy shop tip from [Matthias], and we’ll be looking out for the analysis of his jointer. Want to do the same but you don’t have an oscilloscope? No problem — an earbud and Audacity might be all you need.

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Cheap Oscilloscope Is… Well… Cheap

We always enjoy watching [Kerry Wong] put an oscilloscope through its paces. His recent video is looking at a very inexpensive FNIRSI 1014D ‘scope that you can also find rebranded. You can usually find these for well under $200 at the usual places. Can you get a reasonable scope for that cost? [Kerry] has a list of issues with the scope ranging from short memory depth to low sensitivity. He did, however, like that it is USB powered so it can be operated from a common battery pack, which would make it truly floating.

The ‘scope looks like a lot of other inexpensive ‘scopes, but you can see some concessions to price. For example, the encoder knobs don’t have a push button function, making the scope more difficult to operate. While the specs are relatively modest, [Kerry] wasn’t sure the instrument was even living up to them.

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Cute Oscilloscope Uses LEDs For Display

Oscilloscopes were once commonly called CROs, for the fact that they relied on cathode ray tubes for display. Since then, technology has moved quickly, and oscilloscopes these days almost entirely rely on modern screens like LCDs. However, [lonesoulsurfer] went a different route with this fun DIY build, creating an oscilloscope with a low-resolution LED display.

Yes, the signals are shown on a 10×10 matrix made up of red LEDs. The individual pixels look nicely diffused and chunky thanks to the fact that [lonesoulsurfer] was able to source square 5mm LEDs for the build. The whole project only uses four ICs – a decade counter and a LM3914 LED driver to run the display, a 555 timer for clock input, and an LM386 op-amp for amplifying incoming signals.

With a mic fitted onboard, the oscilloscope can act as a simple music visualizer, or be used with a probe to investigate actual circuits. It may not be of great enough resolution or precision for fine work, but it’ll at least tell you if your microcontroller’s clock is running properly if you’re scratching your head about the function of a simple project.

We’ve seen some great DIY oscilloscopes over the years, like this neat Arduino-based build. Video after the break.

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$60 PC Oscilloscope Review

Owning an oscilloscope is a real gamechanger and these days, scopes are more capable and less expensive than ever before. However, there is a big difference between scopes that cost several hundred dollars which are usually quite good and many of the very inexpensive — below $100 — instruments that are often — but not always — little more than toys. [Adrian] looks at a PC-based scope from Hantek that costs about $60. Is it a toy? Or a useful tool? He answers the question in the video below.

The Hantek 6022BE sports two channels with a 20 MHz bandwidth and 48 million samples per second. The device included probes, too. Of course, you also need a PC, although there is apparently third-party software for Android if you don’t want to lug a laptop around.

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[Kerry Wong] Is Really Into Scope Meters

If a combination multimeter and oscilloscope is on your holiday shopping list this year, you might want to have a look at some of [Kerry Wong’s] recent videos on the subject. Over several videos he looks at — inside and out — an OWON HDS272S and a Hantek 2D72, both reasonably inexpensive entries in the field. Both instruments are similar and have a few variants depending on the frequency capability and the addition of a waveform generator.

There are several videos on the Hantek device that are a few months old, then some recent videos — like the one below — on the OWON device along with some comparison videos.

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