oscilloscope

Touchscreen Oscilloscope

August 8, 2017 by 3 Comments

[Marco Reps] didn’t want to lug a full-sized oscilloscope around to measure his ECG while running. He decided to check out the DSO112A which is a tiny touchscreen scope from the usual China sources. The tiny one channel scope can go to 2mV/division at 2MHz and can save and recall up to 24 configurations. It also has access to the data via a serial port so you can use it as a fancy data logger. [Marco’s] video appears below.

Apparently, there is was an older model without the A on the end that was not as sensitive and had some other missing features. The price is about $70–fairly inexpensive, although not throw-away cheap.

[Marco] noted that one of the two small connectors can act as an external trigger input or a function generator. There’s the typical LiPo battery inside and a shielded input section. [Marco] tears the board down and looks at the chips on the board. Inside are two Atmel CPUs and a 20 megasample per second analog to digital converter.

The color screen looks surprisingly good in the video although, as [Marco] points out, with one channel, the colors aren’t super useful. The device also has cursors and a nice selection of measurements that work both live and on stored data.

At the end of the video, [Marco] shows a simple ECG amplifier he built from an open source schematic. We’ve covered simple ECG circuits before if you want to read more.

Last year we looked at two small inexpensive scopes. Like everything else, each year the bar gets higher. Although, in fairness, those scopes had a (reported) 25 MHz bandwidth. We’d love to see that kind of front end with the user interface of the DSO112A.

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Dual Trace Scope 1939 Style

July 10, 2017 by 20 Comments

If you buy a serious scope these days, it is a good bet it will have at least two channels. There is a lot of value to being able to see two signals in relation to one another at one time. Even though the dual-trace oscilloscope goes back to 1938, they were uncommon and expensive for many years. [Mr. Carlson] found a device from 1939 that would turn a single channel scope into a dual trace scope. In 1939, that was quite the engineering feat.

Today, a dual trace scope is very likely to be digital. But some analog scopes used CRTs with multiple beams to actually draw two traces on the same screen. Most, however, would draw either one trace followed by the other (alternate mode) or rapidly switch between channels (chopper mode). This Sylvania type 104 electronic switch looks like it takes the alternate approach, switching between signals on each sweep using vacuum tubes. You can see the device in action in the video, below.

The inputs and outputs of the device are just simple binding posts, but the unit looked to be in good shape except for the power cord. [Mr. Carlson] does a teardown and he even traced out a hand-drawn schematic. Fair warning. The video is pretty long. If you want to get right to the switch actually driving a scope, that’s at about one hour and seven minutes in.

We doubt we’ll see a tube-based Quake game anytime soon. If you want to get into restoring old tube-based gear yourself, you could do worse than read about radio restoration.

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Hackaday Prize Entry: Oscilloscope for the Masses

June 15, 2017 by 38 Comments

If you head down to your local electronics supply shop (the Internet), you can pick up a quality true-RMS multimeter for about $100 that will do almost everything you will ever need. It won’t be able to view waveforms, though; this is the realm of the oscilloscope. Unlike the multimeter’s realistic price point, however, a decent oscilloscope is easily many hundreds, and often thousands, of dollars. While this is prohibitively expensive for most, the next entry into the Hackaday Prize seeks to bring an inexpensive oscilloscope to the masses.

The multiScope is built by [Vítor] and is based on the STM32-O-Scope which is built around a STM32F103C8T6 microcontroller. This particular chip was chosen because of its high clock speed and impressive analog-to-digital resolution, which are two critical specifications for any oscilloscope. This particular scope has an inductance meter built-in as well, which is another feature which your otherwise-capable multimeter probably doesn’t have.

New features continue to get added to this scope by [Vítor]. Most recently he’s added features which support negative voltages and offsets. His particular scope is built inside of a model car, too, but we believe this to be an optional feature.

FPGA Rescues Scope From The Dumpster

June 1, 2017 by 60 Comments

I’m always on the lookout for a quality addition to my lab that would respect my strict budget. Recently, I’ve found myself pushing the Hertz barrier with every other project I do and hence desperately wanted a high bandwidth scope. Unfortunately, only recently have 70 MHz to 100 MHz become really affordable, whilst a new quad channel oscilloscope in the 500 MHz to 1 GHz range still costs a fortune to acquire. My only option was to find an absolute miracle in the form of an old high bandwidth scope.

It seemed the Gods of Hand Me Down electronics were smiling upon me when I found this dumpster destined HP 54542C. It appeared to be in fairy good shape and was the Top Dog in its day. But something had to be broken right? Sure enough, the screen was clearly faulty and illegible. Want to know how I fixed it? Four letters: FPGA.

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Scope Review: Keysight 1000 X-Series

May 2, 2017 by 69 Comments

A few weeks ago we published an article on the newly released Keysight 1000X, an oscilloscope that marks Keysight’s late but welcome entry into the hacker-centric entry-level market. Understandably, this scope is causing a lot of excitement as it promises to bring some of the high-end pedigree of the well-known 2000X and 3000X models down to a much affordable price. Now couple that with the possibility of hacking its bandwidth lock and all this fuss is well justified.

[Dave Jones] from the EEVblog got his hands on one, and while conducting a UART dump saw the scope report 200 MHz bandwidth despite being labelled as a 100 MHz model. He then proceeded to actually hack the main board to unlock an undocumented 200 MHz bandwidth mode. This created a lot of confusion: some said [Dave] got a “pre-hacked” version, others assumed all 100 MHz versions actually have a stock bandwidth of 200 MHz.

Alongside the question of bandwidth, many wondered how this would fare against the present entry-level standard, the Rigol 1054Z. Is the additional cost and fewer channels worth the Keysight badge?

Keysight’s response to our queries and confusion was the promise to send us a review unit. Well, after receiving it and playing around with it, clearly a lot of Keysight’s high-end excellence has trickled down to this lower end version. However, this machine was not without some silly firmware issues and damning system crashes! Read on the full review below. Continue reading “Scope Review: Keysight 1000 X-Series” →

Restoring a Japanese Oscilloscope

May 2, 2017 by 5 Comments

Oscilloscopes have come a long way. Today’s scope is more likely to look like a tablet than an old tube-based instrument. Still, there’s something about looking into a glowing green tube, especially if you’ve done the work to resurrect that old hollow state device. [NFM] picked up a Kikusui OP-31C–a vintage Japanese scope at a second-hand store. He made a video of his restoration efforts that you can see below.

The scope actually powered up and worked the first time. Of course, unlike a modern scope, the OP-31C has to warm up before it will show up. However, the pots needed cleaning and as a precaution, he replaced the old oil and electrolytic capacitors.

The big transformer and the coarse-looking single sided circuit board certainly will bring back memories if you are old enough. [NFM] had a schematic of the scope and takes you on a tour of the innards, although his schematic had some subtle differences from the actual unit, possibly due to some repair work.

He was going to rebuild one of the large electrolytic “can” capacitors to keep the outer shell with newer (and smaller) modern capacitors. However, he found a very similar modern capacitor and used that, instead.

We think it would have been more fun if the scope didn’t work. However, it was still a great tear down of the old tube-based device. This is a bigger device than the last old scope tear down we looked at. Not that we haven’t seen smaller ones (although, the link in the post has moved).

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