Touchscreen Oscilloscope

[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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Oscilloscope Mod for the Blues

Roughly 8% of males and 0.6% of females are red-green color blind, and yet many common oscilloscopes use yellow and green for the traces for their two-channel readouts. Since [Roberto Barrios] is afflicted by deuteranopia, a specific form of red-green colorblindness that makes differentiating between yellow and green hard, if not impossible, he got to work hacking his Agilent oscilloscope to make it more colorblind friendly.

Starting with a tip from [Mike] from the EEVblog forums, [Roberto Barrios] set out to rewire the LCD interface and swap the red and green signals. That way yellow will turn bluish (red component replaced by blue) and it could be seen as “very different now” from the green trace on the readouts. Sounds simple right? Well, slight issue: the 0.5 mm pitch of the connector. He did not want to design a PCB and wait a few weeks to receive it, so he decided on using 0.1 mm wires held together with Kapton tape to route each signal individually from one connector to the other. After an hour under the microscope, it was done. And boy, his work is impressive, go check it out.

Voila! It worked splendidly. Now [Roberto Barrios] can use his scope. And, the stock UI is mostly grey or white, so swapping the red and blue channels did not change much the appearance of the interface. Moreover, the switch had a small unintentional bonus, the loading screen is much cooler now with an edgy red sky. Further, [Roberto Barrios] “would not be [himself] if [he] could resist changing the CH1 button backlight LED to blue, to match the new trace color. So, no [he] couldn’t.”

This was a well done and very functional oscilloscope mod, but if you need more frivolity in your life, fear not: we’ve got your back with real-time Quake played on an oscilloscope.

Hackaday Prize Entry: Oscilloscope for the Masses

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.

Restoring a Japanese Oscilloscope

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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Help Wanted: Open Source Oscilloscope on Rigol Hardware

We’ve often heard (and said) if you can’t hack it, you don’t own it. We noticed that [tmbinc] has issued a call for help on his latest project: developing new firmware and an FPGA configuration for the Rigol DS1054Z and similar scopes. It isn’t close to completion, but it isn’t a pipe dream either. [tmbinc] has successfully booted Linux.

There’s plenty left to do, though. He’s loading a boot loader via JTAG and booting Linux from the USB port. Clearly, you’d want to flash all that. Linux gives him use of the USB port, the LCD, the network jack, and the front panel LEDs and buttons. However, all of the actual scope electronics, the FPGA functions, and the communications between the processor and the FPGA are all forward work.

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Hacking a Vintage TV into an Oscilloscope

Do you still have an old analog CRT  television lying around? With the advent of digital signals, analog TV´s are going to the dumpster or the recycling center. But you can still put them to good use, just as [GreatScott!] did, by converting the TV into a crude oscilloscope.

The trick is to take control of the two deflection coils that move the electron beam inside the CRT in the horizontal and vertical directions. The video describes in detail the process of identifying the coils and using an Arduino nano in combination with a DAC to amplify the input signal in order to get the waveform in the TV screen. Step by step explanations and great editing make this project delightful to watch.

Even if you do not follow [GreatScott!]´s steps to build a simple oscilloscope, don´t throw away that vintage TV!, it is a great source of analog parts. The flyback transformer can be used to make a high voltage power supply, and you also get some nice high voltage capacitors (both electrolytic and mylar ones), the horizontal output transistor which is a high voltage one, ferrite transformers, magnet wire, plus a lot of other small parts. Other uses for old TV sets that you may want to try is to convert your TV into a gaming console, or  an audio synthesizer controlled by drawing with a light-sensitive pen on a CRT television.

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Jaw-Dropping, IC-Free Pong on an Oscilloscope

Pong may not be much anymore, but it’s the granddaddy of all video games, and there’s still a lot to learn by studying its guts. And what better way to do that than by having it all laid out before you as you play? All it takes is 200 discrete transistors and two large handfuls of passives tacked to a piece of copper clad board to get a version of Pong executed without a single chip that’s playable on an oscilloscope.

Clearly a labor of love, if not an act of temporary insanity, [GK]’s realization of Pong is a sight to behold. Every scrap of it is circuits of his own design, executed dead bug style, apparently because [GK] enjoys life on hard mode. The game itself is surprisingly playable and you can even play against the machine. The video below is a little hard to watch, what with some glare on the oscilloscope CRT, but we’ll cut [GK] plenty of slack on this one; after all, it looks like this whole project was pulled off in one marathon weekend build session.

We’re still busy poring over the hand-drawn Forrest Mims-style schematics, which by themselves are almost a complete course in analog design. A lot of the circuits remind us [GK]’s bouncing ball simulation, which we covered a while back.

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