oscilloscope

295 Articles

Incredibly Heavy Ornament Likely Inappropriate To Hang On Tree

December 20, 2018 by 6 Comments

It’s that time of year again, and the Christmas hacks are flooding in thick and fast. To get into the Christmas spirit,  the FoxGuard team wanted a custom ornament to hang from the tree. They may have gotten more than they bargained for.

It’s a simple build that demonstrates the basic techniques of working with DACs and scopes in a charming holiday fashion. A Tektronix T932A analog oscilloscope is pressed into service as a display, by operating in XY mode. A Teensy 3.5 was then chosen for its onboard digital to analog converters, and used to output signals to draw a Christmas tree and star on the screen.

Old-school coders will appreciate the effort taken to plot the graphics out on graph paper. While the hack doesn’t do anything cutting edge or wild, it’s impressive how quick and easy this is thanks to modern development methods. While the technology to do this has existed for decades, a hacker in 1998 would have spent hours breadboarding a PIC microcontroller with DACs, let alone the coding required. We’ve come a long way.

It’s a bit of fun, but we highly recommend you don’t try and hang an analog scope off your tree at home. These WiFi-controlled ornaments are perhaps more suitable. Video after the break. Continue reading “Incredibly Heavy Ornament Likely Inappropriate To Hang On Tree” →

Rigol MSO5000 Hacked, Features Unlocked

December 19, 2018 by 103 Comments

Rigol’s test gear has something of a history of being hacked. Years ago the DS1022C oscillocope was hacked to increase bandwidth, and more recently the DS1054Z was hacked to unlock licensed features. Now, it’s the MSO5000’s turn.

Over on the EEVBlog forums a group has been working on hacking another Rigol, the MSO5000, a 70 MHz oscilloscope which can be upgraded to 350 MHz via software licensing. Various other features including a two channel, 25 MHz arbitrary waveform generator are also built-in, but locked out unless a license key is purchased. The group have managed to enable all the locked options without license keys.

The hack is quite simple. The Linux system running on the scope has a default root password of, you guessed it, “root”. After logging in over SSH with these credentials, the user just needs to modify the startup file to add the “-fullopt” flag to the “appEntry” application. This starts the application in a fully unlocked state, which gives access to all the features.

The MSO5000 costs about $1000, and the bandwidth option alone adds over $3000 to the price. If you’re willing to risk your warranty, and you have the skills to edit a file with vi, this hack provides a serious upgrade for free.

If you have a DS1022C you’ll find our reporting on its hack here, and likewise DS1054Z owners will find theirs here.

Header image: EEVBlog.

My Oscilloscope Uses Fire

December 12, 2018 by 16 Comments

If you want to visualize sound waves, you reach for your oscilloscope, right? That wasn’t an option in 1905 so physicist [Heinrich Rubens] came up with another way involving flames. [Luke Guigliano] and [Will Peterson] built one of these tubes — known as a Rubens’ tube — and will show you how you can, too. You can see a video of their results, below. Just in case a flame oscilloscope isn’t enough to attract your interest, they are driving the thing with a theremin for extra nerd points.

The guys show a short flame run and one with tall flames. The results are surprising, especially with the short flames. Of course, the time base is the length of the tube, so that limits your measurements. The tube has many gas jets along the length and with a sound source, the height of the flames correspond to the air pressure from the sound inside the tube.

Continue reading “My Oscilloscope Uses Fire” →

The Guts Of Switched Mode Power Supplies, Brought To You By Oscilloscope Repair

December 8, 2018 by 22 Comments

The Tektronix 2000 series of oscilloscopes are a mainstay for any electronics lab. They work, they’re relatively cheap, they’re good, and they’re available in just about any surplus electronics store. [Mr.RC-Cam] has been hoarding one of these for twenty years, and like any classic piece of equipment, it needs a little refurbishment every now and again. Now, it’s time. Here’s how you repair one of the best values in analog oscilloscopes.

This repair adventure began when the scope died. There were no lights, no screen trace, and a brief hiss sound when it was powered on. (Ten points if you can guess what that hiss sound was!) Armed with a schematic, [Mr.RC-Cam] dove in and pulled the power supply, being careful to discharge the CRT beforehand.

There were no bulging capacitors, no obviously overheated components, and just a little bit of dust. The only solution was to look at the parts with a meter one at a time. Removing the big caps provided access to a row of diodes, which revealed the culprit: a single shorted diode. This part was ordered, and a few other housekeeping tasks were taken care of. The lithium battery on the processor board responsible for storing the calibration constants was replaced, and the new, smaller, caps got lovely 3D printed mounting flange adapters. Now, this old ‘scope works, and we’ve got a lovely story to tell around the electronic campfire.

High Voltage Measurement Is Shockingly Safe

November 17, 2018 by 9 Comments

With the right equipment and training, it’s possible to safely work on energized power lines in the 500 kV range with bare hands. Most of us, though, don’t have the right equipment or training, and should take great care when working with any appreciable amount of voltage. If you want to safely measure even the voltages of the wiring in your house there’s still substantial danger, and you’ll want to take some precautions like using isolated amplifiers.

While there are other safe methods for measuring line voltage or protecting your oscilloscope, [Jason]’s isolated amplifier method uses high voltage capacitors to achieve isolation. The input is then digitized, sent across the capacitors, and then converted back to an analog signal on the other side. This project makes use of a chip from TI to provide the isolation, and [Jason] was able to build it on a perfboard while making many design considerations to ensure it’s as safe as possible, like encasing high voltage sections in epoxy and properly fusing the circuit.

[Jason] also discusses the limitations of this method of isolation on his site, and goes into a lot of technical details about the circuit as well. It probably wouldn’t get a UL certification, but the circuit performs well and even caught a local voltage sag while he was measuring the local power grid. If this method doesn’t meet all of your isolation needs, though, there are a lot of other ways to go about solving the problem.

Cut Through The Noise, See Tiny Signals

November 1, 2018 by 18 Comments

An oscilloscope is a handy tool for measuring signals of all kinds, but it’s especially useful if you want to measure something with a periodic component. Modern oscilloscopes have all kinds of features built-in that allow you sample a wide range of signals in the hundreds of megahertz, and make finding and measuring your signal pretty easy, provided you know which buttons to push. There are some advanced oscilloscope methods that go beyond the built-in features of even the best oscilloscopes, and [AM] has a tutorial on one of them.

The method used here is called phase-senstitive detection, and allows tiny signals to be found within noise, even if the magnitude of the noise is hundreds of times greater than the signal itself. Normally this wouldn’t be possible, but by shifting the signal out of the DC range and giving it some frequency content, and then using a second channel on the oscilloscope to measure the frequency content of the source and triggering the oscilloscope on the second channel, the phase of the measured signal can be sifted out of the noise and shown clearly on the screen.

In [AM]’s example, he is measuring the intensity of a laser using a photodiode with a crude amplifier, but even with the amplifier it’s hard to see the signal in the noise. By adding a PWM-like signal to the power source of the laser and then syncing it up with the incoming signal from the photodiode, he can tease out the information he needs. It’s eally a fascinating concept, and if you fancy yourself a whiz with an oscilloscope this is really a tool you should have in your back pocket.  If you’re new to this equipment, we do have a primer on some oscilloscope basics, too.

Continue reading “Cut Through The Noise, See Tiny Signals” →

The Crystal (Testing) Method

October 20, 2018 by 19 Comments

It used to be any good electronics experimenter had a bag full of crystals because you never knew what frequency you might need. These days, you are likely to have far fewer because you usually just need one reference frequency and derive all the other frequencies from it. But how can you test a crystal? As [Mousa] points out in a recent video, you can’t test it with a multimeter.

His approach is simple: Monitor a function generator with an oscilloscope, but put the crystal under test in series. Then you move the frequency along until you see the voltage on the oscilloscope peak. That frequency should match the crystal’s operating frequency.

Continue reading “The Crystal (Testing) Method” →