Your Next Oscilloscope Might Be Optical

December 19, 2021 by Al Williams 12 Comments

What’s better than a 100MHz scope? How about an optical one? Researchers at the University of Central Florida think that’s just the ticket, and they’ve built an oscilloscope that can measure the electric field of light. You can find the full paper online.

Reading the electrical field of light is difficult with traditional tools because of the very high frequency involved. According to [Michael Chini], who worked on the new instrument, the oscilloscope can be as much as 10,000 times faster as a conventional one.

The measurement of a few cycles of light requires some special techniques as you might expect. According to the paper:

[A]n intense fundamental pulse with a central wavelength of 3.4 µm creates charge packets in the pixels of a silicon-based image sensor via multiphoton excitation, leading to detectable photocurrents. The probability of excitation is perturbed by the field of a weak perturbation pulse, leading to a modulation in the excitation probability and therefore in the magnitude of the detected photocurrent. We have previously shown that, for collinear fundamental and perturbation pulses, the dependence of the modulation in the excitation probability on the time delay between the two pulses encodes the time-varying electric-field waveform of the laser pulse. Here, by using a crossed-beam geometry with cylindrical focusing, we map the time delay onto a transverse spatial coordinate of the image sensor chip to achieve single-shot detection.

Did you get that? In other words, instead of measuring the light pulse directly, they measure the change it makes on another known signal. We think…

Unless you’re moving high-speed data across fiber optic, we aren’t sure you really need this. However, the concept is intriguing and not previously unheard of. For example, we’ve seen capacitance meters that measure the change in frequency caused by adding an unknown capacitor into an existing oscillator.

If you want something more conventional, maybe look at some popular scopemeters. Of course, something this high speed might be able to apply time-domain reflectometry to fiber optics. Maybe.

3D Printing A Cyclonic Dust Separator

December 17, 2021 by Lewin Day 20 Comments

[rctestflight] recently purchased a big CNC router, and that meant it was time to arrange for some dust extraction in the workshop. Naturally, he set about building this himself!

Using a shop vac is fine at smaller scales, but they can quickly be filled up on bigger jobs. To stop it getting filled up as quickly and wasting vacuum bags, [rctestflight] wanted to build a 3D-printed cyclonic separator to catch and dump the heavier-than-air particles from the routing process into an attached bucket.

[rctestflight] trialed a variety of designs, from a quad cyclone, to a large single cyclone and even a triple-series design. A diffuser design was also built, that aims to slow the air flow to the point where particles drop out of the air stream. At the end of the day, the large mono-cyclone design proved to be the most effective at removing particles from the airstream.

Fundamentally, if you’re making lots of dust, a cyclonic separator is a great way to go about dealing with the problem. We’ve seen similar builds scaled up to deal with the needs of a whole workshop, too. Video after the break.

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Simple Mods Turn 3D Printer Into Electrochemical Metal Cutter

December 17, 2021 by Dan Maloney 30 Comments

We’re not aware of any authoritative metrics on such things, but it’s safe to say that the Ender 3 is among the most hackable commercial 3D printers. There’s just something about the machine that lends itself to hacks, most of which are obviously aimed at making it better at 3D printing. Some, though, are aimed in a totally different direction.

As proof of that, check out this Ender 3 modified for electrochemical machining. ECM is a machining process that uses electrolysis to remove metal from a workpiece. It’s somewhat related to electric discharge machining, but isn’t anywhere near as energetic. [Cooper Zurad] has been exploring ECM with his Ender, which he lightly modified by replacing the extruder with a hypodermic needle electrode. The electrode is connected to a small pump that circulates electrolyte from a bath on the build platform, while a power supply connects to the needle and the workpiece. As the tool traces over the workpiece, material is electrolytically removed.

The video below is a refinement of the basic ECM process, which [Cooper] dubs “wire ECM.” The tool is modified so that electrolyte flows down the outside of the needle, which allows it to enter the workpiece from the edge. Initial results are encouraging; the machine was able to cut through 6 mm thick stainless steel neatly and quickly. There does appear to be a bit of “flare” to the cut near the bottom of thicker stock, which we’d imagine might be mitigated with a faster electrolyte flow rate.

If you want to build your own Ender ECM, [Cooper] has graciously made the plans available for download, which is great since we’d love to see wire ECM take off. We’ve covered ECM before, but more for simpler etching jobs. Being able to silently and cleanly cut steel on the desktop would be a game-changer.

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DIY Mechanical Flux Dispenser Syringe Has Fine Control

December 17, 2021 by Donald Papp 16 Comments

[Perinski]’s design for a mechanical flux dispenser uses some common hardware and a few 3D printed parts to create a syringe with fine control over just how much of the thick stuff gets deposited. The design is slick, and there’s a full parts list to accompany the printed pieces. [Perinski] even has some useful tips on how to most effectively get flux into 5 mL syringes without making a mess, which is a welcome bit of advice.

There is also a separate companion design for a magnetic syringe cap. Not only does it have an O-ring to keep things sealed and clean, but the tip of the cap has a magnet embedded into it, so that it can be stowed somewhere safe while the dispenser is in use, and doesn’t clutter the workspace.

This is all a very interesting departure from the design of most syringe dispensers for goopy materials, which tend to depend on some kind of pneumatic action. Even so, we’ve also seen that it’s possible to have a compact DIY pneumatic dispenser that doesn’t require a bulky compressor.

If you can’t quite figure out how the ergonomics of [Perinski]’s design are intended to work one-handed, you’re not alone. One holds the syringe in their hand, and turns the large dial in small increments with a thumb to control extrusion. [Perinski] demonstrates it close-up around the 4:50 mark, but if you have a few minutes it is worth watching the entire video, embedded below.

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Motorized Device Helps Swap Out Hard-To-Reach Light Bulbs

December 16, 2021 by Lewin Day 27 Comments

High ceilings can make a residence feel open and airy, but they often come with difficult-to-reach light fittings. To better deal with that, [mattwach] built a motorized light bulb changer which makes the job much easier.

Light bulb changers already exist, but they typically need to be used on-axis with the light fitting, which for chandeliers and many other lights, can be difficult. Instead, [mattwach’s] design allows the device to be used at 90-degree angles, and motorizes it for added ease of use.

A 12V gear motor does the work of turning the contraption, and has more than enough torque to get the job done. A flanged coupling is used to attach the motor to the light bulb changer itself. An ATTiny85 microcontroller is then used to control the motor via an L293D H-bridge driver. A PS2 thumbstick is hooked up for user input, and all the electronics is mounted on a broomstick along with the light bulb end effector mounted at a right angle.

Changing a bulb is then as simple as slipping the end effector over a bulb, and flicking the thumbstick in the direction to unscrew the light. It can then be removed, and then replaced with a fresh bulb, screwed in by pushing the thumbstick in the other direction.

Normally, such a task would be quite a sketchy proposition when done on the top of a tall ladder. Instead, it becomes an easy job done from the safety of an overlooking walkway, completed in less than half an hour when changing a full 15-bulb chandelier.

Incidentally, if you’re swapping out your bulbs, you might be interested in the special royal lights you’re not allowed to buy. Video after the break.

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Using Fishing Wire To Hold In Pin Headers Is A Nifty Trick

December 16, 2021 by Lewin Day 55 Comments

Working on a breadboard, one can get used to the benefits of being able to readily plug and unplug jumper wires to reconfigure a project. One could only dream of doing so with PCBs, right? Wrong! [Stewart Russell] recently shared a tip on Twitter on how to do just that, with the help of a little fishing wire.

The wire can be neatly threaded through the board to enable quick hookups.

The trick is simple: on any old development board that uses 0.1″ pitch headers, simply weave some fishing line through the plated through-holes in the PCB. Then, regular jumper wires can be inserted just like on a breadboard. The fishing wire has just enough give to allow the jumper wires to be jammed in, holding them steady and in good contact, while still allowing them to be easily removed.

[Hackspace Magazine] has raved about the trick, noting great success using 0.38 mm fishing line. Alternative methods involve using toothpicks, though we suspect solution is likely messier and less reliable.

If you’ve got your own tricks for prototyping quickly using development and breakout boards, be sure to share them below in the comments. Alternatively, send your best stuff to us on the tipsline!

DIY Semi Auto Grinder Builds Itself (Sort Of)

December 14, 2021 by Dave Rowntree 12 Comments

[JSK-koubou] is no stranger to making tools to improve their work, and this latest video is yet another in a long list of such builds, just checkout their YT channel to see the many other examples. The tool being highlighted this time is a semi-automatic grinder (Video, embedded below) which could be very handy in many situations.

Many of us struggle a little to get straight cuts with an angle grinder, especially with softer materials, as it is sometimes hard to get a good ‘feel’ of how the cut is proceeding. Once the cut is started, thin blades will tend to ‘track’ in the slot, so if it starts off a little bit, the whole cut will be off. Most annoying. Anything to help keep things straight and square would help a lot, with the extra feature of a motorized drive enabling a constant cut rate, and presumably giving an increase in the cut quality.

Using the part completed rig to cut its own leadscrew

Since operation is hands-off, you could set it up, and leave it to do its thing, whilst you step aside, away from flying sparks, noise and the remote possibility of getting a splintered blade in your face, should the unthinkable happen. All good things.

The detailed build video shows what looks like a pretty solid construction, there are plans available on the accompanying website, but they do request a small donation of ¥1000 (less than $10 USD) to download them. Given the usefulness of the tool, this seems like a small price to pay. We quite liked some sections of the build video, where the tool is used to cut its own components, as it is built-up sequentially. Clever stuff! Another interesting technique to see was the use of a flame-heated (Stanley) knife blade as a drive belt end-jointer. Somewhat tough on the blade, but it’s a consumable item and gets the job done, so that’s good enough for us!

Parts wise, there’s nothing special at all here, with most easily sourced via the usual mechanical suppliers, but we reckon you’d be able to find most of it on eBay as well. We think this is exactly the sort of build that would work well in your local Makerspace, so perhaps give that a thought?

Bored with manually cutting off? Need an overkill solution for a mundane job? How about an Automatic Cut-Off Saw? If you need some defense against the mighty angle grinder, then perhaps Proteus is just the ticket?

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