Author: Dan Maloney

3259 Articles

A Compact SMD Reflow Hotplate Powered By USB-PD

January 9, 2024 by 10 Comments

When it comes to home-lab reflow work, there are a lot of ways to get the job done. The easiest thing to do perhaps is to slap a PID controller on an old toaster oven and call it a day. But if your bench space is limited, you might want to put this compact reflow hotplate to work for you.

There are a lot of nice features in [Toby Chui]’s build, not least of which is the heating element. Many DIY reflow hotplates use a PCB heater, where long, thin traces in the board are used as resistive heating elements. This seems like a great idea, but as [Toby] explains in the project video below, even high-temperature FR4 substrate isn’t rated for the kinds of temperatures needed for some reflow profiles. His search for alternatives led him to metal ceramic heaters (MCH), which are commonly found in medical and laboratory applications. The MCH he chose was rated for 20 VDC at 50 watts — perfect for powering with USB-PD.

The heater sits above the main PCB on a Kapton-wrapped MDF frame with a thermistor to close the loop. While it’s not the biggest work surface we’ve seen, it’s a good size for small projects. The microcontroller is a CH552, which we’ve talked about before; aside from that and the IP2721 PD trigger chip needed to get the full 60 watts out of the USB-PD supply, there’s not much else on the main board.

This looks like a nice design, and [Toby] has made all the design files available if you’d like to give it a crack. Of course, you might want to freshen up on USB-PD before diving in, in which case we recommend [Arya]’s USB-PD primer.

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Darkroom Robot Automates Away The Tedium Of Film Developing

January 8, 2024 by 14 Comments

Anyone who has ever processed real analog film in a darkroom probably remembers two things: the awkward fumbling in absolute darkness while trying to get the film loaded into the developing reel, and the tedium of getting the timing for each solution just right. This automatic film-developing machine can’t help much with the former, but it more than makes up for that by taking care of the latter.

For those who haven’t experienced the pleasures of the darkroom — and we mean that sincerely; watching images appear before your eyes is straight magic — film processing is divided into two phases: developing the exposed film from the camera, and making prints from the film. [kauzerei]’s machine automates development and centers around a modified developing tank and a set of vessels for the various solutions needed for different film processes. Pumps and solenoid valves control the flow of solutions in and out of the developing tank, while a servo mounted on the tank’s cover gently rotates the reel to keep the film exposed to fresh solutions; proper agitation is the secret sauce of film developing.

The developing machine has a lot of other nice features that really should help with getting consistent results. The developing tank sits on a strain gauge, to ensure the proper amount of each solution is added. To avoid splotches that can come from using plain tap water, rinse water is filtered using a household drinking water pitcher. The entire rig can be submerged in a heated water bath for a consistent temperature during processing. And, with four solution reservoirs, the machine is adaptable to multiple processes. [kauzerei] lists black and white and C41 color negative processes, but we’d imagine it would be easy to support a color slide process like E6 too.

This looks like a great build, and while it’s not the first darkroom bot we’ve seen — we even featured one made from Lego Technics once upon a time — this one has us itching to get back into the darkroom again.

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Hackaday Links: January 7, 2024

January 7, 2024 by 27 Comments

Oh, perfect — now our cars can BSOD. At least that’s how it looks from a forum post showing a Blue Screen of Death on a Ford Mustang Mach E, warning that an over-the-air software update failed, and now the car can’t be driven. The BSOD includes a phone number to reach Ford’s Customer Relationship Center and even presents a wall of text with specific instructions to the wrecker driver for loading the bricked vehicle onto a flatbed. Forum users questioned the photo’s veracity, but there are reports of other drivers getting bricked the same way. And we’ve got to point out that even though this specific bricking happened to an EV, it could just have easily happened to an ICE vehicle too; forum members were particularly prickly about that point. It would be nice if OTA software updates on vehicles could always roll back to the previous driveable state. Still, we suppose that’s not always possible, especially if memory gets corrupted during the update. Maybe the best defense against a bricked vehicle would be to keep a beater around that doesn’t need updates to keep running.

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An Adjustable High-Voltage Power Supply Built With Safety In Mind

January 6, 2024 by 11 Comments

It’s not entirely clear why [Advanced Tinkering] needs a 50,000-volt power supply, but given the amount of work he put into this one, we’re going to guess it will be something interesting.

The stated specs for this power supply are pretty simple: a power supply that can be adjusted between 20kV and 50kV. The unstated spec is just as important: don’t kill yourself or anyone else in the process. To that end, [Advanced] put much effort into making things as safe as possible. The basic architecture of the supply is pretty straightforward, with a ZVS driver and an AC flyback transformer. Powered by a 24-volt DC supply and an adjustable DC-DC converter, that setup alone yields something around 20kV — not too shabby, but still far short of the spec. The final push to the final voltage is thanks to a three-stage Cockcroft-Walton multiplier made with satisfyingly chunky capacitors and diodes. To ensure everything stays safe in the high-voltage stage, he took the precaution of potting everything in epoxy. Good thing, too; tests before potting showed arcing in the CW multiplier despite large isolation slots in the PCB.

Aside from the potting, some really interesting details went into this build, especially on the high-voltage side. The 3D-printed and epoxy-filled HV connector is pretty cool, as is the special wire needed to keep arcs at bay. The whole build is nicely detailed, too, with care taken to bond each panel of the rack-mount case to a common ground point.

It’s a nice build, and we can’t wait to see what [Advanced Tinkering] does with it. In the meantime, if you want to get up to speed on handling high voltage safely, check out our HV primer.

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Seeing Fireworks In A Different Light

January 6, 2024 by 5 Comments

If you’re worried that [Roman Dvořák]’s spectroscopic analysis of fireworks is going to ruin New Year’s Eve or the Fourth of July, relax — the science of this build only adds to the fun.

Not that there’s nothing to worry about with fireworks, of course; there are plenty of nasty chemicals in there, and we can say from first-hand experience that getting hit in the face and chest with shrapnel from a shell is an unpleasant experience. [Roman]’s goal with this experiment is pretty simple: to see if it’s possible to cobble together a spectrograph to identify the elements that light up the sky during a pyrotechnic display. The camera rig was mainly assembled from readily available gear, including a Chronos monochrome high-speed camera and a 500-mm telescopic lens. A 100 line/mm grating was attached between the lens and the camera, a finding scope was attached, and the whole thing went onto a sturdy tripod.

From a perch above Prague on New Year’s Eve, [Roman] collected a ton of images in RAW12 format. The files were converted to TIFFs by a Python script and converted to video by FFmpeg. Frames with good spectra were selected for analysis using a Jupyter Notebook project. Spectra were selected by moving the cursor across the image using slider controls, converting pixel positions into wavelengths.

There are some optical improvements [Roman] would like to make, especially in aiming and focusing the camera; as he says, the dynamic and unpredictable nature of fireworks makes them difficult to photograph. As for identifying elements in the spectra, that’s on the to-do list until he can find a library of spectra to use. Or, there’s always DIY Raman spectroscopy. Continue reading “Seeing Fireworks In A Different Light” →

Hackaday Podcast Episode 251: Pluto, Pinball, Speedy Surgery, And DIY GPS

January 5, 2024 by 7 Comments

Welcome to 2024! This time around, Elliot and Dan ring in a new year of awesome hacks with quite an eclectic mix. We kick things off with a Pluto pity party and find out why the tiny ex-planet deserved what it got. What do you do if you need to rename a bunch of image files? You rope a local large-language model in for the job, of course. We’ll take a look at how pinball machines did their thing before computers came along, take a fractal dive into video feedback, and localize fireworks with a fleet of Raspberry Pi listening stations. Ever wonder what makes a GPS receiver tick? The best way to find out might be to build one from scratch. Looking for some adventure? A ride on an electroluminescent surfboard might do, or perhaps a DIY “Vomit Comet” trip would be more your style. And make sure you stick around for our discussion on attempts to optimize surgery efficiency, and our look back at 2023’s top trends in the hardware world.

 

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DIY Chemistry Points The Way To Open Source Blood Glucose Testing

January 4, 2024 by 16 Comments

Every diabetic knows that one of the major burdens of the disease is managing supplies. From insulin to alcohol wipes, diabetes is a resource-intensive disease, and running out of anything has the potential for disaster. This is especially true for glucose test trips, the little electrochemical dongles that plug into a meter and read the amount of glucose in a single drop of blood.

As you might expect, glucose test strips are highly proprietary, tightly regulated, and very expensive. But the chemistry that makes them work is pretty simple, which led [Markus Bindhammer] to these experiments with open source glucose testing. It’s all part of a larger effort at developing an open Arduino glucometer, a project that has been going on since 2016 but stalled in part thanks to supply chain difficulties on the chemistry side, mainly in procuring glucose oxidase, an enzyme that oxidizes glucose. The reaction creates hydrogen peroxide, which can be measured to determine the amount of glucose present.

With glucose oxidase once again readily available — from bakery and wine-making suppliers — [Markus] started playing with the chemistry. The first reaction in the video below demonstrates how iodine and starch can be used as a reagent to detect peroxide. A tiny drop of glucose solution turns the iodine-starch suspension a deep blue color in the presence of glucose oxidase.

While lovely, colorimetric reactions such as these aren’t optimal for analyzing blood, so reaction number two uses electrochemistry to detect glucose. Platinum electrodes are bathed in a solution of glucose oxidase and connected to a multimeter. When glucose is added to the solution, the peroxide produced lowers the resistance across the electrodes. This is essentially what’s going on in commercial glucose test strips, as well as in continuous glucose monitors.

Hats off to [Markus] for working so diligently on this project. We’re keenly interested in this project, and we’ll be following developments closely. Continue reading “DIY Chemistry Points The Way To Open Source Blood Glucose Testing” →