Researchers Find “Inert” Components In Batteries Lead To Cell Self-Discharge

February 6, 2023 by Donald Papp 11 Comments

When it comes to portable power, lithium-ion batteries are where it’s at. Unsurprisingly, there’s a lot of work being done to better understand how to maximize battery life and usable capacity.

Red electrolytic solution, which should normally be clear.

While engaged in such work, [Dr. Michael Metzger] and his colleagues at Dalhousie University opened up a number of lithium-ion cells that had been subjected to a variety of temperatures and found something surprising: the electrolytic solution within was a bright red when it was expected to be clear.

It turns out that PET — commonly used as an inert polymer in cell assembly — releases a molecule that leads to self-discharge of the cells when it breaks down, and this molecule was responsible for the color change. The molecule is called a redox shuttle, because it travels back and forth between the cathode and the anode. This is how an electrochemical cell works, but the problem is this happens all the time, even when the battery isn’t connected to anything, causing self-discharge.

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Old Ham Wisdom Leads To Better Aluminum Painting

January 24, 2023 by Al Williams 50 Comments

When [bdk6] tried painting aluminum for electronic projects, he found it didn’t tend to stay painted. It would easily scratch off or, eventually, even flake off. The problem is the paint doesn’t want to adhere to the aluminum oxide coating around the metal. Research ensued, and he found an article in an old ham radio magazine about a technique that he could adapt to get good results painting aluminum.

Actually, paint apparently adheres poorly, even to non-oxidized aluminum. So the plan is to clean and remove as much aluminum oxide as possible. Then the process will convert the aluminum surface to something the paint sticks to better. Of course, you also need the right kind of paint.

The key ingredients are phosphoric acid and zinc phosphate. Phosphoric acid is found in soft drinks, but is also sold as a concrete and metal prep for painting. The zinc phosphate is part of a special paint known as a self-etching primer.

Cleaning takes soap, elbow grease, and sandpaper. The next step is a long soak in the phosphoric acid. Then you apply a few coats of self-etching primer and sand. Once it is all set, you can paint with your normal paint. That’s usually epoxy-based paint for [bdk6].

Of course, you can also dye aluminum while anodizing it. Soldering aluminum also has its challenges.

Making The One Ring By Electroplating Gold On A 3D Print

January 12, 2023 by Lewin Day 11 Comments

Electroplating is a great way to add strength or shine to a 3D print. However, we don’t see too many people trying it with gold. [HEN3DRIK] isn’t afraid to experiment, though, and pulled off some amazing, high-quality jewelry-grade plating!

The design for the project was the so-called Ring of Power from Lord of the Rings. The print was created on a resin printer at a high quality level, washed thoroughly to remove any remaining resin, and then cured. The print was then post-processed with sandpaper to make it as smooth as possible. Conductive paint was then applied, ready to take on the plating layers. [HEN3DRIK] first started by plating copper to build up a tough base layer, then nickel to prevent mixing between the copper and gold. The gold is then finally plated on top. Plating the copper is done with the ring constantly rotating to get as even a coat as possible. In contrast, the gold plating is done with a brush to avoid wasting the highly-expensive plating solution.

The final result is a gleaming gold ring that probably feels strangely light in the hand. The technique is time consuming, thanks to the need to plate multiple layers, but the results are to die for. We’ve seen [HEN3DRIK]’s fine work before, too. Video after the break.

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Wipe On, Wipe Off: Make Your Own Rain Repellent

January 9, 2023 by Kristina Panos 55 Comments

Once upon a time, we drove an old six-volt VW Beetle. One sad day, the wiper motor went out, and as this happened before the Internet heyday, there were no readily-available parts around that we were aware of. After briefly considering rubbing a potato on the windshield as prescribed by the old wives’ tale, we were quite grateful for the invention of Rain-X — a water-repelling chemical treatment for car windshields.

Boy would we have loved to know how to make it ourselves from readily-available chemicals. As you’ll see in the video below, it doesn’t take much more than dimethicone, sulfuric acid, and a cocktail of alcohols. [Terry] starts with dimethicone, which he activates with a healthy dose of concentrated sulfuric acid, done under the safety of an exhaust hood. After about 20 minutes on the stir mix-a-lot plate, [Terry] added ethanol and isopropyl alcohols. Finally, it was off to the garage with the mixture in a spray bottle.

After meticulously cleaning the windshield, [Terry] applied the solution in small areas and rubbed it in with a towel to create a thin bond between it and the glass. This creates a perfectly normal haze, which can be removed after a bit with a clean towel.

If you just love listening to your windshield wipers, at least make them move to a beat.

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Raspberry Pi biosensor with screen-printed electrodes

Raspberry Pi And PpLOGGER Make A Low-Cost Chemiluminescence Detector

December 31, 2022 by Orlando Hoilett 11 Comments

[Laena] and her colleagues at the La Trobe Institute for Molecular Science in Melbourne, Australia used a Raspberry Pi to make a low-cost electrochemiluminescence (ECL) detector to measure inflammation markers, which could be used to detect cardiovascular disease or sepsis early enough to give doctors a better chance at saving a patient’s life.

ECL reactions emit light as a result of an electrically-activated chemical reaction, making them very useful for detecting biochemical markers in blood, saliva, or other biological samples. ECL setups are fundamentally fairly straightforward. The device includes a voltage reference generator to initiate the chemical reaction and a photomultiplier tube (PMT) to measure the emitted light. The PMT outputs a current which is then converted to a voltage using a transimpedance amplifier (TIA). That signal is then sampled by the DAQCplate expansion board and the live output can be viewed in ppLOGGER in real-time.

Using the RPi allowed the team to do some necessary, but pretty simple signal processing, like converting the TIA voltage back to a photocurrent and integrating the current to obtain the ECL intensities. They mention the added signal processing potential of the RPi was a huge advantage of their setup over similar devices, however, simple integration can be done pretty easily on most any microcontroller. Naturally, they compared their device to a standard ECL setup and found that the results were fairly comparable between the two instruments. Their custom device showed a slightly lower limit of detection than the standard setup.

Their device costs roughly $1756 USD in non-bulk quantities with the PMT being the majority of the cost ($1500). Even at almost $2000, their device provides more than $8000 in savings compared to ECL instruments on the market. Though cost is much more than just the bill of materials, we like seeing the community making efforts to democratize science, and [Laena] and her colleagues did just that. I wonder if they can help us figure out the venus fly trap while they’re at it?

Picture of NanoStat in 3D-printed enclosure with LiPo battery and US quarter for scale.

An ESP32-Based Potentiostat

December 27, 2022 by Orlando Hoilett 3 Comments

Ever wanted to make your own wireless chemical sensor? Researchers from the University of California, Irvine (UC Irvine) have got you covered with their ESP32-based potentiostat.

We’ve talked about potentiostats here on Hackaday before. Potentiostats are instruments that analyze the electrical properties of an electroactive chemical cell. Think oxidation and reduction reactions (redox) from your chemistry course, if you can remember that far back. Potentiostats can be used in several different modes/configurations, but the general idea is for these instruments to induce redox reactions within a given electroactive chemical cell and then measure the resulting current produced by the reaction. By measuring the current, researchers can determine the concentration of a known substance within a sample or even determine the identity of an unknown substance, to name a few potential applications.

These instruments have become mainstays in research labs around the world and have incredible utility in the consumer space. Glucometers, devices used to measure blood glucose levels, are an example of technologies that have made their way into everyday life due to the advances made in electrochemistry and potentiostat research over the last few decades. Given their incredible utility to scientific research and medical technologies, a great deal of effort has gone into democratizing potentiostats, making them more available to the general public for educational and hobbyist purposes. Of course, any medical applications must go through rigorous testing and approvals by each country’s appropriate governing bodies. So we’re talking more non-medical purposes here.

The first popular open-source, DIY potentiostat was the CheapStat, which we’ve covered here on Hackaday before. Since then, developing newer and more advanced open-source potentiostats has become a popular endeavor within the scientific community. The researchers from UC Irvine wanted to put their own special spin on the open-source potentiostat craze and they did so with their inclusion of the ESP32 as their main processor. This obviously opens up them up do a whole host (see what we did there) of wireless capabilities that others before them have not explored.

With the ESP32, they developed a nice web-based GUI that makes controlling and collecting data from the potentiostat very seamless and user-friendly. You can imagine the great possibilities here. Teacher-led classroom demonstrations where the instructor can easily access each student’s device over the cloud to help troubleshoot or explain results. Developing soil monitoring sensors that can be deployed all around a farm to remotely collect data on feed, soil composition, and plant health. The possibilities here sure are promising.

We hope you’ll dive into their paper as it’s well worth a read. Happy hacking, Hackaday.

Homebrew 3D Printer Goop Promises Better Bed Adhesion

December 6, 2022 by Al Williams 43 Comments

Back when 3D printers were pretty new, most of us had glass beds with or without painter’s tape. To make plastic stick, you’d either use a glue stick or hair spray. Many people have moved on to various other build surfaces that don’t require help, but some people still use something to make the bed sticky and there are quite a few products on the market that claim to be better than normal glue or hairspray. [Jonas] wanted to try it, but instead of buying a commercial product, he found a recipe online for “3D printer goop” and made it himself.

You need four ingredients: distilled water and isopropyl alcohol are easy to find. The other two chemicals: PVP and PVA powder, are not too hard to source and aren’t terribly dangerous to handle. The recipe was actually from [MakerBogans] who documents this recipe as “Super Goop” and has another formula for “Normal Goop.” You’ll probably have to buy the chemicals in huge quantities compared to the tiny amounts you really need.

We assume the shots of the 3D printer printing its first layer is showing how effective the glue is. This looks like a very simple thing to mix up and keep in a sprayer. If you have some friends, you could probably do a group buy of the chemicals and it would cost nearly nothing for the small amounts of chemicals you need.

If you don’t want to order exotic chemicals, you might not need them. We used to make “goop” by dissolving ABS in acetone, but hairspray usually did the trick.

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