Unless you’ve been living under a high voltage transformer, you’ve heard about the potential for Samsung’s latest phone, the Note7, to turn into a little pocket grenade without warning. With over 2.5 million devices in existence, it’s creating quite a headache for the company and its consumers.
They quickly tied the problem to faulty Li-ion batteries and started replacing them, while issuing a firmware update to stop charging at 60 percent capacity. But after 5 of the replacement phones caught fire, Samsung killed the Note7 completely. There is now a Total Recall on all Note7 phones and they are no longer for sale. If you have one, you are to turn it off immediately. And don’t even think about strapping it into a VR headset — Oculus no longer supports it. If needed, Samsung will even send you a fireproof box and safety gloves to return it.
It should be noted that the problem only affects 0.01% of the phones out there, so they’re not exactly going to set the world on fire. However, it has generated yet another discussion about the safety of Li-ion battery technology.
It was just a few months ago we all heard about those hoverboards that would catch fire. Those questionably-engineered (and poorly-named) toys used Li-ion batteries as well, and they were the source of the fire problem. In the wake of this you would think all companies manufacturing products with Li-ion batteries in them would be extra careful. And Samsung is no upstart in the electronics industry — this should be a solved problem for them.
Why has this happened? What is the deal with Li-ion batteries? Join me after the break to answer these questions.
Every now and then you need to make your own capacitor. That includes choosing a dielectric for it, the insulating material that goes between the plates. One dielectric material that I use a lot is paraffin wax which can be found in art stores and is normally used for making candles. Another is resin, the easiest to find being automotive resin used for automotive body repairs.
The problem is that you sometimes need to do the calculations for the capacitor dimensions ahead of time, rather than just throwing something together. And that means you need to know the dielectric constant of the dielectric material. That’s something that the manufacturer of the paraffin wax that makes it for art stores won’t know, nor will the manufacturers of automotive body repair resin. The intended customers just don’t care.
It’s therefore left up to you to measure the dielectric constant yourself, and here I’ll talk about the method I use for doing that.
It seems like every other day we hear about some hacker, tinkerer, maker, coder or one of the many other Do-It-Yourself engineer types getting their hands into a complex field once reserved to only a select few. Costs have come down, enabling common everyday folks to equip themselves with 3D printers, laser cutters, CNC mills and a host of other once very expensive pieces of equipment. Getting PCB boards made is literally dirt cheap, and there are more inexpensive Linux single board computers than we can keep track of these days. Combining the lowering hardware costs with the ever increasing wealth of knowledge available on the internet creates a perfect environment for DIYers to push into ever more specific scientific fields.
One of these fields is biomedical research. In labs across the world, you’ll find a host of different machines used to study and create biological and chemical compounds. These machines include DNA and protein synthesizers, mass spectrometers, UV spectrometers, lyophilizers, liquid chromatography machines, fraction collectors… I could go on and on.
These machines are prohibitively expensive to the DIYer. But they don’t have to be. We have the ability to make these machines in our garages if we wanted to. So why aren’t we? One of the reasons we see very few biomedical hacks is because the chemistry knowledge needed to make and operate these machines is generally not in the typical DIYers toolbox. This is something that we believe needs to change, and we start today.
In this article, we’re going to go over how to convert basic chemical formulas, such as C9H804 (aspirin), into its molecular structure, and visa versa. Such knowledge might be elementary, but it is a requirement for anyone who wishes to get started in biomedical hacking, and a great starting point for the curious among us.
We can only assume he has a thing for copper as an element. After growing his copper crystal it wasn’t long before he followed a winding road of copper based experiments and found himself with a supply of copper (II) oxide after rendering it from common household chemicals. He had two missions for it. The first was to witness an unfettered copper oxide based thermite reaction. Some had assured him it was practically explosive. The other was to attempt refining pure copper using the reaction. That would be pretty cool considering it all started out as an impure blend of laundry detergents and fertilizer.
Can you make a spectrometer for your home lab all from materials you have sitting around? We might not believe it from a less credible source, but this MIT course does indeed build a spectrometer from foam board using two razor blades as the silt cover and a writable CD as the diffraction grating. The coolest part is removing the metal backing of the CD.
Hackaday reader [gratian] tipped us off about the course available from MIT courseware called Nanomaker. It boils down some fairly complicated experiments to the kind one can do in the home lab without involving thousands of dollars of lab equipment. The whole point is to demystify what we think of as complicated devices and topics surrounding photovoltaics, organic photovoltaics, piezoelectricity and thermoelectricity.
Spectrometers are used to analyze the wavelengths of a light source. Now that you have a measurement tool in hand it’s time to build and experiment with some light sources of your own. Here you can see an LED that is the topic of one of the course labs.
If you have a bit of background in chemistry this is a good step-by-step guide for getting into these types of experiments at home. It reminds us of some of the really cool stuff [Jeri Ellsworth] was doing in her garage lab, like making her own EL panels.
[Nurdrage] puts out a lot of neat videos, mostly about home chemistry. For the home chemist it is occasionally desirable to pull a vacuum. For example, a potentially dangerous chemical can be boiled and distilled at a much lower temperature than at atmospheric pressures.
However, there’s a problem with just going to the local import store and buying the first vacuum pump on the shelf. They are primarily designed for atmospheric gasses and tend to melt when exposed to solvents. If you’re a big university or a commercial lab this is no problem. You just drop three grand on a Teflon diaphragm pump or a liquid nitrogen trap. For the home chemist who’s already having enough trouble just buying the chemicals needed for neat experiments, this is not an option.
[Nurdrage] demonstrates the proper usage of a much cheaper option: an aspirator vacuum pump. You might remember something similar from high school chemistry. School pumps generally use flowing tap water to produce the vacuum. [Nurdrage] is saving water by using a fluid pump and a reservoir to drive his aspirator.
Aspirator pumps use the Venturi effect to create a vacuum. These devices are cheap because there are no moving parts. We looked it up and the one he is using costs ten US dollars on fleabay. It can pull enough vacuum to boil water below room temperature.
The video is really good and provides a lot of useful information. It also seems like a really useful device for other hacking tasks outside of home chemistry. Video after the break.
Film photography began with a mercury-silver amalgam, and ended with strips of nitrocellulose, silver iodide, and dyes. Along the way, there were some very odd chemistries going on in the world of photography, from ferric and silver salts to the prussian blue found in Cyanotypes and blueprints.
Cyanotypes are made by applying potassium ferricyanide and ferric ammonium citrate to some sort of medium, usually paper or cloth. This is then exposed via UV light (i.e. the sun), and whatever isn’t exposed is washed off. Instead of the sun, [David] is using a common UV laser diode to expose his photographs. he already has the mechanics of this printer designed, and he should be able to reach his goal of 750 dpi resolution and 8-bit monochrome.
Digital photography will never go away, but there will always be a few people experimenting with light sensitive chemicals. We haven’t seen many people experiment with these strange alternative photographic processes, and anything that gets these really cool prints out into the world is great news for us.