Digital Dining With Charged Chopsticks

You step out of the audience onto a stage, and a hypnotist hands you a potato chip. The chip is salty and crunchy and you are convinced the chip is genuine. Now, replace the ordinary potato chip with a low-sodium version and replace the hypnotist with an Arduino. [Nimesha Ranasinghe] at the University of Maine’s Multisensory Interactive Media Lab wants to trick people into eating food with less salt by telling our tongues that we taste more salt than the recipe calls for with the help of electrical pulses controlled by everyone’s (least) favorite microcontroller.

Eating Cheetos with chopsticks is a famous lifehack but eating unsalted popcorn could join the list if these chopsticks take hold and people want to reduce their blood pressure. Salt is a flavor enhancer, so in a way, this approach can supplement any savory dish.

Smelling is another popular machine hack in the kitchen, and naturally, touch is popular beyond phone screens. You have probably heard some good audio hacks here, and we are always seeing fascination stuff with video.

The Ins and Outs of Geiger Counters, for Personal Reasons

There are times in one’s life when circumstances drive an intense interest in one specific topic, and we put our energy into devouring all the information we can on the subject. [The Current Source], aka [Derek], seems to be in such a situation these days, and his area of interest is radioactivity and its measurement. So with time to spare on his hands, he has worked up this video review of radioactivity and how Geiger counters work.

Why the interest in radioactivity? Bluntly put, because he is radioactive, at least for the next week. You see, [Derek] was recently diagnosed with thyroid cancer, and one of the post-thyroidectomy therapeutic options to scavenge up any stray thyroid cells is drinking a cocktail of iodine-131, a radioisotope that accumulates in thyroid cells and kills them. Trouble is, this leaves the patient dangerously radioactive, necessitating isolation for a week or more. To pass the time away from family and friends, [Derek] did a teardown on a commercial Geiger counter, the classic Ludlum Model 2 with a pancake probe. The internals of the meter are surprisingly simple, and each stage of the circuit is easily identified. He follows that up with a DIY Geiger counter kit build, which is also very simple — just a high-voltage section made from a 555 timer along with a microcontroller. He tests both instruments using himself as a source; we have to say it’s pretty alarming to hear how hot he still is. Check it out in the video below.

Given the circumstances, we’re amazed that [Derek] is not only keeping his cool but exhibiting a good sense of humor. We wish him well in his recovery, and if doing teardowns like this or projects like this freezer alarm or a no-IC bipolar power supply helps him cope, then we all win.

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Homebrew Pancreas Gets 30 Minutes of Fame

It is pretty unusual to be reading Bloomberg Businessweek and see an article with the main picture featuring a purple PCB (the picture above, in fact). But that’s just what we saw this morning. The story is about an open source modification to an insulin pump known as the RileyLink. This takes advantage of older Medtronic brand insulin pumps and allows you to control the BLE device from a smartphone remotely and use more sophisticated software to control blood sugar levels.

Of course, the FDA isn’t involved. If they were, the electronics would cost $7,000 instead of $250 — although, in fairness, that $250 doesn’t cover the cost of the used pump. Why it has to be a used pump is a rather interesting story. The only reason the RileyLink is possible is due to a security flaw and an active hacker community.

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Reverse Engineering a DNA Sequencer

Improvements in methodology have dramatically dropped the cost of DNA sequencing in the last decade. In 2007, it cost around $10 million dollars to sequence a single genome. Today, there are services which will do it for as little as $1,000. That’s not to bad if you just want to examine your own DNA, but prohibitively expensive if you’re looking to experiment with DNA in the home lab. You can buy your own desktop sequencer and cut out the middleman, but they cost in the neighborhood of $50,000. A bit outside of the experimenter’s budget unless you’re Tony Stark.

But thanks to the incredible work of [Alexander Sokolov], the intrepid hacker may one day be able to put a DNA sequencer in their lab for the cost of a decent oscilloscope. The breakthrough came as the result of those two classic hacker pastimes: reverse engineering and dumpster diving. He realized that the heavy lifting in a desktop genome sequencer was being done in a sensor matrix that the manufacturer considers disposable. After finding a source of trashed sensors to experiment with, he was able to figure out not only how to read them, but revitalize them so he could introduce a new sample.

To start with, [Alexander] had to figure out how these “disposable” sensors worked. He knew they were similar in principle to a digital camera’s CCD sensor; but rather than having cells which respond to light, they read changes in pH level. The chip contains 10 million of these pH cells, and each one needs to be read individually hundreds of times to capture the entire DNA sequence.

Enlisting the help of some friends who had experience reverse engineering silicon, and armed with an X-Ray machine and suitable optical microscope, he eventually figured out how the sensor matrix worked electrically. He then designed a board that reads the sensor and dumps the “picture” of the DNA sample to his computer over serial.

Once he could reliably read the sensor, the next phase of the project was finding a way to wash the old sample out so it could be reloaded. [Alexander] tried different methods, and after several wash and read cycles, he nailed down the process of rejuvenating the sensor so its performance essentially matches that of a new one. He’s currently working on the next generation of his reader hardware, and we’re very interested to see where the project goes.

This isn’t the first piece of DIY DNA hardware we’ve seen here at Hackaday, and it certainly won’t be the last. Like it or not, hackers are officially fiddling with genomes.

Shining a Light on Hearing Loss

When auditory cells are modified to receive light, do you see sound, or hear light? To some trained gerbils at University Medical Center Göttingen, Germany under the care of [Tobias Moser], the question is moot. The gerbils were instructed to move to a different part of their cage when administrators played a sound, and when cochlear lights were activated on their modified cells, the gerbils obeyed their conditioning and went where they were supposed to go.

In the linked article, there is software which allows you to simulate what it is like to hear through a cochlear implant, or you can check out the video below the break which is not related to the article. Either way, improvements to the technology are welcome, and according to [Tobias]: “Optical stimulation may be the breakthrough to increase frequency resolution, and continue improving the cochlear implant”. The first cochlear implant was installed in 1964 so it has long history and a solid future.

This is not the only method for improving cochlear implants, and some don’t require any modified cells, but [Tobias] explained his reasoning. “I essentially took the harder route with optogenetics because it has a mechanism I understand,” and if that does not sound like so many hackers who reach for the tools they are familiar with, we don’t know what does. Revel in your Arduinos, 555 timers, transistors, or optogenetically modified cells, and know that your choice of tool is as powerful as the wielder.

Optogenetics could become a hot ticket at bio maker spaces. We have talked about optogenetics in lab rodents before, but it also finds purchase in zebrafish and roundworm.

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An MRI-Safe 3D Printed Pneumatic Stepper Motor

You will no doubt have seen those videos where MRI machines suck up all sorts of metallic objects with hilariously disastrous results. The magnetic field in one of these machines can easily pull in metal objects from across the room, exerting a force of several hundred pounds on any ferrous object unlucky enough to wander too close. As you can probably imagine, designing mechanical devices that can operate in such an intense magnetic field is exceptionally difficult.

But this fully 3D printed pneumatic stepper motor designed by [Foad Sojoodi Farimani] might one day change that. The PneuAct, which he presented at the recent International Conference on Robotics and Automation (ICRA) in Brisbane, Australia, manages to run at up to 850 RPM with full position control using bursts of air rather than electronic pulses. Made entirely of plastic and without any electronic components, the PneuAct can not only operate in intense magnetic fields but also areas with flammable gases where sparks could potentially cause an explosion.

We often say that a design is “fully” 3D printable, even though it might require screws or other bits of hardware. But in the case of the PneuAct, it’s truly all printed. It has to be, or else the whole thing would be ripped apart when it got to close to the MRI machine. Each and every piece of the motor is printed in ABS, and can be used without any additional machining or cleanup. No lubrication is required, and [Foad] mentions that the whole thing is so cheap that it can be disposable. Which is a huge advantage in medical environments where contamination could be a concern.

Design-wise the PneuAct is essentially an expanded version of the 3D printed air motors we’ve seen previously, but it would be fair to say that none has ever been studied so closely before.

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Help With Stuttering Could Come From Electricity

At the University of Oxford, [Jen Chesters] conducts therapy sessions with thirty men in a randomized clinical trial to test the effects of tDCS on subjects who stutter. Men are approximately four times as likely to stutter and the sex variability of the phenomenon is not being tested. In the randomized sessions, the men and [Jen] are unaware if any current is being applied, or a decoy buzzer is used.

Transcranial Direct Current, tDCS, applies a small current to the brain with the intent of exciting or biasing the region below the electrode. A credit-card sized card is used to apply the current. Typically, tDCS ranges from nine to eighteen volts at two milliamps or less. The power passing through a person’s brain is roughly on par with the kind of laser pointer you should not point straight into your eyeball and is considered “safe,” with quotation marks.

A week after the therapy, conversational fluency and the ability to recite written passages shows improvement over the placebo group which does not show improvement. Six weeks after the therapy, there is still measurable improvement in the ability to read written passages, but sadly, conversational gains are lost.

Many people are on the fence about tDCS and we urge our citizen scientists to exercise all the caution you would expect when sending current through the brain. Or, just don’t do that.