Sniffing pH Sensor RF Signals for Feedback Re: Your Esophagus

For about a week [Justin] had a wireless acidity level sensor in his esophagus and a pager-looking RF receiver in his pocket. So he naturally decided to use an RTL-SDR dongle to sniff the signals coming out of him. As most of our Hackaday readers know, these cheap RTL2382U-based DVB-T receivers are very handy when it comes to listening to anything between 50MHz and 1800MHz. [Justin] actually did a great job at listing all the things these receivers can be used for (aircraft traffic monitoring, weather images download, electric meter reading, pacemaker monitoring…).

After some Googling he managed to find his Bravo pH sensor user’s guide and therefore discovered its main frequency and modulation scheme (433.92MHz / ASK). [Justin] then used gqrx and Audacity to manually decode the packets before writing a browser-based tool which uses an audio file. Finally, a few additional hours of thinking allowed him to extract his dear esophagus’ pH value.

MRRF: 3D Bioprinting


There were a few keynotes at this year’s Midwest RepRap festival, and somewhat surprisingly most of the talks weren’t given by the people responsible for designing your favorite printer. One of the most interesting talks was given by [Jordan Miller], [Andy Ta], and [Steve Kelly] about the use of RepRap and other 3D printing technologies in biotechnology and tissue engineering. Yep, in 50 years when you need a vital organ printed, this is where it’ll come from.

[Jordan] got his start with tissue engineering and 3D printing with his work in printing three-dimensional sugar lattices that could be embedded in a culture medium and then dissolved. The holes left over from the sugar became the vasculature and capillaries that feed a cell culture. The astonishing success of his project and the maker culture prompted him and others to start the Advanced Manufacturing Research Institute to bring young makers into the scientific community. It’s a program hosted by Rice University and has seen an amazing amount of success in both research and getting makers into scientific pursuits.

One of these young makers is [Andy Ta]. An economics major, [Andy] first heard of the maker and RepRap community a few years ago and bought a MakerBot Cupcake. This was a terrible printer, but it did get him involved in the community, hosting build workshops, and looking into 3D printing build around DLP-cured UV resin. At AMRI, [Andy] started looking at the properties of UV-cured resin, figuring out the right type of light, resin, and exposure to create a cured resin with the right properties for printing cell colonies. You can check out [Andy]‘s latest work on his webzone.

[Steve Kelly] has also done some work at AMRI, but instead of the usual RepRap or DLP projector-based printers, he did work with shooting cell cultures out of an ink jet print head. His initial experiments involved simply refilling an ink jet cartridge with a bacterial colony and discovering the cells actually survived the process of being heated and shot out of a nozzle at high speed. Most ink jets printers don’t actually lay out different colors on a precise grid, making it unusable for growing cell cultures. [Steve] solved this problem with an inkjet controller shield attached to a RepRap. All of [Steve]‘s work is documented on his Github.

It’s all awesome work, and the beginnings of both bioengineering based on 3D printers, and an amazing example of what amateur scientists and professional makers can do when they put their heads together. Video link below.

[Read more...]

Taste-O-Vision Is Now A Thing


Not satisfied with late 1950s concepts of Smell-O-Vision [Nimesha]  has created something extraordinary: A digital taste sensor, capable of representing taste with a little bit of heat, electricity, and an Arduino

The device purportedly works by via thermal and electrical stimulation of the tongue using silver electrodes. According to this video, different tastes are created with different currents and temperatures. For example, a sour taste is produced on the electrodes by varying the current from 60uA to 180uA and increasing the temperature up to 30 degrees C. Mint is produced by simply decreasing the temperature from 22C to 19C.

The control electronics include an Arduino, a motor controller, and a heat sink attached to one of the silver electrodes. Communication is done through USB, and of course there’s a mobile app for it, more specifically a protocol called Taste Over IP. This allows anyone to send a taste to anyone with one of these devices.

Videos below, and before you laugh, we’d really like to try one of these out.

Thanks [Jess] for the tip.

[Read more...]

Improving A Homebrew CT Scanner With Barium


[Peter] has been working on his homebrew CT scanner for a while, and it’s finally become something more than a spinning torus of plywood. He’s managed to image the inside of a few pieces of produce using an off-the-shelf radiation detector and a radioactive barium source

When we last saw [Peter]‘s CT scanner, he had finished the mechanical and electronic part of the Stargate-like device, but the radioactive source was still out of reach. He had initially planned on using either cadmium 109 or barium 133. Both of these presented a few problems for the CT scanner.

The sensor [Peter] is a silicon photodiode high energy particle detector from Radiation Watch this detector was calibrated for cesium with a detection threshold of around 80keV. This just wasn’t sensitive enough to detect 22keV emissions from Cd109, but a small add-on board to the sensor can recalibrate the threshold of the sensor down to the noise floor.

Still, cadmium 109 just wasn’t giving [Peter] the results he wanted, resulting in a switch to barium 133. This was a much hotter source (but still negligible in the grand scheme of radioactivity) that allowed for a much better signal to noise ratio and shorter scans.

With a good source, [Peter] started to acquire some data on the internals of some fruit around his house. It’s still a slow process with very low resolution – the avocado in the pic above has 5mm resolution with an acquisition time of over an hour – but the whole thing works, imaging the internal structure of a bell pepper surprisingly well.

MobilECG goes open source


After a failed crowdfunding campaign, MobilECG has gone open source. MobilECG is a medical grade 12 lead electrocardiograph. A 12 lead system is quite a bit more complex than some of the ECG systems we have featured in the past.  [Péter], the founder and designer of the device attempted to fund it through an Indiegogo campaign. While MobilECG is relatively cheap, medical certifications are not. The campaign didn’t reach its goal of $230,000 USD. [Péter] tried again with a grass-roots donation round at his website. That round also fell short of [Péter's] goal to keep working on the project. Rather than let his hard work go to waste, [Péter] has made the decision to release his hardware and software to the community. The hardware is licensed under CERN OHL v1.2. The software is released under the humorously named WTFPL.

While we’re not ECG experts, the basic hardware design appears to be sound. MobileECG is based around the Texas Instruments ADS1278 octal analog to digital converter. Two AVR microcontrollers are used, an ATTiny24, and an ATUC64. The analog design incorporates such niceties as lead off detection and defibrillator protection. It should be noted that there are some known bugs in the design, [Péter] mentions he can be contacted with questions. The software seems to be in an early state, and would require quite a bit of work to get it to a final design. While we do wish [Péter] had better luck with his campaign, we’re always glad to see designs released into the open source community.

[Read more...]

A Digital Condom a Reality Thanks to Arduino


[Bill Gates]‘ foundation is currently offering up a ton of prizes for anyone who can improve the condom. It’s a laudable goal, and somewhat difficult; one of the main reasons why male condoms aren’t used as often as they should is the,  “male perspective… that condoms decrease pleasure as compared to no condom.”

While most of the work inspired by the [Gates] foundation is work investigating a change in the geometry of the condom, [Firaz Peer] and [Andrew Quitmeyer] of Georgia Tech managed to solve this problem with an Arduino.

The basic idea of the Electric Eel – yes, that’s the name – is to deliver short electric impulses, “along the underside of the shaft for increased stimulation”. These impulses are delivered in response to different sensor inputs – in the video example (surprisingly safe for work) they’re using a force resistor wrapped around the chest for an electrical stimulation with every breath.

Although this is only a prototype, the hope is the conductors in the condom can eventually be implanted along the inside surface of a condom during manufacturing.

Video after the break.

[Read more...]

A Simple Posture Sensor


If you are on the computer for a large part of the day, posture becomes a serious issue that can negatively impact your health. [Wingman] saw this problem, and created a hack to help solve it. His simple posture sensor will monitor the position of your head relative to the chair, and reminds you to sit up straight.

The posture sensor is built around the HC-SR04 ultrasonic distance sensor, an Attiny85, and a piezo speaker. We’ve seen this distance sensor used in the past for a few projects. Rather than going down the wearable route, which has its own drawbacks, [Wingman] decided to attach his sensor on the back of his chair. The best part is that the sensor is not mounted directly on the chair, but rather on a piece of fabric allowing it to be easily moved when needed.

Given how low-cost and small the sensor is, the project can be easily expanded by adding multiple sensors in different locations. This would allow the angle of the back and possibly the neck to be determined, giving a more accurate indicator of poor posture. There are very few hacks out there that address bad posture. Do you have a project that helps address bad posture? Have you used video processing or a wearable device to monitor your posture? Let us know in the comments an don’t forget to send post links about them to our tips line.