Hacking A Reader For Medical Test Strips


[Rahul] works at a startup that produces cutting edge diagnostic test cards. These simple cards can test for enzymes, antibodies, and diseases quickly and easily. For one test, this greatly speeds up the process of testing and diagnosis, but since these tests can now be administered en masse, health services the world over now have the problem of reading, categorizing, and logging thousands of these diagnostic test cards.

The normal solution to this problem is a dedicated card scanner, but these cost tens of thousands of dollars. At a 24-hour hackathon, [Rahul] decided to bring down the cost of the card scanners by whipping up his own, built from a CD drive and an Arduino.

The card [Rahul] used, an A1c card that tests for glucose bound to hemoglobin, has a few lines on the card that fluoresce with different intensify depending on the test results. This can be easily read with a photodiode connected to an Arduino. The mechanical part of the build consisted of an old CD drive with a 3D printed test strip adapter. Operation is very simple – just put the test strip in the test strip holder, press a button, and the results of the test are transmitted over Bluetooth.

Not only is [Rahul]’s build extremely simple, it’s also extremely useful and was enough to net him the ‘Most Innovative Project’ prize at the hackathon in his native Singapore.

Pulse oximeter displays blood oxygen levels on a PC

The last time you were in the emergency room after a horrible accident involving a PVC pressure vessel, a nurse probably clipped a device called a pulse oximeter onto one of your remaining fingers. These small electronic devices detect both your pulse and blood oxygen level with a pair of LEDs and a photosensor. [Anders] sent in a great tutorial for building your own pulse oximeter using a fancy ARM dev board, but the theory behind the operation of this device can be transferred to just about any microcontroller platform.

The theory behind a pulse oximeter relies on the fact that hemoglobin absorbs red and infrared light differently based on its oxygenation levels. By shining a red and IR LED through a finger onto a photoresistor, it’s possible to determine a person’s blood oxygen level with just a tiny bit of math.

Of course a little bit of hardware needs to be thrown into the project; for this, [Anders] used an EMF32 Gecko starter kit, a great looking ARM dev board. After connecting the LEDs to a few transistors and opamps, [Anders] connected his sensor circuit to the ADC on the Gecko board. From here it was very easy to calculate his blood oxygen level and even display his pulse rate to a PC application.

Yes, for just the price of a dev board and a few LEDs, it’s possible to build your own medical device at a price far below what a commercial pulseox meter would cost. FDA approval not included.

Robo Doc reads children’s pulses without scaring them

[Markus] recently took his 14-month-old daughter to the pediatrician for a routine checkup. During the examination, the doctor needed to measure her pulse and quickly clamped an infrared heart rate monitor onto her finger. Between the strange device clamped to her finger and incessant beeping of machines, [Markus]’ daughter got scared and started to cry. [Markus] thought these medical devices were far too scary for an infant, so he designed a funny robot to read an infant’s heart rate.

[Markus] liked the idea the Tengu, a robot with a LED matrix for facial expressions, and used it as inspiration for the interface and personality of his RoboDoc. To read a child’s pulse rate, [Markus] used a photoplethysmography sensor; basically an IR LED and receiver that reflects light off a finger bone and records the number of heartbeats per minute.

The build is tied together with a speaker allowing the RoboDoc to give the patient instructions, and a servo to turn the head towards the real, human doctor and display the recorded heart rate.

We think the RoboDoc would be far less disconcerting for an infant that a huge assortment of beeping medical devices, and we can’t wait to see [Markus]’ next version of non-scary doctor’s tools.

ReactionWare 3D printed medicine

The University of Glasgow has released a Chemistry research paper covering the applicational process of printing pharmaceutical compounds.

Yes thats correct actually printing medication. Using various feedstock of chemicals they see a future where manufacturing your medication from home will be possible. Using standard 3D printing technology it is possible to assemble pre-filled “vessels” in such a way that the required chemical reactions take place to produce the required medication. This will be like having a minature medication manufacturing facility in your home. The possible implications of this could be far reaching.

There would need to be a locked down software etc or certain chemcials restrictions to prevent the misuse of this technology. Prof [Lee Cronin], who came up with the paper’s principal has called this process “reactionware”

Professor [Cronin] found, using this fabrication process, that even the most complicated of vessels could be built relatively quickly in just a few hours.

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Printing organs with a 3D printer

[Jordan Miller], [Christopher Chen], and a whole bunch of other researchers at the department of bioengineering at U Penn have figured out a way to print 3D tissues using a 3D printer. In this case, a RepRap modified to print sugar.

Traditional means of constructing living 3D tissues face a problem – in a living body, there’s a whole bunch of vasculature sending Oxygen and nutrients to the interior cells. In vitro, these nutrients can’t get to the cells in the core of a mass of tissue. [Jordan], [Chris], et al. solved this problem by printing a three-dimensional sugar lattice. After encasing this lattice in a gel embedded with living cells, the sugar can be dissolved and the nutrients pumped through the now hollow capillaries in the gel.

If you have access to Nature, the full text article is available here. There’s also a great video showing off this technique after the break.

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Tearing down a colonoscopy pill camera

Normally, colonoscopies are rather invasive affairs. Swallowing a small pill with a camera is much more amenable to a patient’s dignity and are seeing increasing usage in colon cancer screening. [Mike] acquired a pillcam from a relative who underwent the procedure and did a teardown to figure out how it works.

To get the video signal out of the body, the pillcam has two contacts that conduct the video signal through the body to stick-on contacts; It’s a more power efficient way of doing things versus a radio transmitter. After opening the plastic and metal capsule, [Mike] found three batteries and an impressively small circuit that contained an array of LEDs, a camera, and what might be a small MCU.

Taking a scope to the electronics in the pill, [Mike] found an impressively complex waveform that sends uncompressed image data to the receiver every few seconds. Although the camera was somewhat destroyed in the teardown, we’re pretty confident [Mike] could decode the image data if he had another… ‘sample.’

[Mike] says if you can ‘retrieve’ another one of these pill cameras, he’ll gladly accept any donations and look into the differences between different makes and models. Just make sure you sanitize it first. After the break you can see [Mike]’s teardown and the inevitable poop jokes in the comments. One last thing – if you’re over 50, doctors should be looking at your colon every 5 or 10 years. Get screened.

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Building an artificial heart with ferrofluids

Here’s something we thought we’d never see on Hackaday. [Chris Suprock] is developing an artificial heart he calls Steel Heart. It’s an artificial heart powered by electromagnets and ferrofluids.

The idea behind [Chris]’ artificial heart is ingenious in its simplicity. An elastic membrane is stretched across a frame and a magnetic liquid (or ferrofluid, if you prefer) is poured across the membrane. An electromagnet is activated and the membrane stretches out, simulating the beating of a heart. Put a few of these together and you’ve got a compact, biologically inert pump that’s perfect for replacing an aging ticker.

[Chris]’ plan to use ferrofluids and electromagnets as an artificial heart give us pause to actually think about what he’s done here. Previously, artificial hearts used either pneumatics or motors to pump blood throughout the body. Pneumatic pumps required plastic tubes coming out of the body – not a satisfactory long-term solution. Motor-driven pumps can rupture red blood cells leading to hemolysis. Using ferrofluids and an elastic membrane allows for the best of both worlds – undamaged blood cells and transdermal induction charging.

Not only is [Chris] designing a freaking artificial heart, he also came up with a useful application of ferrofluids. We were nearly ready to write off magnetic particles suspended in a liquid as a cool science toy or artistic inspiration. You can check out [Chris]’ indiegogo video with a demo of the ferrofluid pump in action after the break.

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