Arduino Radar Watches You Breathe

We’ve all likely watched an episode of “Star Trek” and admired the level of integration on the sick bay diagnostic bed. With its suite of wireless sensors and flat panel display, even the 1960s imagining of the future blows away the decidedly wired experience of a modern-day ICU stay. But we may be getting closer to [Dr. McCoy]’s experience with this radar-based respiration detector.

[Øyvind]’s build, which takes the origin of the term “breadboard” to heart, is based on a not-inexpensive Xethru module, which appears to be purpose-built for detecting respiration. The extra-thick PC board seems to house the waveguides internally, which is a neat trick but might limit how the module can be deployed. The module requires both a USB interface and level shifter to interface the 2.8V levels of the module to the 5V Arduino Uno. In the video below, [Øyvind]’s prototype simply lights an RGB LED in response to the chest movement it detects, but there’s plenty of potential for development here. We’ve seen a laser-based baby breathing monitor before; perhaps this systems could be used to the same end without the risk of blinding your tyke. Or perhaps better diagnostics for sleep apnea patients than an intrusive night in a sleep study lab.

Clocking in at $249 for the sensor board and USB interface, this build is not exactly for the faint of heart or the light of wallet. But as an off-the-shelf solution to a specific need that also has a fair bit of hacking potential, it may be just the thing for someone. Of course if radar is your thing, you might rather go big and build something that can see through walls.

Continue reading “Arduino Radar Watches You Breathe”

How Many Puffs Does It Take To Kill An E-Cigarette?

Most of us have probably heard the old Tootsie Pop slogan, “How many licks does it take to get to the center of a Tootsie Pop?” [E-Smoker2014] had a similar question about his e-cigarettes. These devices are sometimes advertised with the number of puffs they are good for. [E-Smoker2014] had purchased an e-cigarette on a trip to Belgium that advertised 500 puffs. After a bit of use, he started to suspect that he wasn’t getting the advertised number of puffs in before the battery would die. Rather than just accept that the world may never know for sure, he decided to test it out himself.

There aren’t many details on this build, but you can tell what’s going on from the video below. [E-Smoke2014r] built a machine to artificially puff on an e-cigarette. The e-cigarette is hooked up to what appears to be vinyl tubing. This tubing then attaches to a T-splitter. One end of the splitter is hooked up to a DIY actuator valve that can open or close the port. The other end of the splitter is hooked up to more tubing, which in turn is attached to a plastic cylinder placed in a container of water.

To simulate breathing, the computer first opens the relief valve in the splitter. It then mechanically lowers the plastic container into the bowl of water, pushing out a bunch of air in the process. The valve closes, and the computer then raises the plastic container out of the water. This action creates suction that draws air in through the e-cigarette like a normal user would do with their lungs. The computer increases the puff count and then repeats the process, expelling any vapor out of the relief valve.

The results of the test indicated that [E-Smoker] could only get 59 puffs out of this particular e-cigarette before draining the battery. Not even close to the advertised 500 puffs. Maybe he should consider building his own e-cigarette vaporizer? Continue reading “How Many Puffs Does It Take To Kill An E-Cigarette?”