CPAP (Continuous Positive Airway Pressure) machines can be life-changing for people with sleep apnea. [Scott Clandinin] benefits from his CPAP machine and devised a way to improve his quality of life even further with a non-destructive modification to monitor his machine’s humidifier.

With a CPAP machine, all air the wearer breathes is air that has gone through the machine. [Scott]’s CPAP machine has a small water reservoir which is heated to humidify the air before it goes to the wearer. However, depending on conditions the water reservoir may run dry during use, leading to the user waking up dried out and uncomfortable.

To solve this in a non-invasive way that required no modifications to the machine itself, [Scott] created a two-part device. The first part is a platform upon which the CPAP machine rests. A load cell interfaced to an HX711 Load Cell Amplifier allows an Arduino Nano to measure the mass of the CPAP machine plus the integrated water reservoir. By taking regular measurements, the Arduino can detect when the reservoir is about to run dry and sound an alarm. Getting one’s sleep interrupted by an alarm isn’t a pleasant way to wake up, but it’s much more pleasant than waking up dried out and uncomfortable from breathing hot, dry air for a while.

The second part of the device is a simple button interfaced to a hanger for the mask itself. While the mask is hung up, the system is idle. When the mask is removed from the hook, the system takes measurements and goes to work. This makes activation hassle-free, not to mention also avoids spurious alarms while the user removes and fills the water reservoir.

Non-invasive modifications to medical or other health-related devices is common, and a perfect example of nondestructive interfacing is the Eyedriveomatic which won the 2015 Hackaday Prize. Also, the HX711 Load Cell Amplifier has an Arduino library that was used in this bathroom scale refurb project.

When you, perhaps after being late for an important event one too many times, decide to build a wall clock, there are many DIY options from which to choose. But none may be as massive or unique as the aptly named “Titan Clock.”

To justify this particular design, hacker “ProtheanSoft” lists several of its advantages, such as its large size, energy efficiency (runs on a smartphone charger), thinness (only 18mm thick with casing), and of course, affordability.

The Titan Clock—which can be assembled for less than $50—consists of RGB LEDs, inexpensive craft materials like foamcore board, acrylic and aluminum sheets, as well as recycled components including the diffuser from a broken LCD monitor or TV to generate a uniform glow for each segment. 

ProtheanSoft’s project uses an Arduino Nano for control, along with with a DS3231 RTC module for accurate timekeeping. In this version, the Arduino is programmed to display the time and change color every hour based on a predetermined table.

Interested in creating your own? You can find more details on the build here, as well its code and a wiring diagram on GitHub.

If you’ve ever wished you could levitate tiny drops of liquid, small solids, or insects in mid-air, new research has you covered. That’s because Asier Marzo, Adrian Barnes, and Bruce W. Drinkwater have developed a 3D-printed, Arduino Nano-controlled acoustic levitator.

Their device uses two arrays of 36 sonic transducers in a concave pattern, which face each other in order to suspend objects like Styrofoam, water, coffee and paper in between. Several items can even be trapped at the same time, and liquid is inserted into the “levitation zone” via a syringe.

The principle is similar to the vibration you feel when next to a large speaker, but in this case, the homemade levitator employs ultrasonic waves to push particles without causing any damage to humans.

Acoustic levitation has been explored in hundreds of studies for applications in pharmaceuticals, biology or biomaterials. It holds the promise of supporting innovative and ground-breaking processes. However, historically levitators have been restricted to a small number of research labs because they needed to be custom-made, carefully tuned and required high-voltage. Now, not only scientists but also students can build their own levitator at home or school to experiment and try new applications of acoustic levitation.

If you’d like to make your own, be sure to check out Marzo’s Instructables post or the team’s full paper on the experiment here.

If you suppose that electromagnetically-propelled projectiles are strictly the purview of well-funded government research labs, think again! Using two sets of coils wrapped around custom 3D-printed base structures and an Arduino Nano for control, YouTuber “Gyro” created his own coilgun capable of propelling steel fast enough to dent a piece of wood.

When fired, a photodiode at the end of each electromagnet coil sends a signal to the Arduino. This, in turn, shuts off the coil, allowing it freely escape the barrel.

As noted in his Instructables write-up, the gun is constructed without large capacitors, which can be expensive and dangerous. Instead, two LiPo battery packs are combined to produce around 22 volts, though this and the number of coils used, could be increased to produce a more powerful device!

You may be familiar with “Pop-A-Shot” at arcades and amusement parks, which allows you to shoot baskets at a hoop for fun and prizes. This Maker, apparently unsatisfied with not having one of these at home, decided to duplicate the game with the “Pop o Shop.”

In this version, an ultrasonic sensor in the hoop tells an Arduino Nano when a shot has been registered, while two 7-segment displays inside of a LEGO scoreboard show the current count, time remaining, and high score. There is also an RGB LED that turns green after every made basket and changes color with a new top score.

Incidentally, one of the displays can also spell out “POPOSHOP,” which dictated the name of the game, since there is no “T” character in the LedControl library used! For more info and code, be sure to check out the “Internet of LEGO” build log!

Usually, when you think of doing “surgery” on electronics, it’s to replace a component, or maybe modifying an appliance into something different. In this case, an Arduino Nano powers Hurry, Doctor!, an updated version of the board game classic Operation meant as a middle school STEM exercise.

This game, of which creator “TrevorB23” gives an extensive explanation in his Instructables write-up, features a LEGO minifigure with cutouts inside that house obstructions such as a “mental block” and “funny bone.” As with the original, the objective is to remove these foreign bodies without touching the sides, constructed here with conductive aluminum foil tape in order to signal the Nano.

With its enhanced electronics, TrevorB23’s version adds a timing element to encourage “surgeons” to complete tasks faster, as well as doctor names and melodies that can be altered if so desired. Want to make your own game? You can follow along with his 31-step tutorial.

As entertaining as watching Netflix may be, you’re not burning a lot of calories while binging on your favorite shows. In order to do both at the same time, hacker “Roboro” modded a stationary exercise bike to stop streaming if he’s not maintaining his fitness goals.

Bicycle speed is derived from the signal that’s normally sent to the built-in display. He uses an Arduino Nano to hijack the square wave, and sends this info to the streaming computer serially via USB.

Starting the Python script and inputting some information, Firefox will start to stream Netflix and display in real-time for current workout information such as round, speed, nominal speed for this round and time to next round. If the user goes below the nominal speed for too long, Netflix will pause until the user has gotten back up to speed.

If you’d like to try this yourself, you can find an Instructables write-up with all the necessary details and check out his code on GitHub. Though designed around Netflix, Roboro notes that it can be used with other streaming services with a few changes.

After building a bicycle that could travel across town while making music, Sam Battle now taken things in a different direction. Synth Bike 3.0, which will be on display at the Science Center Dublin until September, is set up on a training fixture so that you can pedal it indoors rain or shine. This version also features a simplified control panel on the handlebars, allowing it to be played by anyone at a tempo controlled by the rear wheel’s speed.

Battle’s YouTube channel is named “LOOK MUM NO COMPUTER” however, this apparently doesn’t count microcontrollers. Hidden in the externally clean-looking handlebar groove box is a total of 12 Arduino Nano boards, along with a maze of wiring, strip circuit boards, frequency central PCBs, a SparkFun WAV trigger, and some other electronics. There’s even built-in speakers on the sides to output the created sounds.

Be sure to check out Synth Bike 3.0’s New Atlas write-up for more info on the project.

Computer vision has traditionally relied on an assortment of rather involved components. On the other hand, everything you need to do this complicated task is readily available on an Android phone. The clever setup seen in the video here uses a smartphone to capture and process images, then send out a signal over Bluetooth to tell which way the device needs to be adjusted in order to focus on a nearby face.

An HC-05 Bluetooth module receives this signal and passes it to two servo motors via an Arduino Nano, moving the phone left/right and up/down.

You can find the Arduino code for this project on CircuitDigest, and the Android Processing code can be downloaded there as a compressed folder.

Though time may be relative, unless you’re planning on doing a lot of space travel, slowing things down in real life is “notoriously” difficult. On the other hand, with carefully-coordinated vibrations and lighting, the “sLOMO” device is able to make objects such as a feather or plant appear to move in slow motion with the naked eye.

Inspired by Jeff Lieberman’s Slow Dance Frame, this project is made out of a readily available IKEA Ribba frame, and the object inside vibrates using an electromagnet. An Arduino Nano controls this magnet and pulses a double-row LED strip, in order to make the item appear to slow down, or even distort itself into multiple overlapping images.

Want to build your own? Check out the excellent write-up on Instructables, and see the magical frame in action below!