[Mike] saw a few videos of ultrasonic acoustic levitation rigs put together by student researchers. Figuring it couldn’t be that hard to replicate, he set out and built his own using surplus parts and whatever was sitting around his parts drawer.
The build began with a huge ultrasonic transducer from an old ultrasonic cleaning tank [Mike] picked up on eBay for
$20 £20. He didn’t pick up the standard driver board, as those don’t have a very clean output – something desperately needed if you’re setting up a standing wave. He did manage to put a simple supply together with a 555 timer, a MOSFET and a 12 V transformer connected backwards, though.
The test rig is pretty simple – just the transducer sitting on a table with an aluminum plate sitting above it on threaded rods. By adjusting the distance between the transducer to the aluminum plate, [Mike] managed to set up some standing waves he was able to suspend small Styrofoam balls in. It’s not quite precise enough to levitate small chunks of sodium and water, but it makes for an excellent science fair-type project.
Continue reading “DIY Ultrasonic acoustic levitation”
With his meteorological interests, [Carl] builds weather stations. Temperature and humidity sensors are a dime a dozen, but with his DIY ingenuity, [Carl] has built some very interesting and complicated devices. The latest of which is an ultrasonic wind sensor that uses the time of flight of ultrasonic pulses to detect how fast the wind is blowing.
[Carl]’s sensor uses four ultrasonic transducers aligned to North, South, East, and West to detect the wind speed. By measuring the time it takes an ultrasonic pulse to travel between the sensors indoors, Subtracting the in-situ measurement gives him the time of flight for each axis, and thus the wind speed.
It’s an impressive display of engineering that comes with an amazingly detailed design report. After three months of operation, [Carl] has found his ultrasonic anemometer is better than the traditional mechanical ‘egg-cup’ anemometer at measuring low wind speeds. The only real problem with the build is the fact the design makes a great bird perch, but some fine steel wire quickly corrected that problem.
We’ve got some friends who have two sump pumps. One is a backup and sounds an alarm when it is switched on. But this only works as long as they’re home to hear it. [Felix Rusu] came up with a solution what will text him if the sump pump fails. This way he can head home, or call someone to check in on the problem if he’s away.
We saw a pretty complicated monitoring system back in January. This one uses a single ultrasonic rangefinder which we think is much simpler. It’s accurate to about 1cm and is simple to use — it’s very popular with the hobby electronics crowd which helps with price and availability of sample code. We hem and haw about the use of a Raspberry Pi board with the project. On the one hand it’s a cheap way to get the sensor on the network and provides the infrastructure you need to send any number of alerts. On the other hand, it’s a lot of power for this particular application. But we figure it can be extended to monitor other utilities in [Felix’s] home, like a sensor to alert him of a leaking water heater. And we think everyone can argue that a monitor like this is well worth the time and effort he spent to develop it.
This little box not only plays tunes, but it lets you control several aspects of playback without touching a thing. [Thomas Clauser] calls it the LighTouch and we like it because it uses inaudible sound to control audible sound.
We think the pair of cylinders sticking up through the top of this project enclosure will be recognized by most readers as the business end of an ultrasonic rangefinder. This is the only control interface which [Thomas] chose to use. Although he didn’t write very extensively about the specific control scheme he implemented, the video embedded in his post shows some of the gestures that cause the Arduino inside to change its behavior. For instance, a swipe of the hand at higher level starts playback, swiping at a lower level pauses it. When adjusting the volume the box responds to how close his hand is to that sensor. With this control in place, the music side of these things is simply handled by a music shield he is using.
Hobby electronics from 1982
[Lennart] came across one of his projects from several decades ago. It’s a twinkling star which blinks LEDs at different rates using some 7400 logic chips and RC timers.
Solder fume extractor
We’re still blowing the solder fumes away from us using our mouth, but this might inspire us to do otherwise. It’s a large PC fan mounted on a lamp goose neck. It clamps to the bench and is quite easy to position.
Ultrasonic liquid level measurement
Wanting a way to measure the liquid in these tanks without submerging a sensor, [JO3RI] turned to an Arduino and an ultrasonic rangefinder. His method even allows the level to be graphed as shown in his Instructible about the project.
Adding an ‘On’ light to save batteries
Dumpster diving yielded this electronic drum machine for [MS3FGX’s] daughter to play with. The problem is that pushing any of the buttons turns it on, it doesn’t have an auto-off, and there’s no way to know when it’s on. This is unacceptable since it runs on 5 AA batteries. His quick fix adds this green On LED. We wonder if he’ll improve upon this and add an auto-off feature?
CMOS Binary Clock
This is a portion of the guts of [Dennis’] CMOS Binary Clock project from the early 2000’s. He even built a nice case with a window for the LEDs which you can see are mounted perpendicular to the protoboard.
The live Adafruit Show and Tell stream from last weekend featured this project put together by [Silent Jeff]. He’s called “Silent” because when it came time to present his project on the show his microphone wasn’t working. As you can see in the video after the break, [PT] and [Ladyada] worked together to explain the project (of which they had no prior knowledge) using a game of charades. This is one of the follow-up images he sent them which details his parking spotter project.
[Ladyada] compliments [Jeff] on the finished look of the device and we agree. Not only does this do a great job of letting a driver know if they have pulled far enough into the garage, but it’s finished appearance ensures it won’t ever look out-of-place. The two silver discs near the lower end of the box are the sensors of an ultrasonic rangefinder. You mount this box so that the sensor is measuring distance between itself and the bumper of your vehicle. As the distance decreases the LEDs change to let you know when to stop. Inside the case you’ll find a voltage regulator and single-chip running the Arduino bootloader. [Jeff] says this is just his second Arduino project and we hope that at this rate we’ll be looking for big things from him in the not too distant future!
This is basically the same idea as cars that use parking assist sensors in the bumper. It’s just attached to the building instead of to the vehicle itself.
Continue reading “Garage parking monitor guides you in every time”
[Andreas] wrote in to let us know about this DIY Neurophone project. Apparently a Flanagan Neurophone uses ultrasound in some manner to transmit audio directly to the body, or nervous system? Needless to say we are a bit skeptical of anyone whose wiki page leads directly to pyramid power. In fact most of the references to this thing start rambling about some pretty pseudo-scientific theories.
At any rate, the schematic is clear and simple enough for anyone who has the parts to easily try. The only challenge might be tuning the thing with a signal generator or audio feed. So how about it, any one have a TL494 pulse-width modulation controller and want to be a guinea pig?