Ultrasonic Array Gets Range Data Fast and Cheap

How’s your parallel parking? It’s a scenario that many drivers dread to the point of avoidance. But this 360° ultrasonic sensor will put even the most skilled driver to shame, at least those who pilot tiny remote-controlled cars.

Watch the video below a few times and you’ll see that within the limits of the test system, [Dimitris Platis]’ “SonicDisc” sensor does a pretty good job of nailing the parallel parking problem, a driving skill so rare that car companies have spent millions developing vehicles that do it for you. The essential task is good spatial relations, and that’s where SonicDisc comes in. A circular array of eight HC-SR04 ultrasonic sensors hitched to an ATmega328P, the SonicDisc takes advantage of interrupts to make reading the eight sensors as fast as possible. The array can take a complete set of readings every 10 milliseconds, which is fast enough to allow for averaging successive readings to filter out some of the noise that gets returned. Talking to the car’s microcontroller over I2C, the sensor provides a wealth of ranging data that lets the car quickly complete a parallel parking maneuver. And as a bonus, SonicDisc is both open source and cheap to build — about $10 a copy.

Rather use light to get your range data? There are some pretty cheap LIDAR units on the market these days.

Continue reading “Ultrasonic Array Gets Range Data Fast and Cheap”

Hackaday Prize Entry: Sonic Glasses

This year, the Hackaday Prize is going to find the most innovative and interesting assistive technologies. Whether that’s refreshable Braille displays or reliable utensils for the disabled, the finalists for the Assistive Technologies portion of the Prize will be creating some of the most interesting tech out there.

For his entry into the Assistive Technology part of the Prize, [Pawit] is building binaural glasses for the blind. It’s difficult to navigate unknown environments without a sense of sight, and these SonicScape glasses turn cheap distance sensors into head-mounted sonar.

The glasses are built around a pair of ultrasonic distance sensors (the HC-SR-04, if you’re curious), mounted in a convenient 3D-printed enclosure that looks sufficiently like a pair of glasses to not draw too many glares. (Although maybe we’d print them in black to lower the contrast.) Of note in this project is the Bluetooth connectivity to eliminate wires and independent left and right audio channels. That last bit — being able to hear in left and right — is something we haven’t seen before in devices like this and aims to greatly increase the usability of such a device.

Floating Ants and Drops of Liquid with an Acoustic Levitator

Amuse your friends, amaze your enemies, and perplex ants and other insects, insofar as they are capable of perplexment. Accomplish all this and more with this handy dandy homebrew acoustic levitator.

Before anyone gets to thinking about using this technique to build a hoverboard that actually hovers, it’s best that you scale your expectations way, way down. Still, being able to float drops of liquid and small life forms is no mean feat, and looks like a ton of fun to boot. [Asier Marzo]’s Instructable’s post fulfills a promise he made when he first published results for what the popular press then breathlessly dubbed a “tractor beam,” which we covered back in January. This levitator clearly has roots in the earlier work, what with 3D-printed hemispherical sections bristling with ultrasonic transducers all wired in phase. A second section was added to create standing acoustic waves in the middle of the space, and as the video below shows, just about anything light enough and as least as cooperative as an ant can be manipulated in the Z-axis.

There’s plenty of room to expand on [Asier]’s design, and probably more practical applications than annoying bugs. Surface-mount devices are pretty tiny — perhaps an acoustic pick and place is possible?

Continue reading “Floating Ants and Drops of Liquid with an Acoustic Levitator”

Garage Distance Sensor Kicks Tennis Ball To Curb

Those with small garages might be familiar with the method of hanging a tennis ball from a ceiling to make sure they don’t hit the back wall with their car. If the car isn’t in the garage, though, the tennis ball dangling from a string tends to get in the way. To alleviate this problem, [asaucet] created a distance sensor that can tell him when his car is the perfect distance from the garage wall.

At the heart of the distance sensor is an HC-SR04 ultrasonic rangefinder and a PIC16F88 microcontroller. [asaucet] uses a set of four LEDs to alert the driver how close they are to the garage wall. [asaucet] also goes into great detail about how to use an LCD with this microcontroller for setting up the project, and the amount of detail should be enough to get anyone started on a similar project.

While this isn’t a new idea, the details that [asaucet] goes into in setting up the microcontroller, using the distance sensor, and using an LCD are definitely worth looking into. Even without this exact application in mind, you’re sure to find some helpful information on the project page.

Continue reading “Garage Distance Sensor Kicks Tennis Ball To Curb”

Quick Hack Cleans Data from Sump Pump

Nobody likes to monitor things as much as a hacker, even mundane things like sump pumps. And hackers love clean data too, so when [Felix]’s sump pump water level data was made useless by a new pump controller, he just knew he had to hack the controller to clean up his data.

Monitoring a sump pump might seem extreme, but as a system that often protects against catastrophic damage, the responsible homeowner strives to take care of it. [Felix] goes a bit further than the average homeowner, though, with an ultrasonic sensor to continually measure the water level in the sump and alert him to pending catastrophes. Being a belt and suspenders kind of guy, he also added a float switch to control the pump, but found that the rapid cycle time made his measurements useless. Luckily the unit used a 555 timer to control the pump’s run time after triggering, so a simple calculation of the right RC values and a little solder job let him increase the on time of the pump. The result: a dry basement and clean data.

We recently discussed the evolution of home automation if you want to know more about the systems that sensors and actuators like these can be part of. Or for a more nuts and bolts guide to networking things together, our primer on MQTT might help.

Measuring Air Flow with Ultrasonic Sensors

Measuring air flow in an HVAC duct can be a tricky business. Paddle wheel and turbine flow meters introduce not only resistance but maintenance issue due to accumulated dust and debris. Being able to measure ducted airflow cheaply and non-intrusively, like with this ultrasonic flow meter, could be a big deal for DIY projects and the trades in general.

The principle behind the sensor [ItMightBeWorse] is working on is nothing new. He discovered a paper from 2015 that describes the method that measures the change in time-of-flight of an ultrasonic pulse across a moving stream of air in a duct. It’s another one of those “Why didn’t I think of that?” things that makes perfect sense in theory, but takes some engineering to turn into a functional sensor. [ItMightBeWorse] is using readily available HC-SR04 sensor boards and has already done a proof-of-concept build. He’s getting real numbers back and getting close to a sensor that will go into an HVAC automation project. The video below shows his progress to date and hints at a follow-up video with more results soon.

Here’s wishing [ItMightBeWorse] the best of luck with his build. But if things go sideways, he might look to our post-mortem of a failed magnetic flow meter for inspiration.

Continue reading “Measuring Air Flow with Ultrasonic Sensors”

Graphene from Graphite by Electrochemical Exfoliation

Graphene is an interesting material, but making enough of the stuff to do something useful can be a little tough. That’s why we’re always on the lookout for new methods, like this electrochemical process for producing graphene in bulk.

You probably know that graphene is a molecular monolayer of carbon atoms linked in hexagonal arrays. Getting to that monolayer is a difficult proposition, but useful bits of graphene can be created by various mechanical and chemical treatments of common graphite. [The Thought Emporium]’s approach to harvesting graphene from graphite is a two-step process starting with electrochemical exfoliation. Strips of thin graphite foil are electrolyzed in a bath of ferrous sulfate, resulting in the graphite delaminating and flaking off into the electrolyte. After filtering and cleaning, the almost graphene is further exfoliated in an ultrasonic cleaner. The result is gram quantity yields with very little work and at low cost.

There’s plenty of effort going into new methods of creating graphene these days, whether by barely controlled explosions or superheating soybean oil. But will graphene be the Next Big Thing? The jury is still out on that.

Continue reading “Graphene from Graphite by Electrochemical Exfoliation”