Arduino-Powered Missile System Uses Ultrasound To Aim

June 13, 2023 by Lewin Day 14 Comments

In the real world, missile systems use advanced radars, infrared sensors, and other hardware to track and prosecute their targets. [Raspduino Uno] on YouTube has instead used ultrasound for targeting for an altogether simpler desktop fire control solution.

This fun build uses a common off-the-shelf USB “missile launcher” that fires foam darts. To supply targeting data for the launcher, an Arduino Uno uses an ultrasonic sensor pair mounted atop a servo. As the servo rotates, the returns from the ultrasonic sensor are plotted on a screen run by a Raspberry Pi. If an object is detected in the 180-degree field of view of the sweeping sensor, a missile is fired using the dart launcher.

It’s a relatively simple build, but nonetheless would serve as a useful classroom demonstration of radar-like targeting techniques to a young audience. Real military hardware remains altogether more sophisticated. Video after the break.

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Lego Guitar Is Really An Ultrasonically-Controlled Synth

January 26, 2023 by Lewin Day 4 Comments

The phrase “Lego Guitar” can be a stressful one to hear. You might imagine the idea of strings under tension and a subsequently exploding cloud of plastic shrapnel. This build from the [Brick Experiment Channel] eschews all that, thankfully, and is instead a digital synth that only emulates a guitar in its rough form factor.

The heart of the build is a Lego Mindstorms EV3 controller. It’s acts as the “body” of the guitar, and is fitted with a Lego “fretboard” of sorts. A slide is moved up and down the fretboard by the player. The EV3 controller detects the position of the slide via an ultrasonic sensor, and uses this to determine the fret the user is trying to play. The button the user presses on the controller then determines which of five “strings” the user is playing, and the selected note is sounded out from the EV3’s internal speaker. It’s strictly a monophonic instrument, but three different sounds are available: a bass guitar, a rock guitar, and a solo guitar, with all the fidelity and timbre of a 90s Casio keyboard.

It’s a fun and silly instrument, and also kind of difficult to play. The slide mechanism doesn’t offer much feedback, nor are the EV3 buttons intended for dynamic musical performance. Regardless, the player belts out some basic tunes to demonstrate the concept. We doubt you’d ever be able to play Through The Fire and Flames on such a limited instrument, but [Brick Experiment Channel] used their editing skills to explore what that might sound like regardless.

We’ve seen some other great synth guitars before, too. Modern microcontrollers and electronics give makers all kinds of creative ways to build electronic instruments with unique and compelling interfaces. Some are more successful than others, but they’re all fun to explore. Video after the break.

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Open Source Ultrasonic Anemometer

July 6, 2021 by Danie Conradie 12 Comments

Weather stations are a popular project for experimenting with various environmental sensors, and for wind speed and direction the choice is usually a simple cup anemometer and wind vane. For [Jianjia Ma]’s QingStation, he decided to build another type of wind sensor: An ultrasonic anemometer.

Ultrasonic anemometers have no moving parts but come at the cost of significantly more electronic complexity. They work by measuring the time it takes for an ultrasonic audio pulse to be reflected the receiver across a known distance. Wind direction can be calculated by taking velocity readings from two ultrasonic sensor pairs perpendicular to each other and using a bit of simple trigonometry. For an ultrasonic anemometer to work properly, it requires a carefully designed analog amplifier on the receive side and a lot of signal processing to extract the correct signal from all the noise caused by secondary echoes, multi-pathing, and the environment. The design and experimentation process is well-documented. Since [Jianjia] does not have access to a wind tunnel for testing and calibration, he improvised by mounting the anemometer on his car’s roof and going for a drive. This yielded readings that were proportional to the car’s GPS speed, but a bit higher. This might due to a calculation error, or external factors like wind, or disturbed airflow from the test car or other traffic.

Other sensors include an optical rain sensor, light sensor, lighting sensor, and a BME280 for air pressure, humidity, and temperature. [Jianjia] plans to use the QingStation on an autonomous boat, so he also included an IMU, compass, GPS, and a microphone for environmental sounds. The fact that none of the sensors have moving parts is a major advantage for this use case, and we look forward to seeing the boat project. All the hardware and software are open-source and available on GitHub.

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Parking Assistant Helps Back Up The Car Without Going Too Far

September 27, 2020 by Kristina Panos 24 Comments

Sure, [Ty Palowski] could have just hung a tennis ball from the ceiling, but that would mean getting on a ladder, testing the studfinder on himself before locating a ceiling joist, and so on. Bo-ring. Now that he finally has a garage, he’s not going to fill it with junk, no! He’s going to park a big ol’ Jeep in it. Backwards.

The previous owner was kind enough to leave a workbench in the rear of the garage, which [Ty] has already made his own. To make sure that he never hits the workbench while backing into the garage, [Ty] made an adorable stoplight to help gauge the distance to it. Green mean’s he’s good, yellow means he should be braking, and red of course means stop in the name of power tools.

Inside the light is an Arduino Nano, which reads from the ultrasonic sensor mounted underneath the enclosure and lights up the appropriate LED depending on the car’s distance. All [Ty] has to do is set the distance that makes the red light come on, which he can do with the rotary encoder on the side and confirm on the OLED. The distance for yellow and green are automatically set from red — the yellow range begins 24″ past red, and green is another 48″ past yellow. Floor it past the break to watch the build video.

The humble North American traffic signal is widely recognized, so it’s a good approach for all kinds of applications. Teach your children well: start them young with a visual indicator of when it’s okay to get out of bed in the morning.

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Contactless Doorbell Built To Avoid Coronavirus

June 4, 2020 by Lewin Day 15 Comments

It’s often said that necessity breeds creativity, and during a global pandemic such words have proved truer than ever. Realising the common doorbell could be a potential surface transmission point for coronavirus, [CasperHuang] whipped up a quick build.

The build eschews the typical pushbutton we’re all familiar with. Instead, it relies on an ultrasonic distance sensor to detect a hand (or foot) waved in front of the door. An Arduino Leonardo runs the show, sounding a buzzer when the ultrasonic sensor is triggered. In order to avoid modifying the apartment door, the build is housed in a pair of cardboard boxes, taped to the base of the door, with wires passing underneath.

It’s a tidy way to handle contactless deliveries. We imagine little touches like this may become far more common in future design, as the world learns lessons from the COVID-19 pandemic. Every little bit helps, after all. Video after the break.

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Get Quarantine Fit With This Smart Pull-up Bar

May 4, 2020 by Tom Nardi 16 Comments

Most gyms are closed right now due to social distancing rules, which is what we’re using as our latest excuse to justify our sloth-like lifestyle. But apparently some people miss working out enough that they’re putting together impromptu home gyms. [Michael Pick] has even outfitted his DIY pull-up station with an Arduino to keep track of his exercise while on lockdown. You may not like it, but this is what peak performance looks like.

In the video after the break, [Michael] explains the design and construction of the bar itself which technically could be thought of as its own project. Obviously the Arduino counter isn’t strictly necessary, so if you just wanted to know how to put some scraps of wood and suitably beefy rod together in such a way that it won’t rip off the wall when you put your weight on it, this video is for you.

Towards the end of the video, he gets into an explanation of the electronic side of the project. Inside the 3D printed enclosure is an Arduino Pro Mini, a HC-SR04 ultrasonic sensor, and a 1602 serial LCD. Once the gadget has been mounted in the proper position and activated, it will count how many pull-ups [Michael] has done on the screen.

While we historically haven’t seen a whole lot in the way of homebrew exercise equipment, the current COVID-19 situation does seem to be getting the adrenaline flowing for some of you. We recently covered some DIY dumbbells made from hardware store finds that would be an excellent first project for any hackers who’ve recently been ejected from the Matrix and are trying to use their muscles for the first time.

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Ultrasonic Sensor Helps You Enforce Social Distancing

April 9, 2020 by Erin Pinheiro 22 Comments

If you’re going outside (only for essential grocery runs, we hope) and you’re having trouble measuring the whole six feet apart from other people deal by eye, then [Guido Bonelli] has a solution for you. With a standard old HC-SR04 ultrasonic sensor, an audio module and a servo to drive a custom gauge needle he’s made a device which can warn people around you if they’re too close for comfort.

As simple as this project may sound like for anyone who has a bunch of these little Arduino-compatible modules lying around and has probably made something similar to this in their spare time, there’s one key component that gives it an extra bit of polish. [Guido] found out how intermittent the reliability of the ultrasonic sensor was and came up with a clever way to smooth out its output in order to get more accurate readings from it, using a bubble sort algorithm with a twist. Thirteen data points are collected from the sensor, then they are sorted in order to find a temporal middle point, and the three data points at the center of that sort get averaged into the final output. Maybe not necessarily something with scientific accuracy, but exactly the kind of workaround we expect around these parts!

Projects like these to help us enforce measures to slow the spread of the virus are probably a good bet to keep ourselves busy tinkering in our labs, like these sunglasses which help you remember not to touch your face. Make sure to check out this one in action after the break!

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