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.

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!

[Nubmian] wrote in to share his experiments with measuring airflow in an HVAC system. His first video deals with using with ultrasonic sensors. He found an interesting white paper that described measuring airflow with a single-path acoustic transit time flow meter. The question was, could he get the same effects with off-the-shelf components?

[Nubmian] created a rig using a pair of typical ultrasonic distance sensors. He detached the two transducers from the front of the PCB. The transducers were then extended on wires, with the “send” capsules together pointing at the “receive” capsules. [Nubmian] set the transducers up in a PVC pipe and blew air into it with a fan.

In his second video, [Nubmian] sets up a test rig consisting of a multimeter connected to an airflow sensor. The multimeter is soon replaced by an Arduino with the help of an AD623ARZ amp. The wires for that setup needed some shielding. Aluminum foil connected to the ground did the trick.

For more HVAC projects check out this pinwheel flow meter and [Adam]’s piece on HVAC techs, hackers who make house calls.

Digital White/Black Boards or “Smart Boards” are very useful in modern classrooms, but their high cost often makes it difficult to convince administrators from loosening their purse strings. Cooper Union’s 2nd annual HackCooper event in New York wanted students to design and build hardware and software projects that both solve real problems and spark the imagination. At the 24 hour hackathon, the team of [harrison], [david] and [caleb] decided to put together a low-cost and simple solution to digitizing classroom black board content.

A chalk-holder is attached to two strings, each connected over a pulley to a weight. The weights slide inside PVC pipes at the two sides of the black board. Ultrasonic sensors at the bottom of each tube measure the distance to the weights. The weights sit in static equilibrium, so they serve the purpose of keeping the string taut without negatively interfering with the writer.

With a couple of calibration points to measure the extent of displacement of each weight, board width can be determined, making it easy to adapt to different sizes of boards. Once calibrated, the system can determine position of the chalk over the board based on some trigonometrical calculations. Since they had just 24 hours to hack the system together, they had to use a hand operated radio with a couple of buttons to provide user control. Pressing the “Write” button starts transmitting chalk movements to the digital screen. A second button on the radio remote serves to “Erase” the digital screen. After receiving the chalk position data, they had to do a fair amount of processing to eliminate noise and smooth out the writing on the digital screen.

A server allows the whole class to receive the chalk board data in real time. After each “Erase” command, the chalk board state is saved and logged on the server, thus allowing previous content to be viewed or downloaded. If only text is written, optical character recognition can be used to further digitize the content.

What makes the project really useful is the low cost. The sensors cost a dollar. The other parts – PVC pipe, weights/pulleys, Arduino and the Radio key fob – were all bought for under 40 dollars. For some additional cost (and maybe more time in their case) they could have automated the detection of when the chalk was actually doing the writing. The team have made their code available on Github. For a Chalk board at the other end of the cost spectrum, check this one out. Video below.

Fans of the bouncing lamp from the Pixar corporate logo will enjoy [Daniel]‘s latest project. It’s a motion controlled desk lamp that uses ultrasonic sensors to control its physical position.

The core of the project is an Arduino and the three ultrasonic sensors. The sensors act as range finders, and when they are all working together under the direction of the microcontroller they can tell which direction a hand was moving when it passed by. This information is used to drive two servos, one in the base and one on the lamp’s arm.

The project requires an articulating desk lamp of some sort (others besides the specific one [Daniel] used shouldn’t be much of a problem as long as they bend in the same way). Most hackers will have the rest of the parts on hand, with the possible exception of the rangefinder. The code is up on the project site for a look-see or in case you want to build your own.

The only problem that [Daniel] had when putting this all together was that the base was a little wobbly. He was able to fix that with some thumbtacks, and we think the next step for the project should be switching the light on and off over the internet.

Producing items onto a screen simply by touching the air is a marvelous thing. One way to accomplish this involves four HC-SR04 ultrasonic sensor units that transmit data through an Arduino into a Linux computer. The end result is a virtual touchscreen that can made at home.

The software of this device was developed by [Anatoly] who translated hand gestures into actionable commands. The sensors attached to the Arduino had a an approximate scanning range of 3m, and the ultrasonic units were modified to broadcast an analog signal at 40 kHz. There were a few limitations with the original hardware design as [Anatoly] stated in the post. For example, at first, only one unit was transmitting at a time, so there was no way the Arduino could identify two objects on the same sphere. However, [Anatoly] updated the blog with a 2nd post showing that sensing multiple items at once could be done. Occasionally, the range would be finicky when dealing small items like pens. But besides that, it seemed to work pretty well.

Additional technical specifications can be found on [Anatoly]‘s blog and videos of the system working can be seen after the break.

[Thanks for the tip João!]

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I managed to finish my first robot on witch I spent a lot of time, mostly because a lot of stuff was new to me. It is not very complicated but it seems to do it's job well. I posted everything about the build on my blog and also the parts I used (and the ones I rejected).

It is a Tamiya tracked platform with dual gearbox. I used an Arduino UNO and a SeeedStudio motor shield to drive it from a 11.7 lipo battery I had from my RC heli. It uses a Ultrasonic sensor to look in front and also a DIY IR sensor for backing up. I also added a temperature sensor for the fun of it.

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Hello,

Greetings from Hong Kong.

This is my first Arduino project. I have worked with the handyboard and NXT few years ago. The Arduino seems popular and easy to get into for people from non-electronic background like me, so I decided to build something simple to get myself familiarize with the Arduino board and interfaces. For the look I decided to make it the Minecraft Creeper, for the non-gamers, it's a iconic mob that appears in the 8-bit inspired 3D game Minecraft. If you havent try it before, grab a copy now! 

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