Posts with «ultrasonic» label

Dead Simple Ultrasonic Data Communication

Some of the best hacks are the ones which seem perfectly obvious in hindsight; a solution to the problem that’s so elegant, you wonder how it never occurred to you before. Of course we also love the hacks that are so complex your eyes start to water, but it’s nice to have a balance. This one, sent in by [Eduardo Zola] is definitely in the former group.

In the video after the break, [Eduardo] demonstrates his extremely simple setup for using ultrasonic transducers for one-way data communication. Powered by a pair of Arduinos and using transducers salvaged from the extremely popular HC-SR04 module, there’s a good chance a lot of readers can recreate this one on their own bench with what they’ve got lying around. In this example he’s sending strings of text from one computer to another, but with a little imagination this can be used for all sorts of projects.

For the transmitter, the ultrasonic transducer is simply tied to one of the digital pins on the Arduino. The receiver is a bit more complex, requiring a LM386 amplifier and LM393 comparator to create a clean signal for the second Arduino to read.

But how does it work? Looking through the source code for the transmitter and receiver, we can see it’s about as basic as it gets. The transmitter Arduino breaks down a given string into individual characters, and then further converts the ASCII to eight binary bits. These bits are sent out as tones, and are picked up on the receiving end. Once the receiver has collected a decent chunk of tones, it works through them and turns the binary values back into ASCII characters which get dumped over serial. It’s slow, but it’s simple.

If you’re looking for something a bit more robust, check out this guide on using GNU Radio with ultrasonics.

Listening for Hand Gestures

[B. Aswinth Raj] wanted to control a VLC player with hand gestures. He turned to two common ultrasonic sensors and Python to do the job. There is also, of course, an Arduino. You can see a video of the results, below.

The Arduino code reads the distance from both sensors — one for the left hand and the other for the right. This allows the device to react to single hand gestures that get closer or further away from one sensor as well as gestures involving both hands. For example, raising your left hand and moving it closer or further away will adjust the volume. The right hand controls rewind and fast forward. Raising both hands will start or stop playback.

Of course, since the Arduino is reading the gestures you could change them to suit you. We might have mounted the sensors further back (or, perhaps, added more sensors) so you could use trigonometry to triangulate the hand’s exact position. Well, perhaps not exact, but you could get an idea of the hand’s motion from right to left as well as forward and backward.

On the host computer side, Python receives serial data from the Arduino and then simulates keystrokes to get the desired result. Of course, this is also highly customizable.

By coincidence, we did a similar project a few years ago using one sensor and the Arduino’s ability to appear like a USB keyboard. We’ve also seen 8 sensors making piano music.


Filed under: Arduino Hacks
Hack a Day 02 Nov 03:00

Fire Fighting Robot

Primary image

What does it do?

Navigate a Maze, extinguish a flame, track position

I'm currently a sophomore at Worcester Polytechnic Institute studying Robotics Engineering. The third course in the series, RBE 2002, focusing on sensors. In a group of 4 students, we built a robot that could autonomously navigate a maze, locate a flame, put it out and report its X,Y, and Z position relative to its starting position. The robot was required to use an IMU and a flame sensor provided to us. All other sensors and parts are up to the group to use to complete the challenge.

Cost to build

Embedded video

Finished project

Complete

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Fire Fighting Robot

Primary image

What does it do?

Navigate a Maze, extinguish a flame, track position

I'm currently a sophomore at Worcester Polytechnic Institute studying Robotics Engineering. The third course in the series, RBE 2002, focusing on sensors. In a group of 4 students, we built a robot that could autonomously navigate a maze, locate a flame, put it out and report its X,Y, and Z position relative to its starting position. The robot was required to use an IMU and a flame sensor provided to us. All other sensors and parts are up to the group to use to complete the challenge.

Cost to build

Embedded video

Finished project

Complete

Number

Time to build

Type

URL to more information

Weight

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WALTER - The Arduino Photovore Insect Robot

Primary image

What does it do?

Navigate around and seeking light

[Please excuse my English]

Cost to build

Embedded video

Finished project

Complete

Number

Time to build

Type

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WALTER - The Arduino Photovore Insect Robot

Primary image

What does it do?

Navigate around and seeking light

[Please excuse my English]

Cost to build

Embedded video

Finished project

Complete

Number

Time to build

Type

URL to more information

Weight

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WALTER - The Arduino Photovore Insect Robot

Primary image

What does it do?

Navigate around and seeking light

[Please excuse my English]

Cost to build

Embedded video

Finished project

Complete

Number

Time to build

Type

URL to more information

Weight

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WALTER - The Arduino Photovore Insect Robot

Primary image

What does it do?

Navigate around and seeking light

[Please excuse my English]

Cost to build

Embedded video

Finished project

Complete

Number

Time to build

Type

URL to more information

Weight

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EG First 2nd rev bot

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What does it do?

Modified RC obstacle avoidance Car

Very new to this site. Been playing with this project on and off for 6 months. Completed once then went back to and it wasn't working. Tried to troubleshoot and burnt out the chip. Pulled out the whole circuit board. Then rewired the battery pack. At that point it is just the frame DC motors on front and back(front geared to turn right and left, back left as dc motor for fowards and back) . I pulled an H bridge chip from a motor drive expansion board and breadboarded it .

Cost to build

Embedded video

Finished project

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Ultrasonic Collision Avoidance Arduino and Raspberry Pi

Hi;

I am building and testing a telepresence wheeled rover bot that has two methods of control:

1. Web Interface (Manual Mode): This consists of a control panel on a web page served using WebIOPi on a Raspberry Pi which, when activated, sends commands to an Arduino Nano AT Mega328P via a two wire i2c interface (Forward, Back etc). 

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