Fail of the Week: Sonar Submersibility Sealing

For the last decade or so, [Jason] has wanted to build an underwater robot. Can you blame him? More recently, he’s been researching sonar sensing and experimenting with the relatively inexpensive HC-SR04 module. Since he had good luck getting it to work with a PC sound card and a Stellaris Launchpad, he figured it was time to try using it underwater.

Hydrophone research led him to the idea of submerging the sensor in mineral water oil to both seal it and couple it with the water. Unfortunately, the HC-SR04 only sends one pulse and waits for echo. Through the air, it reliably and repeatedly returned a small value. Once inside a pill bottle filled with mineral oil, though, it does something pretty strange: it fluctuates between sending back a very small value and an enormous value. This behavior has him stumped, so he’s going to go back to the Launchpad unless you can help him figure out what’s going on. Should he use a different method to seal it?


2013-09-05-Hackaday-Fail-tips-tileFail of the Week is a Hackaday column which runs every Thursday. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Sonar With Python and Conference Call Hardware

conference-call-sonar

[Jason] just tipped us off about his recent experiment, in which he creates a sonar system using standard audio equipment and a custom Python program. In case some of our readers don’t already know it, Sonar is a technique that uses sound propagation to detect objects on or under the surface of the water. It is commonly used in submarines and boats for navigation. [Jason]’s project uses active sonar, which consists in sending short audio bursts (chirps) and listening for echoes. The longer it takes for the echo to return, the further the object is. Though his proof of concept is not used underwater, that may change if he continues the project.

The audio editing software Audacity was used to make a fast frequency changing chirp, along with PyAudio libraries for the main Python program. Exact time of arrival is detected by correlating the microphone output with the transmitted signal. Given that [Jason] uses audible frequencies, we think that the final result shown in the video embedded below is quite nice.
Continue reading “Sonar With Python and Conference Call Hardware”

A think-tank solution for monitoring radioactive water storge tanks

SONY DSC

When we hear reports of radioactive water leaking into the ocean from the [Fukushima Dai-Ichi] plant in Japan we literally have to keep ourselves from grinding our teeth. Surly the world contains enough brain power to overcome these hazards. Instead of letting it gnaw at him, [Akiba] is directing his skills at one solution that could help with the issue. There are a number of storage tanks on site which hold radioactive water and are prone to leaking. After hearing that they are checked manually each day, with no automated level monitoring, he got to work. Above is the wireless non-contact tank level sensor rig he built to test out his idea.

A couple of things made this a quick project for him. First off, he just happened to have a MaxSonar MB7389 waterproof sonar sensor on hand. Think of this as a really fancy PING sensor that is water tight and can measure distance up to five meters. [Akiba’s] assumption is that the tanks have a hatch at the top into which this sensor would be positioned. The box next to it contains a Freakduino of his own design which includes hardware for wireless communications at 900 MHz. This is the same hardware he used for that wireless toilet monitor.

We really like seeing hacker solutions to environmental problems. A prime example is some of the cleanup hacks we saw around the time of the BP Gulf of Mexico oil spill.

 

A Robotic Turtle Platform to Buy or Build

This electric turtle bot instructable describes a fairly simple turtle-style robot meant to be laser cut out of acrylic (although other materials such as aluminum, MDF, or polycarbonate should work just as well). This frame is also optionally for sale, which should appeal to those that would like a mechanical robotics platform to play with, but don’t have access to machine tools. The build instructions include a detailed bill of materials which should come in handy.

As displayed in the video after the break, the robot uses a sonar sensor to navigate. This sensor is set up on a servo in order to scan the terrain, and, depending on how it’s programmed, hopefully avoid obstacles. As of when the video was taken, the little robot appears to sense an obstacle then scan with the servo left and right to see what the best way to turn is.

If this little turtle robot doesn’t have enough power for your taste, check out this autonomous ATV sentry.

Autonomous rover roams the halls

[ESylin] built an autonomous rover that roams the vacant halls of his school. On the hood of the vehicle he’s mounted two Maxbotix sonar sensors that do a great job of keeping the vehicle centered in the hallway. It will follow a wall around a corner (favoring its left side because of the left-facing sensor) and it will stop to correct itself if it gets off course. That’s because when you’re not driving a dsPIC33 is, with a Traxxas XL-5 speed controller and a hobby servo for steering. But this little guy hasn’t lost all his pep. Manual control and be switched on from from an R/C controller so you can burn up the floor tiles. Take a look at the demo after the break, with the manual control demo shown at about 4:10. Continue reading “Autonomous rover roams the halls”

Intelligent Ground Vehicle Competition 2010 Day One Report

The Intelligent Ground Vehicle Competition (IGVC) is the precursor to the DARPA Grand Challenge, and in many ways it is just as difficult. We have the pleasure of being at the competition this year with the Tennessee Technological University Autonomous Robotics Team. The teams at the competition pull off some amazing home-brew robotics, so we’ve decided to do a short section on some exemplary robotic hacking each day of the competition.

Today’s robot comes from the York College of Pennsylvania. The robot, dubbed “Green Lightning”, features an impressive set of custom made hardware.

We interviewed the team, and got a pretty thorough rundown of their robot with pictures after the jump. Continue reading “Intelligent Ground Vehicle Competition 2010 Day One Report”

Rotating radar visualization

We ask, who wouldn’t want a rotating motion and distance tracking radar? Sure in today’s day and age anyone could purchase a wide-angle sonar or IR solution that achieves the same goal, but [LuckyLarry] took it old school and made his own rotating radar. He used an Arduino, servo, and ultrasonic sensor as a base to gather data, and the open source programming language Processing to draw the data on the screen. He says it’s a little inaccurate currently, but will try out some other sensors in the future.