DTMF Robot Makes Rube Goldberg Proud

May 27, 2016 by 11 Comments

Sometimes you start building, and the project evolves. Layers upon layers of functionality accrue, accrete, and otherwise just pile up. Or at least we’re guessing that’s what happened with [Varun Kumar]’s sweet “Surveillance Car Controlled by DTMF“.

In case you haven’t ever dug into not-so-ancient telephony, Dual-tone, multi-frequency signalling is what made old touch-tone phones work. DTMF, as you’d guess, encodes data in audio by playing two pitches at once. Eight tones are mapped to sixteen numbers by using a matrix that looks not coincidentally like the old phone keypad (but with an extra column). One pitch corresponds to a column, and one to a row. Figure out which tones are playing, and you’ve decoded the signal.

Anyway, you can get DTMF decoder chips for pennies on eBay, and they make a great remote-control interface for a simple robot, which is presumably how [Varun] got started. And then he decided that he needed a cell phone on the robot to send back video over WiFi, and realized that he could also use the phone as a remote controller. So he downloaded a DTMF-tone-generator app to the phone, which he then controls over VNC. Details on GitHub.

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Badge builder's meetup at DC27

Pictorial Guide To The Unofficial Electronic Badges Of DEF CON 27

September 19, 2019 by 15 Comments

DEF CON has become the de facto showplace of the #Badgelife movement. It’s a pageant for clever tricks that transform traditional green rectangular circuit boards into something beautiful, unique, and often times hacky.

Today I’ve gathered up about three dozen badge designs seen at DC27. It’s a hint of what you’ll see in the hallways and meetups of the conference. From hot-glue light pipes and smartphone terminal debugging consoles to block printing effects and time of flight sensors, this is a great place to get inspiration if you’re thinking of trying your hand at unofficial badge design.

If you didn’t catch “The Badgies” you’ll want to go back and read that article too as it rounds up the designs I found to be the craziest and most interesting including the Car Hacking Village, Space Force, SecKC, DC503, and Frankenbadge. Do swing by the Hands-On articles for the AND!XOR badge and for [Joe Grand’s] official DC27 badge. There was also a lot of non-badge hardware on display during Hackaday’s Breakfast at DEF CON so check out that article as well.

Enough preamble, let’s get to the badges!

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Wireless Controllers For Retro Gaming

April 8, 2019 by 5 Comments

There’s no limit to the amount of nostalgia that can be minted through various classic platforms such as the NES classic. The old titles are still extremely popular, and putting them in a modern package makes them even more accessible. On the other hand, if you still have the original hardware things can start getting fussy. With modern technology it’s possible to make some changes, though, as [PJ Allen] did by adding wireless capabilities to his Commodore 64.

Back when the system was still considered “modern”, [PJ] tried to build a wireless controller using DTMF over FM radio. He couldn’t get it to work exactly right and ended up shelving the project until the present day. Now, we have a lot more tools at our disposal than analog radio, so he pulled out an Arduino and a few Bluetooth modules. There’s a bit of finesse to getting the old hardware to behave with the modern equipment, though, but once [PJ] worked through the kinks he was able to play his classic games like Defender without the limitations of wired controllers.

The Commodore 64 was incredibly popular in the ’80s and early ’90s, and its legacy is still seen today. People are building brand new machines, building emulators for them, or upgrading their hardware.

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Cell Phone Surveillance Car

January 30, 2018 by 15 Comments

There are many viable options for home security systems, but where is the fun in watching a static camera feed from inside your place? The freedom to really look around might have been what compelled [Varun Kumar] to build a security car robot to drive around his place and make sure all is in order.

Aimed at cost-effectiveness and WiFi or internet accessibility, an Android smartphone provides the foundation of this build — skipping the need for a separate Bluetooth or WiFi module — and backed up by an Arduino Uno, an L298 motor controller, and two geared DC motors powering the wheels.

Further taking advantage of the phone’s functionality, the robot is controlled by DTMF tones. Using the app DTMF Tone Generator and outputting through the 3.5mm jack, commands are interpreted by a MT8870DE DTMF decoder module.While this control method carries some risks — as with many IoT-like devices — [Kumar] has circumvented one of DTMF’s vulnerabilities by adding a PIN before the security car will accept any commands.

He obtains a live video feed from the phone using AirDroid in concert with VNC server, and assisted by a servo motor for the phone is enabled to sweep left and right for a better look. A VNC client on [Kumar]’s laptop is able to access the video feed and issue commands. Check it out in action after the break!

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Android Controlled Robot Extravaganza

August 4, 2012 by 3 Comments

We have no idea why, but since we featured Botiful, the Android-powered telepresence robot a few days ago, the tip line has been awash in robot/Android mashups. Here’s a few of the cool ones.

Using an Android as a remote control

[Stef] used a Samsung Galaxy S3 to control an old rc tank. The Android sends accelerometer and gyro data over Bluetooth to an Android where it powers a pair of H-bridges to turn the wheels.

Turning Android into a Robotic Operating System

ROS, or the Robot Operating System, provides a bunch of utilities for any type of robot such as point-cloud mapping to multi-joint arm control. [Lentin] sent in a guide on installing ROS on Android. So far, he can get accelerometer data, stills from the on-board camera, have the robot speak and use the small vibrator motor. Here’s a (somewhat limited) demo of [Lentin] playing with ROS in a terminal.

“Just a quick procrastination project”

Last May, [Josh] wrote in asking if a tread-based robot controlled through Skype would be a cool idea. We said ‘hell yeah’ and [Josh] scurried off to his workshop for a few months. He’s back with his tank-based robot. One really interesting bit is the robot responds to DTMF tones, allowing it to be controlled through Skype without any additional hardware. That’s damn clever. You can see a video of the SkypeRobot after the break.

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