2022 Sci-Fi Contest: A Hand-Following Robot, Powered By Arduino

April 13, 2022 by Lewin Day No comments

If there’s one thing audiences love in sci-fi, it’s a cute robot companion that follows the heroes around. If you want one of your own, starting with this build from [mircemk] could be just the ticket.

The build relies on the classic Arduino Uno microcontroller, which talks to a HC-SR04 ultrasonic sensor module and two infrared sensors in order to track a human target and follow it around. Drive is thanks to four DC gear motors, driven by a L293D motor driver, with a two-cell lithium battery providing power for everything onboard.

The robot works in a simple manner, following a hand placed in front of the robot’s sensors. First, the robot checks for the presence of an object in front using the ultrasonic sensor. If something is detected, the twin infrared sensors mounted left and right are used to guide the robot, following the hand.

It’s not a sophisticated algorithm, and it won’t really let your robot follow you down a crowded street. However, it’s a great project to learn on for beginners and could serve as a great entry into more advanced projects using face tracking or other techniques. Video after the break. Continue reading “2022 Sci-Fi Contest: A Hand-Following Robot, Powered By Arduino” →

Raspberry Pi Creates Melody

March 28, 2022 by Bryan Cockfield 2 Comments

For those who are not into prog rock in the 70s or old radio shows from the 40s, the Theremin may be an unfamiliar musical instrument. As a purely electronic device, it’s well outside the realm of conventional musical instruments. Two radio antennas detect the position of the musician’s hands to make a unique sound traditionally associated with eeriness or science fiction.

Normally a set of filters and amplifiers are used to build this instrument but this build instead replaces almost everything with a Raspberry Pi Zero 2, and instead of radio antennas to detect the position of the musician’s hands a set of two HC-SR04 distance sensors are used instead. With the processing power available from the Pi, the modernized instrument is able to output MIDI as well which makes this instrument easily able to interface with programs like GarageBand or any other MIDI-capable software.

The project build is split into two videos, the second of which is linked below. The project code is also available on the project’s GitHub page, so anyone with the Pi and other equipment available can easily start experimenting with this esoteric and often overlooked musical instrument. It’s been around for over 100 years now, and its offshoots (including this build) are as varied as the sounds they can produce.

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Human-Following Utility Trailer

July 12, 2021 by Chris Lott 27 Comments

[Théo Gautier] thought that a human-following utility trailer would be helpful for people working on farms. He didn’t just think about it, however, he designed and built it as a final project at the Agrilab FabAcademy at the University UniLasalle Polytechnique in northern France. He took the idea from concept to fruition in six weeks.

His build log documents the project very well, and takes you through his design choices and their implementation. The brains of the cart are a SAMD21E board that he made himself, and its sensory perception of the world is provided by HC-SR04 ultrasonic sensors and a PixyCam 2. Locomotion is provided by four each 100W DC motor / gearbox assemblies. He’s put a lot of effort into the construction process and posted a lot of photos of the intermediate steps. One piece of advice that caught our eye was to measure the diagonals of your frame repeatedly when welding it together — things can and do shift around. If you don’t, you may have to rectify the mistake like [Théo] did, with a big hammer.

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Facing The Coronavirus

August 22, 2020 by Brian McEvoy 1 Comment

Some of us are oblivious to how often we touch our faces. The current finding is we reach for our eyes, nose, or mouth every three to four minutes. Twenty times per hour is an awful lot of poking, picking, itching, and prodding when we’re supposed to keep our hands away from glands that can transmit and receive disease. To curb this habit and enter the 2020 Hackaday Prize, [Lloyd lobo] built a proof-of-concept device that sounds the alarm when you reach for your face.

We see an Arduino Uno connected to the classic HC-SR04 ultrasonic distance sensor, an LED, and we have to assume a USB battery pack. [Lloyd] recommends the smaller Nano, we might reach for the postage-stamp models and swap the ultrasonic module out for the much smaller laser time of flight sensor. At its soul, this is an intruder alarm. Instead of keeping siblings out of your room, you will be keeping your hands out of the area below the bill of the hat where the sensor is mounted. If you regularly lift a coffee cup to your lips, it might chastise you, and if you chew sunflower seeds, you might establish a tempo. *crunch* *chip* *beep* *crunch* *chip* *beep*

We have reviewed technology to improve our habits like a bracelet that keeps a tally, and maybe there is a book that will help shirk some suboptimal behaviors.

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Miles The Spider Robot

August 6, 2020 by Orlando Hoilett 7 Comments

Who doesn’t love robotic spiders? Today’s biomimetic robot comes in the form of Miles, the quadruped spider robot from [_Robox].

Miles uses twelve servos to control its motion, three on each of its legs, and also includes a standard HC-SR04 ultrasonic distance sensor for some obstacle avoidance capabilities. Twelve servos can use quite a bit of power, so [_Robox_] had to power Miles with six LM7805 ICs to get sufficient current. [_Robox_] laser cut acrylic sheets for Miles’s body but mentions that 3D printing would work as well.

Miles uses inverse kinematics to get around, which we’ve seen in a previous project and is a pretty popular technique for controlling robotic motion. The Instructable is a little light on the details, but the source code is something to take a look at. In addition to simply moving around [_Robox_] developed code to make Miles dance, wave, and take a bow. That’s sure to be a hit at your next virtual show-and-tell.

By now you’re saying “wait, spiders have eight legs”, and of course you’re right. But that’s an awful lot of servos. Anyway, if you’d rather 3D print your four-legged spider, we have a suggestion.

DIY Baby MIT Cheetah Robot

July 5, 2020 by Orlando Hoilett 7 Comments

3D printers have become a staple in most makerspaces these days, enabling hackers to rapidly produce simple mechanical prototypes without the need for a dedicated machine shop. We’ve seen many creative 3D designs here on Hackaday and [jegatheesan.soundarapandian’s] Baby MIT Cheetah Robot is no exception. You’ve undoubtedly seen MIT’s cheetah robot. Well, [jegatheesan’s] hack takes a personal spin on the cheetah robot and his results are pretty cool.

The body of the robot is 3D printed making it easy to customize the design and replace broken parts as you go. The legs are designed in a five-bar linkage with two servo motors controlling each of the four legs. An additional servo motor is used to rotate an HC-SR04, a popular ultrasonic distance sensor, used in the autonomous mode’s obstacle avoidance mechanism. The robot can also be controlled over Bluetooth using an app [jegatheesan] developed in MIT App Inventor.

Overall, the mechanics could use a bit of work — [jegatheesan’s] baby cheetah probably won’t outpace MIT’s robot any time soon — but it’s a cool hack and we’re looking forward to a version 3. Maybe the cheetah would make a cool companion bot?

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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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