Juggling Machine Listens To The Bounce To Keep Ball In The Air

July 25, 2018 by Dan Maloney 10 Comments

It’s a seemingly simple task: bounce a ping-pong ball on a wooden paddle. So simple that almost anyone can pick up a ball and a paddle and make a reasonable job of it. Now, close your eyes and try to do it just by the sound the ball makes when it hits the paddle. That’s a little tougher, but this stepper-driven platform juggler manages it with aplomb.

That’s not to say that the path to the finished product in the video below was a smooth one for [tkuhn]. He went through multiple iterations over the last two years, including a version that surrounded the juggling platform with a fence of phototransistors to track where the ball was at any time. That drove four stepper motors through a cross-linkage that popped the platform up at just the right moment to keep the ball moving, and at just the right angle to nudge it back toward the center of the platform. The current version of the platform does away with the optical sensors in favor of four small microphones. The mics pick up the sharp, well-defined sound of the ball hitting the platform, process the signal through an analog circuit, and use that signal to trigger a flip-flop if the signal exceeds a setpoint. An Arduino then measures the time delay between arriving signals, calculates the ball’s position on the platform, and drives the steppers through a PID loop to issue the corrective bounce.

The video below is entrancing, but we found ourselves wishing for a side view of the action too. It’s an impressive build nonetheless, one that reminds us of the many maze-runner and Stewart platform robots we’ve seen.

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An Integrated Electromagnetic Lifting Module For Robots

July 25, 2018 by Donald Papp 7 Comments

The usual way a robot moves an object is by grabbing it with a gripper or using suction, but [Mile] believes that electromagnets offer a lot of advantages that are worth exploring, and has designed the ELM (Electromagnetic Lifting Module) in order to make experimenting with electromagnetic effectors more accessible. The ELM is much more than just a breakout board for an electromagnet; [Mile] has put a lot of work into making a module that is easy to interface with and use. ELM integrates a proximity sensor, power management, and LED lighting as well as 3D models for vertical or horizontal mounting. Early tests show that 220 mW are required to lift a 1 kg load, but it may be possible to manage power more efficiently by dynamically adjusting drive voltage depending on the actual load.

[Mile]’s focus on creating an easy to use, integrated solution that can be implemented easily by others is wonderful to see, and makes the ELM a great entry for The Hackaday Prize.

Was The Self Driving Car Invented In The 1980s?

July 25, 2018 by Al Williams 29 Comments

The news is full of self-driving cars and while there is some bad news, most of it is pretty positive. It seems a foregone conclusion that it is just a matter of time before calling for an Uber doesn’t involve another person. But according to a recent article, [Ernst Dickmanns] — a German aerospace engineer — built three autonomous vehicles starting in 1986 and culminating with on-the-road demonstrations in 1994 for Daimler.

It is hard to imagine what had to take place to get a self-driving car in 1986. The article asserts that you need computer analysis of video at 10 frames a second minimum. In the 1980s doing a single frame in 10 minutes was considered an accomplishment. [Dickmanns’] vehicles borrowed tricks from how humans drive. They focused on a small area at any one moment and tried to ignore things that were not relevant.

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Bananas Against Racism

July 20, 2018 by Brian McEvoy 42 Comments

This is a tale as old as time. Not love, it is about keeping something you made safe from those who would destroy something beautiful. In this case, the thing of beauty is a talking banana who reads Twitch and Youtube comments. The ne’er-do-wells are trolls seeking to ban-anana the account by forcing it to recite restricted words.

The problems stem from a visit from [Greekgodx], whose followers tend toward the dark side. When they set their sights on [Mike Nichols]’ yellow automaton, things slipped into a bleak place, and a twenty-four-hour ban falls on the fruit. A bunch of filtering is done, but it isn’t enough to stop the trolls, and the tally-man adds a second permanent strike against the account. An arms race of slurs and filtering ensued until the robot was able to reject all attempts at racism.

The banana has since been peeled from the feeds, but if silly robots are your cup of tea, check out [Simone Giertz] turning a car into a computer mouse.

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Dual Brushed Motor Controller Doesn’t Care How It Receives Commands

July 18, 2018 by Ben James 3 Comments

The simple DC brushed motor is at the heart of many a robotics project. For making little toy bots that zip around the house, you can’t beat the price and simplicity of a pair of brushed motors. They’re also easy to control; you could roll your own H-bridge out of discrete transistors, or pick up one of the commonly used ICs like the L298N or L9110S.

But what if you want an all-in-one solution? Something that will deliver enough current for most applications, drive dual motors, and deal with a wide range of input voltages. Most importantly, something that will talk to any kind of input source. For his Hackaday prize entry, [Praveen Kumar] is creating a dual brushed motor controller which can handle a multitude of input types. Whether you’re using an IR remote, a Pi communicating over I2C, an analog output or Bluetooth receiver, this driver can handle them all and will automatically select the correct input source.

The board has an ATmega328p brain, so Arduino compatibility is there for easy reprogramming if needed. The mounting holes and header locations are also positioned to allow easy stacking with a Pi, and there’s a status LED too. It’s a great module that could easily find a place in a lot of builds.

If you need even more control over your brushed motor, you can soup up its capabilities by adding a PID loop for extra smarts.

Emotional Hazards That Lurk Far From The Uncanny Valley

July 17, 2018 by Roger Cheng 14 Comments

A web search for “Uncanny Valley” will retrieve a lot of information about that discomfort we feel when an artificial creation is eerily lifelike. The syndrome tells us a lot about both human psychology and design challenges ahead. What about the opposite, when machines are clearly machines? Are we all clear? It turns out the answer is “No” as [Christine Sunu] explained at a Hackaday Los Angeles meetup. (Video also embedded below.)

When we build a robot, we know what’s inside the enclosure. But people who don’t know tend to extrapolate too much based only on the simple behavior they could see. As [Christine] says, people “anthropomorphize at the drop of the hat” projecting emotions onto machines and feeling emotions in return. This happens even when machines are deliberately designed to be utilitarian. iRobot was surprised how many Roomba owners gave their robot vacuum names and treated them as family members. A similar eruption of human empathy occurred with Boston Dynamics video footage demonstrating their robot staying upright despite being pushed around.

In the case of a Roomba, this kind of emotional power is relatively harmless. In the case of robots doing dangerous work in place of human beings, such attachment may hinder robots from doing the job they were designed for. And even more worrisome, the fact there’s a power means there’s a potential for abuse. To illustrate one such potential, [Christine] brought up the Amazon Echo. The cylindrical puck is clearly a machine and serves as a point-of-sale terminal, yet people have started treating Alexa as their trusted home advisor. If Amazon should start monetizing this trust, would users realize what’s happening? Would they care?

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Watney: A Fully 3D Printed Rover Platform

July 15, 2018 by Tom Nardi 9 Comments

We’re getting to the point that seeing 3D printed parts in a project or hack isn’t as exciting as it was just a few years ago. The proliferation of low-cost desktop 3D printers means that finding a printer to squirt out a few parts for your build isn’t the adventure it once was. Gone are the days of heading to a local hackerspace or college hoping their janky Mendel felt like working that day. But all that really means is that hackers and makers now have the ability to utilize 3D printing even more. Forget printing one or two parts of your design, just print the whole thing.

That’s exactly what [Nik Ivanov] did with Watney, his fully 3D printed rover project. After lamenting that many so-called 3D printed rovers were anything but, he set out to design one that was not only made primarily of printed parts, but was robust enough to put some real work in. Over the course of several design iterations, he built a very capable all-wheel drive platform that needs only some electronics and a handful of M3 screws to leap into action.

As long as you’ve got a 3D printer big enough to handle the roughly 120mm x 190mm dimensions of this bot’s body, you’re well on the way to owning your very own video rover. [Nik] recommends printing everything in PETG, no doubt for its increased strength when it comes to things like the drive gears. Plus it’s low warp, which is really going to help when printing the top and bottom sections of the body. TPU is advised for the tires, but if you don’t have any (or your printer chokes on flexible filaments) you can just wrap the wheels with wide rubber bands.

[Nik] is using a Raspberry Pi Zero W as the brains of the operation, but the beauty of an open platform like this is that you could easily swap out the controls for something else to meet your needs. In addition to the Pi, there’s a L298N H-bridge motor controller to interface with the dual geared motors, as well as a servo to provide tilt for the SainSmart camera module.

We’ve often been surprised at just how expensive commercial robotics platforms can be, so we’re keenly interested in seeing if the availability of designs like this spur on DIY rover development. Though if you’re looking for something a little more rough and tumble, we’ve seen a 3D printed rover that looks combat-ready.

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