Gesture-Controlled Robot Arm Is A Nifty Educational Build

Traditionally, robot arms have been controlled either by joysticks, buttons, or very carefully programmed routines. However, for [Narongporn Laosrisin’s] homebrew build, they decided to go with gesture control instead.

The MeArm robotic arm is built using laser cut acrylic parts, and can be had in a kit if so desired. It features four servo motors, charged with rotating the arm’s base, pushing the arm forwards and backwards, up and down, and actuating its gripper. The servos are under the command of a micro:bit microcontroller board, which itself receives signals from a second micro:bit which is strapped to the human wishing to control the arm. The second micro:bit detects gestures with its accelerometer, and then sends the relevant commands to the robotic arm’s micro:bit over its built-in radio link. The arm controller then commands the servos to execute the maneuver.

It may be a small robotic arm that doesn’t have the capacity to lift much, but that’s not the point. This project is a great way to teach students how to program microcontrollers, work with sensor inputs, and just generally how to solve engineering puzzles. To that end, it looks like [Narongporn] has a great project on hand for teaching their students. Video after the break.

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3D printed Hagrid's lantern with a magic wand

Micro:bit Brings 3D Printed Magic Lanterns To Life

[Elenavercher] loves engaging her primary school students, inspiring their imagination as well as teaching them the design thinking process. She has found that the very accessible rapid prototyping culture of 3D printing, micro:bit, and the like are perfect for teaching her students problem-solving and teamwork, and is always coming up with new lessons that will catch their attention. That brings us to her latest design, an interactive lantern and wand, which you could say is of the wizarding variety.

The lantern and the wand each have an integrated micro:bit serving as their brains. When the user shakes the wand, releasing a spell, the micro:bit in the wand, sends a user-defined number to the micro:bit in the lantern. The lantern has NeoPixels built-in, which then turn on, illuminating the lantern. When the user presses a button on the micro:bit instead of shaking it, the wand sends a signal to the lantern that tells it to “turn off.” Pretty simple, right?

The design itself is something any seasoned hacker could recreate; however, the magic in this build is how [Elenavercher] beautifully engages her elementary-aged students in the engineering design process. She starts off by encouraging her students to prototype the lantern and wand using paper which is a very inexpensive way to help them visualize the final product before investing too much time into the 3D design, a critical engineering design step — prototype fast and cheap with whatever you have on hand.

She then helps them design the lantern and wand in Tinkercad, a very beginner-friendly, yet increasingly capable CAD program. We really appreciate her detailed steps for the design as well as for navigating Tinkercad, both of which will help teach any tiny tikes in your life how to recreate the design. What’s really handy about Tinkercad is you can do mechanical CAD as well as write code for the micro:bit all within the same program. But [Elenavercher] also provides the final .hex file if you’d rather just get the build up and running.

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BBC Micro:Bit As Handheld Synthesizer

The BBC Micro:bit, while not quite as popular in our community as other microcontroller development boards, has a few quirks that can make it a much more interesting piece of hardware to build a project around than an Arduino. [Turi] took note of these unique features and decided that it was the perfect platform to build a synthesizer on.

The Micro:bit includes two important elements that make this project work: the LED matrix and a gyro sensor. [Turi] built a 5×5 button matrix for inputs and paired each to one of the diodes, which eliminates the problem of false inputs. The gyro sensor is used for detuning, which varies the pitch of any generated sound by a set amount according to the orientation of the device. It also includes a passive low-pass filter to make the sound more pleasant to the ear, especially for younger players of the machine. He’s released the source code on his GitHub page for anyone interested in recreating it.

While this was a one-off project for [Turi], he notes that using MicroPython to program it instead of C led to a lot of unnecessary complications, and the greater control allowed by C would enable some extra features with less hassle. Still, it’s a fun project that really showcases the unique features of this board, much like this tiny Sumo robot we covered over the summer.

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The Warm Glow Of A Luminous Clock

It seems there will never be an end to the number of ways to show the time. The latest is the LumiClock from [UK4dshouse], and it uses the seldom-seen approach of a sheet of luminous paper excited by a strip of UV LEDs that pass over it guided by a lead screw.

At its heart is a micro:bit, which generates the time in dot-matrix digital form as the LEDs are moved across the sheet. It in turn has a real-time-clock module to keep it on time, and it drives a little DC motor via a robotics driver board. The appearance of the whole devices is similar to an X-Y plotter without the Y axis, as a 3D-printed carrier is moved by the lead screw and slides along a pair of stainless steel tubes. The result is an unusual and eye-catching timepiece, whose retro dot-matrix numerals fade away and are refreshed with the new time.

We’ve had a bit of a play ourselves with UV luminous materials, and we can confirm they make an interesting alternative to some other display ideas in dimmer environments. This isn’t the first such clock we’ve shown you.

This robot costume is really robotic!

Really Robotic Robot Costume Will Probably Win The Contest

Still don’t have anything to wear to that Halloween party this weekend? Or worse, your kid hasn’t decided on a costume that you both can agree on? Well, look no further than [Natasha Dzurny]’s Sally Servo the Really Robotic Robot Costume and accompanying multi-part build guide. You might want to start by raiding that recycle bin for cardboard, because you’re going to need a lot of it.

This realistic robot costume even has a sound-reactive mouth.What you won’t need a lot of is hard-to-source parts, at least if you build it the [Natasha] and Brown Dog Gadgets way. Even so, there are a ton of cool moving and blinking bits and bobs to be made with servos, LEDs, and RGB LEDs connected up to something kid-friendly like the Micro:bit and the Brown Dog Gadgets Bit Board — that’s a base for the :bit that lets users connect components via LEGO and conductive tape.

Between Sally’s robotic googly eyes and her light-up belt, there are plenty of ideas here to steal and make your own, and each one is packaged in a great-looking guide complete with paper printing templates.

Our favorite part has to be the infinity mirror heart, which appears to be beating thanks to clever programming. That, and the costume details, like the waist-area wires running between the upper and lower pieces.

Is the party at your house? There’s probably still enough time to put together a projector-based stomping game for the driveway.

A tiny robot with two wheels for sumo tournaments

Pint-sized Sumo Robot Is Adorable, Accessible And Totally Awesome

We’ve seen plenty of impressive robots of all sizes here at Hackaday, but recently we were particularly inspired by [Hans Jørgen Grimstad] and his thrifty mini sumo build.

Using the BBC micro:bit platform as a starting point, Hans seized the opportunity to build a competitive mini sumo bot without breaking the bank. According to his blog, the enchanting little machine uses commonly available parts and cost around $30 when built in 2020 (or $50 according to the more recent video, perhaps taking into account the cost of hardware in these trying times).

The results can be seen in the video below. Some sacrifices were made – Hans admits that the 3.3 V linear regulator gets a little toasty, but the design is kept much simpler by doing away with a switching regulator. The 700 RPM N20 motors are wired directly up to the 6 V battery pack, giving this plucky wrestler plenty of sumo-smashing power.

Hans hopes that the build can lower barriers to entry for new builders in robot tournaments, being something that can easily be put together in a garage or local makerspace for a low, low price. The mini sumo form factor is a great beginner or amateur project, made even easier when makers like Hans put all the nitty-gritty details up on GitHub. This is certainly not the first accessible sumo robotics project that we have covered, and it won’t be the last. We hope we see loads more of these endearing robotic gladiators at future events.

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Totally Useless Coffee Dispenser Is Anything But

Good coffee is nice to have, sure, but frankly, caffeine is caffeine and we’ll take it any way we can get it. That includes freeze-dried, if that’s all you’ve got. We won’t judge anyone for their taste in caffeinated beverages, and to call this coffee dispenser ‘totally useless’ is just patently untrue. It clearly has a use, and even if you don’t like freeze-dried coffee, you could sacrifice one jar worth of Nescafe and fill it with Skittles or anything else that will fit in the little collector basket.

In this machine, the cup is the trigger — the 3D-printed plate underneath activates a micro switch embedded in the scrap wood base, and this triggers a micro:bit around back to actuate the stepper motor that twirls the collector basket around. Although [smogdog] has provided all the files, you’d have to come up with your own connector to suspend the thing over the cup and carve your own base.

We love it when we can see what a machine is doing, so not only is it useful, it’s beautiful. And it worked, at least for a little while. For some reason, it keeps burning out stepper motors. Check it out in proof-of-concept action after the break.

We’ve seen the Micro:bit do a lot, and this pinball machine is among the most fun.

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