Mag Loop Antenna Has A Brain

April 11, 2023 by Al Williams 26 Comments

Magnetic loop antennas are great if you are limited on space since they are just a potentially small loop of wire. The problem is, they are sharply tuned. You normally have an adjustment capacitor to tune the antenna to different frequencies. [TekMakerUK] built one with a motor and an Arduino that he can tune from an Android phone. You can see more about the project in the video below.

If you want to transmit, the capacitor is often the weak part of the system. Luckily, some old gear yielded a capacitor with multiple sections and enough plate distance to handle the 5W desired. Of course, motor driving a capacitor isn’t a new idea, but this setup is nice since it uses a stepper motor and a rotary encoder.

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A white, house-shaped clock with the words "TEMPUS NECTIT" written in faux Roman script in black on a strip of silver at the base of the "roof." a white power cord extends from the left of the enclosure, and the center of the clock is a 22 pin knitting machine wheel with one pin covered in silver metalic. A white plastic peg extends from the bottom right of the enclosure to hold the feedstock yarn.

Tempus Nectit, A DIY Knitting Clock With Instructions

April 5, 2023 by Navarre Bartz 1 Comment

We’re no strangers to unusual clocks here at Hackaday, and some of our favorites make time a little more tangible like [Kyle Rankin]’s knitting clock.

Inspired by our coverage of [Siren Elise Wilhelmsen]’s knitting clock, [Rankin] decided to build one of his own. Since details on the build from the original artist were sparse, he had to reverse engineer how the device worked. He identified that a knitting clock is essentially a knitting machine with a stepper motor replacing the hand crank.

Using a Raspberry Pi with an Adafruit motor hat connected to a stepper motor and a 3D printed motor adapter, [Rankin] was able to drive the knitting machine to do a complete round of knitting every twelve hours. By marking one of the knitting pegs as an hour hand, the clock works as a traditional clock in addition to its year-long knitting task. [Rankin] says he still has some fine tuning to work on, but that he’s happy to have had the chance to combine so many of his interests into a single project.

If you’re looking for more knitting hacks, check out this knitted keyboard instrument or a knitted circuit board.

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Stepper Killer Killer Killed, Repair Attempted

March 8, 2023 by Chris Lott 12 Comments

The low-cost servo motor in [Clough42]’s lathe’s electronic leadscrew bit the dust recently, and he did a great job documenting his repair attempts ( see video below the break ). When starting the project a few years ago, he studied a variety of candidate motors, including a ClearPath servo motor from Teknic’s “Stepper Killer” family. While that motor was well suited, [Clough42] picked a significantly lower-cost servo motor from China which he dubbed the “Stepper Killer Killer”.

He does a very thorough post-mortem of the motor’s integrated servo controller, checking the circuits and connections on the interface PCB first. Not finding any obvious problem, he proceeds to the main PCB which contains the microcontroller, motor driver transistors, and power supplies. There is no visible damage, but a check of the logic power supply shows 1.65V where 3.3V is expected. Looking at the board with a smart-phone mounted IR camera, he quickly finds the bad news — the microcontroller has shorted out.

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3-DOF Robot Arm Wrist Without The Motor Weight

November 3, 2022 by Danie Conradie 15 Comments

A major challenge of robotic arms is the weight of the actuators, especially closer to the end of the arm. The long lever arm means more torque is required from the other actuators, and everything flexes a bit more. To get around this, [RoTechnic] moved the wrist stepper motors off the arms entirely.

He built a push-pull mechanism that uses braided fishing line to transfer motion to the robot arm’s wrist using Bowden tubes. The motors are mounted on the arm’s base, with a drum and two lengths of fishing line on the shafts. The lines pass through an adjustable tensioner before entering the Bowden tubes. This drum mechanism is also present on each of the three rotating axes of the wrist.

[RoTechnic] used an Arduino-powered RAMPS board as a controller, which is programmed to accept over the serial interface. He created a simple GUI and scripting interface in Jupyter Labs to generate and send command, which seems like an excellent solution for testing.

We can see this mechanism being a useful for a variety of motion applications, and definitely something to add to the idea toolbox. It is somewhat similar to some other cable-operated joints we’ve seen in humanoid robots and other 3D printed arms.

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Flux: A Forty Foot Long Kinetic Art Piece

October 7, 2022 by Dave Rowntree 5 Comments

No office space is complete without some eye-catching art piece to gawp at whilst you mull over your latest problem. But LED-based displays are common enough to be boring these days. Kinetic art pieces are where it’s at, and this piece called Flux is a perfect example.

Commissioned for the Toronto office of a very popular e-commerce platform and constructed by [Nicholas Stedman], Flux consists of twenty identical planks on the ceiling, arranged in a line forty feet long. Each plank has a pair of rotating prisms, constructed from a stack of foam sheets, finished with metallic paint. The prisms are spun by individual stepper motors, each of which is driven by a TMC2160-based module, making them whisper-quiet.

A simple 3D printed bracket holds a small PCB holding an AMS AS5600 rotary magnetic encoder, onto the rear of the stepper motor. This allows for closed-loop feedback to the shared Arduino, which is very important for a sculpture such as this. Each Arduino is hooked up to a Raspberry Pi, running a simple application written in node.js which is responsible for coordinating movement, as well as uploading updated firmware images as required. A simple, but very effective build, we think!

Even more fun are kinetic art installations that are reactive to some data source, such as Adad, which visualizes lightning strike data. If these builds are just too big and complex, we’ve seen many examples of smaller desktop toys, such as this 3D printed tumbling chain demo for example.

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Ethersweep: An Easy-To-Deploy Ethernet Connected Stepper Controller

September 7, 2022 by Dave Rowntree 35 Comments

[Neumi] over on Hackaday.IO wanted a simple-to-use way to drive stepper motors, which could be quickly deployed in a wide variety of applications yet to be determined. The solution is named Ethersweep, and is a small PCB stack that sits on the rear of the common NEMA17-format stepper motor. The only physical connectivity, beside the motor, are ethernet and a power supply via the user friendly XT30 connector. The system can be closed loop, with both an end-stop input as well as an on-board AMS AS5600 magnetic rotary encoder (which senses the rotating magnetic field on the rear side of the motor assembly – clever!) giving the necessary feedback. Leveraging the Trinamic TMC2208 stepper motor driver gives Ethersweep silky smooth and quiet motor control, which could be very important for some applications. A rear-facing OLED display shows some useful debug information as well as the all important IP address that was assigned to the unit.

Control is performed with the ubiquitous ATMega328 microcontroller, with the Arduino software stack deployed, making uploading firmware a breeze. To that end, a USB port is also provided, hooked up to the uC with the cheap CP2102 USB bridge chip as per most Arduino-like designs. The thing that makes this build a little unusual is the ethernet port. The hardware side of things is taken care of with the Wiznet W5500 ethernet chip, which implements the MAC and PHY in a single device, needing only a few passives and a magjack to operate. The chip also handles the whole TCP/IP stack internally, so only needs an external SPI interface to talk to the host device.

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Cute NFL Standings Tracker Uses Little Mini Helmets

August 18, 2022 by Lewin Day 20 Comments

If you’re a die-hard sports fan, there’s nothing you love more than staying abreast of developments in the league, from top to bottom. [Kiu] had a family member that was big into NFL, so set about building them a remarkably cool ladder tracker.

The tracker displays the NFL league table with a ten-minute delay, thanks to a paid live data feed from MySportsFeeds.com. When an update comes in, miniature helmets representing each team in the competition are moved into the correct order. The helmets sit on little plastic tags that make moving them easy, reliable, and repeatable. Built using parts familiar to the 3D printer world, this tracker relies on steppers and V-rails for linear movement, under the command of an Arduino Nano.

It’s a build that would look great in any games room, and we bet a scaled-up version would look the business in an upmarket sports bar. Let’s be honest – the league’s top quarterbacks will all be fighting to have one of these sooner rather than later. That’s not to say it won’t sting to come home to your team’s helmet scooting down the board after a painful loss!

We’ve seen some other interesting sports tracking projects over the years, too. Video after the break!
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