[Kevin Darrah] put together a good video showing how to control a stepper motor with, not a motor driver, but our fingers. Taking the really low-level approach to do this sort of thing gave us a much better understanding about the features of our stepper driver chips. Such as, for example, why a half step needed twice the current to operate.
[Kevin] starts with the standard explanation of coils, transistors, and magnets that every stepper tutorial does. When he hooks up simple breadboard with passives and buttons, and then begins to activate the switches in sequence is when we had our, “oh,” moment. At first even he has trouble remembering the correct sequence, but the stepper control became intuitive when laid out with tactile switches.
We set-up our own experiment to see if we remembered our lessons on the subject. It was a fun way to review what we already knew, and we learned some more along the way. Video after the break.
Continue reading “Get Really Basic With Steppers and Eight Buttons”
[HomoFaciens] is back at the bench again and working on improvements to his cheap and simple CNC machine.
The video below will no doubt remind you about previous versions of [HomoFaciens]’ CNC builds, which we’ve covered in depth. With an eye to spending as little as possible on his builds, most parts are recovered from e-waste, with a fair amount of Dumpster diving thrown in. For this upgrade, the salvaged brushed DC motors with their signature gap-toothed encoder disks are replaced with genuine bipolar steppers. The primary intention of his build is to learn (and teach) as much as possible, so he spends a good amount of time going over steppers and their control – how to determine phase wiring, how to wire up the not-salvaged-but-still-cheap drivers, directional control, and half-stepping. The mechanics are decidedly dodgy, but there are clever expedients aplenty – we especially like the oil cup fabricated from a brass tube and a bolt with a hole drilled in it. Everything just works, and the results to expense ratio is hard to beat.
While we appreciate the upgrades here, we’re still keen to see how junky his other trash can CNC can get. And we’re still waiting on the paper clip and cardboard challenge.
Continue reading “Trash Can CNC Gets a Stepper Upgrade”
When your passion is a sport that depends on Mother Nature’s cooperation, you need to keep a close eye on weather conditions. With this in mind, and not one to let work distract him from an opportunity to play, [mechanicalsquid] decided to build a wind-monitoring gauge with an old-school look to let him know when the wind is right for kitesurfing.
Being an aficionado of big engineering helped [mechanicalsquid] come up with a style for his gauge – big old dials and meters. We hesitate to apply the “steampunk” label to every project that retasks old technology, but it sure looks like a couple of the gauges he used could have been for steam, so the moniker probably fits here. Weather data for favorite kitesurfing and windsurfing locales is scraped from the web and applied to the gauges to indicates wind speed and direction. [mechanicalsquid] made a valiant effort to drive the voltmeter coil directly from the Raspberry Pi, but it was not to be. Servos proved inaccurate, so steppers do the job of moving the needles on both gauges. Check out the nicely detailed build log for this one, too.
For more weather station fun be sure to check out this meter-based weather station with a slightly more modern look. And for another build in the steampunk style, this vintage meter and Nixie power display is sure to impress.
Ham radio operators are curious beasts. They’ll go to great lengths to make that critical contact, and making sure their directional antennas are pointing the right way can be a big part of punching through. Of course there are commercial antenna rotators out there, but hams also like to build their own gear, like this Raspberry Pi-controlled 2-axis rotator.
[wilho]’s main motivation for this build seems to have been the sad state of the art in commercial 2-axis rotators, which seems firmly mired in the 90s. Eschewing the analog pot sensors on DC brushed motors that seem to dominate the COTS market, [wilho] went with steppers and stout gearboxes for the moving gear. Feedback on the axes comes from 10-bit absolute encoders, and an MPU9250 9-axis IMU makes sure he knows exactly where the antenna is pointing with respect to both compass heading and elevation. A mast-mounted Rasp Pi controls everything and talks through a REST API to custom software that can return the antenna to custom set-points or track the moon, satellites, or the ISS. It’s a very impressive bit of kit that’s sure to drive your home-owners association bonkers.
For another 2-axis antenna positioner, check out 2015 Hackaday Prize finalist SATNOGS.
Continue reading “Track Satellites with a 2-axis Antenna Positioner”
[Rohit Gupta] is back with a plotter made from scrap CD drives and an old RC servo. [Rohit] is working on hacks to create CNC machines and sharing his activities with the world. His CNC design calls for salvaged stepper motors so he first built a device for testing them. You’ve got to admire his use of the language. He named his plotter project ‘Sketchy’ and his motor tester is called ‘Easy Peasy’.
After finding some CD drives at the scrap pile he tore them down to test with Easy Peasy. The raw materials for the frame came from a wooden crate for an AC unit but he didn’t just start cutting it up. Nope, first he created plans with CAD; now that’s a hack you have to admire.
With the steppers tested working, and the base build under way he moved onto the control system. Originally the hardware was demonstrated using an MSP430. This worked, but a flaw in the hardware design was found. With the pen attached directly to the servo horn, it would draw a long line when being rotated away from the drawing position.
The fix is a replacement servo setup which lifts the pen up instead of rotating it. But that showed that the drawing surface wasn’t smooth. The pen kept missing places or getting caught and destroyed. The use of a spring loaded pen solved this issue. Success!
One further change migrated away from the MSP430 in favor of an Arduino Pro Mini in order to use a GRBL library instead of the g-code generator which was performing questionably. Since he likes Hackaday so much one of his first attempts with the final version of Sketchy was our logo, shown in the video after the break.
When we last saw [Rohit] he had created a fancy PCB ruler to measure components.
Continue reading “A Wooden Based, CD Stepper Scribbler”
You know how it goes – sometimes you look at your social calendar and realize that you need to throw together a quick claw machine. Such was the dilemma that [Bob Johnson] found himself in during the run-up to the Nashville Mini Maker Faire, and he came up with a nice design that looks like fun for the faire-goers.
Seeking to both entertain and enlighten the crowd while providing them with sweet, sweet candy, [Bob] was able to quickly knock together a claw machine using mainly parts he had on hand in the shop. The cabinet is nicely designed for game play and to show off the gantry mechanism, which uses aluminum angle profiles and skate bearings as custom linear slides. Plenty of 3D printed parts found their way into the build, from pillow blocks and brackets for the stepper motors to the servo-driven claw mechanism. A nice control panel and some color-coded LED lighting adds some zip to the look, and a Teensy LC runs the whole thing.
Like [Bob]’s game, claw machines that make it to Hackaday seem to be special occasion builds, like this claw machine built for a kid’s birthday party. Occasion or not, though, we think that fun builds like these bring the party with them.
Continue reading “Full Size Custom Claw Machine Built with Parts on Hand”
Few hackers have trouble understanding basic electric motors. We’ve all taken apart something that has a permanent magnet DC motor in it and hooked up its two leads to a battery to make it spin. Reverse the polarity, reverse the spin; remove the power, stop the spin. Stepper motors (and their close cousins, brushless DC motors) are a little tougher to grok, though, especially for the beginner. But with a giant 3D printed stepper motor, [Proto G] has made getting your head around electronically commutated motors a little easier.
While we’ve seen 3D printed stepper motors before, the size and simple layout of this one really lends to understanding the theory. With a 3D-printed frame, coils wound on nails, and rare-earth magnets glued to a rotor, this is an approachable build that lays the internals of a stepper motor out for all to see and understand. You can easily watch how the rotor lines up as the various coils are energized in a circular pattern, although it might be more revealing to include bi-color LEDs to indicate which coils are energized and what the polarity is. Those would be especially helpful demonstrating the concept of half-stepping. We’d also like to see more detail on the controller electronics, although admittedly all the video-worthy action is in the motor itself.
Continue reading “Giant Stepper Motor Gets You Up to Speed on Theory”