[TBJ] is building what he calls a junkbox 3D printer. You can probably guess that he’s trying to salvage most of the parts for the device, and after pulling a stepper motor from an old printer he was in need of a way to control it. What he came up with is a stepper driver that uses discrete components that are easy to acquire and inexpensive. The design calls for two inputs, one that toggles the direction in which the motor will spin, and the other that triggers one step of the motor. A CD4013 dual flip-flop takes care of both of these inputs in one chip package.

The motor is driven by a pair of H-bridges that he built using six transistors each. The trick with a stepper motor is that you need to drive the four poles of the motor to a specific logic level at a specific time. For this [TBJ] uses a CD4017 decade counter. A network of diodes grounds half of the output lines based on the flip-flop that controls direction. Our friend the 555 timer provides a clock for the circuit, keeping everything moving at a predefined rate. Check out the video after the break for an explanation and demonstration.

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[Patrick McCabe] enjoys the challenge of playing chess against the computer but he wasn’t satisfied with the flat experience of on-screen gaming. No problem, he just built his own gantry-style chess robot that he can play against. Don’t be confused, he still doesn’t have to touch the pieces, but instead uses the dedicated control board seen on the left of the image above. The robotic arm that is mounted on a gantry takes care of moves for both players.

It’s a pretty normal CNC build, using four stepper motors to slide the moving bits along precision rod. An Arduino Mega drives the system, with a PC doing the heavy lifting using a program called My Robot Lab.

We certainly like it that [Patrick] spent a little bit of time making the cabinet and visible parts look nice. Chess is a civilized game and unfinished parts would be out-of-place. We didn’t see it in his writeup, but the one feature we’re really hoping he has implemented is the ability to have the robot automatically reset the board at the beginning of a game.

As you might have guess, you’ll find embedded video after the break.

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We get a lot of tips about old hardware playing recognizable tunes. But once in a while one of these projects goes above and beyond the others and this is a shining example of great hardware music. [FunToTheHead] put together a music video (embedded after the break) that shows his custom MIDI device playing Bach’s Toccata in d minor. He left some comments that clue us into the way he did it. Most obviously, he’s using the stepper motors from four floppy drives to create precisely pitched sounds. Internally, a PIC 18F14K50 acts as a MIDI-over-USB device, taking commands for all 128 MIDI notes as well as the pitch bends associated with them. The first four channels are played directly on each drive and the other twelve are triaged among the hardware by the microprocessor. But for the results heard in the video you’ll need to code your MIDI files by hand.

Bonus points to the video editor for the Phantom’s floppy-laden appearance in the video… it’s good to laugh!

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[Garagedeveloper] sent us his custom surveillance system, part 1, part 2, and part 3 after needing a way to find out why some cables at work were becoming unplugged (spoiler, the cleaners were messing up the wiring). At the base of the system is a web cam glued to a stepper motor. However, it gets much more in depth with a web front-end that allows the user to stream the feed and control the position of the stepper. We’re not particularly fond of how many different parts the project takes, while it all could be accomplished under C# with ASP.NET and parallel port library instead of including Arduino and excess code, but to each their own and the project turned out a success anyway.

[Jarek] found a non-functional robotic arm sitting around and wanted to get it working again. By adding a few custom boards to an Arduino he managed to do just that.

The arm is driven by six stepper motors, each having four control wires. To handle all of these [Jarek] used TIP120 transistors to protect the controller. This still leaves the problem of 24 control wires to connect. By using a couple of 74HC4514 demultiplex chips he cut that number down to just 8 Arduino control pins. He completed the project by interfacing an original Playstation controller as the input device.

Source code for the project is available for download but we didn’t see a schematic for his setup. This shouldn’t be a problem as the low parts count should mean the datasheets for the transistors and demultiplexers are all you really need.

[Audin] got a hold of a pressure gauge and decided to turn it into a clock. We were under the impression that these types of gauges were filled with oil but he didn’t detail cleaning it up for his purposes. Once he gained access to the guts he replaced them with a stepper motor. The motor connects to an Arduino with the help of a Darlington array for handling the large load. [Audin's] plans include using a real time clock (on order) and moving to an AVR ATmega8 microprocessor once the prototyping is finished. In the mean time, he has posted the code used in his current prototype.

Stay with us past the page break for some video of this in action. He’s got the needle dialed in for very precise movement and has coded a “jitter” effect as well. We’re not sure this would be the most convenient clock, but we’d love to affix it to our kitchen stove for a gnarly looking timer. [Audin] acquired the gauge at his local Habitat for Humanity ReStore, a place we’ve used many times to source reclaimed and unused items of all kinds for our projects.

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[Murray484] submitted his instructable on how to create a stepper motor controller from an old scanner. He removed the motor and controller from an old scanner then harvested the parts. He’s pretty much starting over, taking the ULN2003 chip from the scanner motor controller and putting it on a fresh board. He then wired it all up, installed the software and got it working. Finally, he built a container out of cardboard for it all. Though he could have made it nicer looking and used higher quality building materials, he was trying to make this a “green” project for the epilog laser cutter contest. He’s done a good job recycling, this could be pretty useful.

RepRap has released a new driver board for their stepper motors. They’ve honed the design to be easier to assemble and cheaper. We’re sure all of that is wonderful, but what really got our attention was the video. In the video, which you can see after the break, they run a test file through it to make it “sing” happy birthday. Is this something that everybody does and we’re just now catching on? Why all the musical stepper motors today?

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