Bluetooth stepper motor driver


[Dan] salvaged some parts from an old printer a while back and finally found some time to play with them. One of the things he was most interested in is the geared stepper motor seen above. He was able to get it running with an Arduino in no time so he decided to take the project a little bit further. What he ended up with is a stepper motor driver which can be controlled over Bluetooth.

The motor can’t be driven directly, but with a simple motor driver like the L293 chip [Dan] used it’s not hard to interface them with your control hardware of choice. From there he added an ATtiny85 which will take care of the stepping protocol necessary to move the motor. The Bluetooth module he’s using functions as a serial device, making it really simple to interface with the uC. [Dan] uses a pin header to connect the module, so switching to a different type of serial device in the future will be quick and painless.

After the break you can see him sending step commands to the driver board.

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Working 3D printed stepper motor

Stepper Small 1

Most 3D printers use stepper motors to control the movement of the extruder head. If you could actually print those motors it would be one more big step toward self-replicating hardware. Now obviously [Chris Hawkins'] working 3d printed stepper motor wasn’t built 100% through 3D printing, but the majority of the parts were. All that he had to add was the electronic driver pieces, magnets, wire, and a few nails.

The coils are made up of nails wrapped in magnet wire. The rotor is a 3D printed framework which accepts neodymium rare earth magnets. The axle is pointed which reduces the friction where it meets the cone-shaped support on either side of the frame. The IC on the upper right is a transistor array that facilitates switching the 20V driving the coils. The board on the lower right is a Digispark, which is an ATtiny85 breakout board that includes a USB edge connector for programming and a linear regulator which is how he gets away with feeding 20V as the source.

Don’t miss the demo video after the break where you can see the motor stepping 7.5 degrees at a time.

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CNC ping pong printer uses simple construction


This is one of the simplest CNC builds we’ve seen but it still functions quite well. It’s a clone of the EggBot, but is aimed at printing on spherical Ping Pong balls rather than oblong eggs. [Chad] calls it the Spherebot, but you should be careful not to confuse it with the morphing sphere robot which can walk around like a hexapod.

The project is both mechanically and electronically simple. The body of the printer is made up of three acrylic plates, which we’re sure were clamped together when drilling holes to guarantee proper alignment. Threaded rod and nuts are used to mount the plates to one another, as well as to hold the sphere in place while printing. One stepper motor turns the ball while the other pivots the pen mount. A servo motor is responsible for lifting the pen. The entire thing is driven by an Arduino along with two stepper motor driver boards. Don’t miss [Chad's] presentation embedded after the break.

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SCARA arm 3D printer


[Quentin Harley] must really have wanted to test his snuff when it comes to mechanical engineering. He’s been hard at work for a couple of years now designing his own SCARA arm 3D printer. That link leads to a recent summary article in which he shows off the build as seen above. It’s not fully functional yet, but he’s at the point where it’s time to develop the driver circuitry and firmware so he’s close. His blog is dedicated to this single project so click around and see what he went through along the journey.

The SCARA arm is seen in blue, using a couple of stepper motors to move the extruder mount along the x and y axes. The bed itself moves along the Z axis via two precision rods with a threaded rod in the center. As you can see, some of the parts are made of wood, and he used PVC for the cross supports between the upper and lower base platforms. But the majority of the build uses 3D printed parts, including the arms, drive gears, and mounting brackets.

[Thanks Peter]

Award clock put to good use as a bench meter


The motivation industry turns out these type of award trinkets by the millions. Here’s a way to actually put the thing to use. Instead of displaying time, the clock dial serves as the readout of a voltage meter.

When we first saw this post we assumed that the hack used some type of coil injection to drive the hands. But it turns out that this is mechanically driven. The image above shows the stepper motor which is mounted behind the clock. Its drive shaft is coupled with the adjustment knob on the back of the clock. The precision of the motor lets the PICAXE set the clock dial based on the number of motor steps. The hour hand shows the tens value with the minutes serving as ones (base 10, not base 60). This means the top measurable voltage is 12V — when the hour hand is at 12 the measurement is 0 volts plus tenths of a volt from the minute hand. With the dial taken care of the rest of the project focuses on measuring the voltage using the ADC, which has an upper limit of just 5V. This is overcome with a simple voltage divider.

After the break you can see the accuracy of the rig as it performs measurements next to a digital voltmeter.

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Custom gauges with a stepper motor breakout board


Throw some blinking LEDs on a project and it’s bound to make the front page of Hackaday. We do love builds of a more analog character, though, and this analog gauge stepper motor breakout board seems like just the ticket to make those projects a reality.

The idea behind the project is simple: take a stepper motor, put a needle on it, and connect it to an Arduino. Instant analog gauge, measuring anything an Arduino can calculate.

The motor used in the build is a Switec X27.168, the same motor used in the dashboard of tens of thousands of automobiles from dozens of different makes and models. Controlling the motors is done through [Guy Carpenter]‘s Switec X25 library for the Arduino, allowing an Arduino Uno to control up to three stepper motor gauges simultaneously.

The movement of the needle is amazingly smooth and quite fast, as seen in the video after the break. A pretty cool piece of kit if you want a more analog display than LEDs and LCDs can provide.

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Versatile motion dolly for time lapse photography


This beautiful build is a motion dolly for making time-lapse videos. It is at a point where you could consider it complete. After all, the segments featured in the video after the break look marvelous. But [Scottpotamas] has a few additions planned and it sounds like it won’t belong before he accomplishes his goals.

The build is a linear rail on which the camera rides. In the image above you can see the stepper motor which moves the camera mounted at the far end of the rig. This is controlled by an Arduino. Currently the camera is responsible for timing the capture of the images, but [Scottpotamas] says the firmware is nearly ready to hand this responsiblity over to the Arduino. The system is modular, with a simple setting for the length of the track. This way he can swap out for a longer or shorter rail which only takes about five minutes. He also included support for a panning mount for the camera. It allows the control box can be programmed to keep the subject centered in the frame as the camera slides along the track.

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