An MSP430-based Automatic Fish Feeder

[Dmitri] wanted to buy an automatic feeding setup for his aquarium, but he found that most off-the-shelf feeders are really inaccurate with portion control. [Dmitri]’s fish is sensitive to overfeeding, so an off-the-shelf feeder wouldn’t get the job done. Since [Dmitri] knows a thing or two about electronics, he set out to build his own microcontroller-based automatic feeding machine.

[Dmitri]’s machine is based around a MSP430 that starts feeding at scheduled times and controls how much food is dispensed. The MSP lives on a custom PCB that [Dmitri] designed, which includes a stepper motor driver and input for an endstop sensor. The board is wired to a stepper motor that advances a small wooden board with a series of holes in it. Each hole is filled with a single serving of food. The board slides along a piece of U-channel, and food drops out of each hole into the aquarium when the hole reaches the end of the channel.

The whole build is very well documented, and [Dmitri] explains each block of his schematic in detail. His firmware is also open-source, so you can build your own fish feeder based off of his design. Check out the video after the break to see the feeder in action.

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3D-Printed Clock Tells Time with Gears

[ekaggrat] designed a 3d-printed clock that’s fairly simple to make and looks awesome. The clock features a series of 3d-printed gears, all driven by a single stepper motor that [ekaggrat] found in surplus.

The clock’s controller is based around an ATtiny2313 programmed with the Arduino IDE. The ATtiny controls a Darlington driver IC which is used to run the stepper motor. The ATtiny drives the stepper motor forward every minute, which moves both the hour and minute hands through the 3d-printed gears. The hour and minute are indicated by two orange posts inside the large gears.

[ekaggrat] etched his own PCB for the microcontroller and stepper driver, making the build nice and compact. If you want to build your own, [ekaggrat] posted all of his design files on GitHub. All you need is a PCB (or breadboard), a few components,  and a bit of time on a 3D printer to make your own clock.

Timelapse Photography on an Android-Powered Dolly

If you’re heading off on a trip to Alaska, you need to make sure you have plenty of supplies on hand for the wilderness that awaits. If you’re [Bryce], that supply list includes some interesting photography equipment, including a camera dolly that he made to take time-lapse video of the fantastic scenery.

On the hardware side, the dolly carries the camera on a rail that is set up on a slant. The camera starts on one side and moves up and towards the otherside which creates a unique effect in the time-lapse. The rig is driven by a stepper motor, and rides on some pretty fancy bearings. The two cameras [Bryce] plans to use are a Canon T2i and a EOS-M which sit on the top from a tripod.

The software and electronics side is interesting as well. Instead of the usual Arduino, [Bryce] opted for controlling the rig through Android and a IOIO board. This gives the project a lot of options for communications, including Bluetooth. The whole thing is powered by a 19V battery pack. If you’re looking for something a little simpler, you might want to check out the egg timer for time lapse! Check out the video of [Bryce]’s rig in action after the break.

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Sweet Stepper of [Jeremy]’s Rocks Out with its Box Out

Inspired by the floppy drive orchestras of others, [Jeremy] has built a Pi-driven MIDI music box with stepper motor resonators and outlined the build on

Control for the motors comes from an Iteaduino Mega 2560. The music starts as a MIDI file, gets processed into a text file, and is played over serial by a Raspberry Pi. He’s added percussion using K’NEX instruments and 9g servos, which we think is a nice touch. It can be powered via LiPo or from the wall, and [Jeremy] baked in protection against blowing up the battery. As he explains in the tour video after the break, the box is clamped to a wooden table to provide richer sound.

[Jeremy]’s favorite part of the build was enclosing the thing as it was his first time using panel-mount components. Stick around to see a walk-through of the guts and a second video demonstrating its musical prowess.

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Changing Unipolar Steppers To Bipolar


If you’ve been a good little hacker and have been tearing apart old printers like you’re supposed to, you’ve probably run across more than a few stepper motors. These motors come in a variety of flavors, from the four-wire deals you find in 3D printer builds, to motors with five or six wires. Unipolar motors – the ones with more than four wires – are easier to control, but are severely limited in generating torque. Luckily, you can use any unipolar motor as a more efficient bipolar motor with a simple xacto knife modification.

The extra wires in a unipolar motor are taps for each of the coils. Simply ignoring these wires and using the two coils independently makes the motor more efficient at generating torque.

[Jangeox] did a little experiment in taking a unipolar motor, cutting the trace to the coil taps, and measuring the before and after torque. The results are impressive: as a unipolar motor, the motor has about 380 gcm of torque. In bipolar mode, the same motor has 800 gcm of torque. You can check that video out below.

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Pulse Generator Tells Your Motors “Get Ta Steppin”

Stepper Motor Pulse Generator

Stepper motors are great for a bunch of projects; CNC machines, clocks or robots for example. Sometimes when working on a project that does include a stepper motor and driver, it would be nice to test that part of the build without hooking everything up. A pulse generator could be used to complete such a task and [CuteMinds] has put together a DIY friendly version tailored specifically for stepper motors. This device makes quick and easy work for testing out those stepper motors.

At the heart of the pulse generator is a 12F675 microchip which looks to the resistance value of a potentiometer to adjust the square wave step signal output from 20hz to 3khz. Just having the step signal would pretty cool but this project goes a little farther. There are 3 sets of headers on the board that allow you to connect either a jumper or switch in order to: 1) turn the power on, 2) enable the stepper driver and 3) select the direction the motor turns. The on-board batteries make this unit portable for remote usage.

If you are itching to make one for yourself, the Eagle schematic and board files are available for download at the above link.

Hackaday Links: June 8, 2014


Yes, dogfighting with RC planes is cool. You know what’s even cooler? RC jousting. Considering these eight foot long planes are probably made of foam board or Depron, they’ll probably hold up for a fairly long time. The perfect application of RC FPV.

Home automation is the next big thing, apparently, but it’s been around for much longer than iPhones and Bluetooth controllable outlets and smart thermostats. Here’s a home automation system from 1985. Monochrome CRT display panel (with an awesome infrared touch screen setup), a rat’s nest of wiring, and a floor plan drawn in ASCII characters. It’s also Y2K compliant.

Here’s an idea for mobile component storage: bags. Instead of tackle and tool boxes for moving resistors and other components around, [Darcy] is using custom bags made from polyethylene sheets, folded and sealed with an impulse sealer. It’s not ESD safe, but accidentally zapping a LED with an ESD would be impressive.

Need a stepper motor test circuit? Easy, just grab one of those Polulu motor drivers, an ATtiny85, wire it up, and you’re done. Of course then you’re troubled with people on the Internet saying you could have done it with a 555 timer. This one is for them. It’s a 555, some wire, and some solder. Could have done it with discrete transistors, though.

Someone figured out Lego Minifigs can hold iDevice charge cables. +1 for the 1980s spaceman.

Remember that “electronic, color sensing, multicolor pen” idea that went around the Internet a year or so ago? It’s soon to be a Kickstarter, and man, is this thing full of fail. They’re putting an ARM 9 CPU in a pen. A pen with a diameter of 15mm. Does anyone know if an ARM 9 is made in that small of a package? We’ll have a full, “this is a totally unrealistic Kickstarter and you’re all sheep for backing it” post when it finally launches. Also, this.