Home-Made Solenoid Motor

February 19, 2016 by Richard Baguley 28 Comments

Want to really understand how something works? Make one yourself. That’s the approach that Reddit user [Oskarbjo] took with this neat electric motor build. He made the whole thing from scratch, using an Arduino, 3D printing, and ample quantities of wire to create a solenoid motor. This transforms the linear force of a solenoid, where a magnet is moved by a magnetic field, into rotary force. It’s rather like an internal combustion engine, but driven by electricity instead of explosions. Hopefully.

[Oskarbjo]’s engine seems to work, including a rather neat mechanism to detect the rotation of the shaft and relay that back to the controller. He hasn’t posted much detail in the build process, unfortunately, but did say that “If you’d want to build something similar I can probably help you out a bit, but half the fun is coming up with your own solutions.” Amen to that. We’ve seen a few neat solenoid motor builds, but this one wins points for starting from scratch. There is an Instagram video of the motor running after the break.

Continue reading “Home-Made Solenoid Motor” →

Nerf Turret Controlled By Slack

February 15, 2016 by Anool Mahidharia 11 Comments

What happens when you give a former Navy weapons engineer some development boards and ask him to build “something cool”? What happens when you give a kid finger paints? [Seb] obviously built an IoT Nerf Turret Gun controlled via a team communication app.

The weapon was a Nerf Stampede which was hacked so it could be fired electronically. The safety switch was bypassed and a relay provided the firing signal. The electronics stack consists of an Intel Galileo, a motor shield and a relay shield. The turret assembly was built using off the shelf structural parts from Actobotics. Stepper motors provide motion to the turret. The fun begins with how the software is implemented. An iBeacon network detects where people sit at in the office. So when you type in the name of your target in a messaging app, it knows where they’re sitting, aims at them, and pops a nerf dart at them.

The lessons learned are what makes such projects worth their while. For example, USB is a standard. And the standard says that USB cables be not more than 1.8 m long. [Seb] was reminded of this when his electronics worked on his workbench, but refused to work when placed in-situ and connected via a 3m long cable – the serial link just wouldn’t work.

Mounting the gun such that it was nicely balanced was another challenge. Eventually, he had to use a couple of AA cells taped to the front of the gun to get it right. This could be useful though, since he plans to replace the dead weights with a sighting camera. One last hack was to zip tie heat sinks to the motor drivers, and he had a good reason to do that. Read more about it in his blog. And check out the video as someone takes aim and shoots a target via SLACK, the team messaging application.

Continue reading “Nerf Turret Controlled By Slack” →

Ridiculously Automated Dorm Room

February 13, 2016 by Al Williams 22 Comments

Take three NRF24L0+ radios, two Arduino Nanos, and a Raspberry Pi. Add a bored student and a dorm room at Rice University. What you get is the RRAD: Rice Ridiculously Automated Dorm. [Jordan Poles] built a modular system inspired by BRAD (the Berkeley Ridiculously Automated Dorm).

RRAD has three types of nodes:

Actuation nodes – Allows external actuators like relays or solenoids
Sensory nodes – Reports data from sensors (light, temperature, motion)
Hub nodes – Hosts control panel, records data, provides external data interfaces

Continue reading “Ridiculously Automated Dorm Room” →

Embed With Elliot: Audio Playback With Direct Digital Synthesis

February 12, 2016 by Elliot Williams 39 Comments

Direct-digital synthesis (DDS) is a sample-playback technique that is useful for adding a little bit of audio to your projects without additional hardware. Want your robot to say ouch when it bumps into a wall? Or to play a flute solo? Of course, you could just buy a cheap WAV playback shield or module and write all of the samples to an SD card. Then you wouldn’t have to know anything about how microcontrollers can produce pitched audio, and could just skip the rest of this column and get on with your life.

Harmonic distortion down ~45db on an Arduino — ~45db signal to noise ratio from an Arduino

But that’s not the way we roll. We’re going to embed the audio data in the code, and play it back with absolutely minimal additional hardware. And we’ll also gain control of the process. If you want to play your samples faster or slower, or add a tremolo effect, you’re going to want to take things into your own hands. We’re going to show you how to take a single sample of data and play it back at any pitch you’d like. DDS, oversimplified, is a way to make these modifications in pitch possible even though you’re using a fixed-frequency clock.

The same techniques used here can turn your microcontroller into a cheap and cheerful function generator that’s good for under a hundred kilohertz using PWM, and much faster with a better analog output. Hackaday’s own [Bil Herd] has a nice video post about the hardware side of digital signal generation that makes a great companion to this one if you’d like to go that route. But we’ll be focusing here on audio, because it’s easier, hands-on, and fun.

Continue reading “Embed With Elliot: Audio Playback With Direct Digital Synthesis” →

Robot Does The Worm To Get Around

February 11, 2016 by Dan Maloney 6 Comments

Walking, jumping, rolling, flying, swimming – robotic locomotion is limited only by the imagination of the inventor. [Roger Rabbit] apparently has a pretty vivid imagination, because he’s building robots that move like worms.

Version 1 of [Roger]’s robot is only semi-vermiform and is more of tube climber. It has a pair of 3D-printed pantographs that expand and contract with servos and move along the robot’s axis on a stepper-driven lead screw. An Arduino reads sensors and coordinates the expansion of the pantographs to grip the internal diameter of a pipe and push the worm-bot along. It’s a slow but effective way to get around in the limited confines of a pipe.

The next iteration, dubbed [Wolly], is much more worm-like and not restricted to pipe-running. It has four expandable triangular frames connected to each other with rack-and-pinion backbones. The first frame contracts, the racks push it forward, it expands, the next contracts, and soon it’s doing the worm across the floor. Still slow, but pretty neat to watch, and you can see how it can be steered. It might even be able to roll around its long axis, and it’d make a decent tube climber as well.

This creepy autonomous worm-bot seems very similar to [Wolly], but aside from that we haven’t covered too many robots like these. There’s a lot of thought and effort in these worm-bots, and we’re keen to see where [Roger] takes this unique robot body plan.

Continue reading “Robot Does The Worm To Get Around” →

Constant Innovation And Useless Ducks

February 9, 2016 by Gerrit Coetzee 15 Comments

[Mike]’s hacks aren’t breathtaking in their complexity, but they got a good chuckle out of us. [Mike], the CEO of The Useless Duck Company, lives in a hub of innovation somewhere in Canada, where he comes up with useful gadgets such as a Fedora that tips itself, or a door that locks when you’re shopping for gifts for your wife and you’re in incognito mode.

It all started when he was trying to learn the Arduino, and he put quite a few hours into making a device that could wirelessly squeak a rubber bath duck from the bathroom. The whole project reminded us of our first clumsy forays into the world of electronics, with entirely too many parts to complete a simple function. The Arduino being the gateway drug it is, it wasn’t long before he was building a bartending robot.

We hope he continues to construct more entertaining gadgets.

Continue reading “Constant Innovation And Useless Ducks” →

This Car Lets You Fistbump To Unlock

February 9, 2016 by Al Williams 14 Comments

In the dark ages, you had to use a key to lock and unlock your car doors. Just about every car now has a remote control on the key that lets you unlock or lock with the push of a button. But many modern cars don’t even need that. They sense the key on your person and usually use a button to do the lock or unlock function. That button does nothing if the key isn’t nearby.

[Pierre Charlier] wanted that easy locking and unlocking, so he refitted his car with a Keyduino to allow entry with an NFC ring. What results is a very cool fistbump which convinces your car to unlock the door.

Keyduinio is [Pierre’s] NFC-enabled project, but you can also use a more conventional Arduino with an NFC and relay shield. The demo also works with a smartphone if you’re not one for wearing an NFC ring. Going this round, he even shows how to make it work with Bluetooth Low Energy (BLE).

Continue reading “This Car Lets You Fistbump To Unlock” →