Arduino Hacks

3055 Articles

Water Gun

Motion Sensing Water Gun Tweets Photos To Embarrass Enemies

June 22, 2015 by 14 Comments

[Ashish] is bringing office warfare to the next level with a motion sensing water gun. Not only does this water gun automatically fire when it detects motion, but it also takes a photo of the victim and publishes it on Twitter.

This hack began with the watergun. [Ashish] used a Super Soaker Thunderstorm motorized water gun. He pulled the case apart and cut one of the battery wires. he then lengthened the exposed ends and ran them out of the gun to his control circuit. He also placed a protection diode to help prevent any reverse EMF from damaging his more sensitive electronics. The new control wires run to a MOSFET on a bread board.

[Ashish] is using a Lightblue Bean board as a microcontroller. The Bean is Arduino compatible and can be programmed via low energy Bluetooth. The Bean uses an external PIR sensor to detect motion in the room. When it senses the motion, it activates the MOSFET which then turns on the water gun.

[Ashish] decided to use Node-RED and Python to link the Bean to a Twitter account. The system runs on a computer and monitor’s the Bean’s serial output. If it detects the proper command, it launches a Python script which takes a photo using a webcam. A second script will upload that photo to a Twitter account. The Node-RED server can also monitor the Twitter account for incoming direct messages. If it detects a message with the correct password, it can use the rest of the message as a command to enable or disable the gun.

Visualizing Magnetic Fields In 3D Space

June 21, 2015 by 31 Comments

[John] is working on his PhD in experimental earthquake physics, and with that comes all the trials of becoming a PhD; tuning students into the cool stuff in the field, and demonstrating tech created after 1970 to his advisers. One of the biggest advancements in his line of work in the last 30 or 40 years is all those sensors you can find in your cell phone. The three-axis magnetometer in your phone is easily capable of measuring the Earth’s magnetic field, and this chip only costs a few dollars. To demonstrate this, [John] built a 3D compass to show off the capability of these sensors, and have a pretty light show for the undergrads.

The magnetometer [John] is using is just a simple I2C magnetometer that can be found on Adafruit or Sparkfun. It’s not really anything special, but with a little bit of code, [John] can read the magnetic field strength in the x, y, and z axes.

Having a microcontroller spit out a bunch of numbers related to the local magnetic field just doesn’t seem fun, so [John] picked up two neopixel rings – one inside the other, and set 90 degrees out of plane with each other. This turns his magnetometer and Arduino setup into a real 3D compass. With this device, the local magnetic field can be visualized in the x, y, and z axes. It looks cool, which is great for undergrads, and it’s a great demonstration of what you can do with small, cheap electronic sensors.

[John] put up a screencast of a talk he gave at the American Geophysical Union meeting last year. You can check that out below.

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Neopixel Ring Compass Takes Things In A New Direction

June 18, 2015 by 11 Comments

A couple of years ago, [philo mech] came across [David Ratliff]’s NeoPixel compass project. Ever since then, he’s wanted to make his own. To his delight, [philo mech] was able to find time to do just that.

An Arduino Pro Mini drives an LSM303DLHC compass/accelerometer breakout board and a 12-LED NeoPixel ring. The heading is indicated with a red ‘Pixel between two yellow ones.  In the video after the break, [philo mech] gives several demonstrations of the ring’s red indicator in relation to a standard compass arrow.

This colorful compass currently boasts two very useful modes: one to track the whereabouts of North, and the other for determining the user’s current heading. Mk. II  will compensate for tilt and will employ a 16-Pixel ring to display finer degrees of directional change. Want to make your own? The code is pasted in the video’s comments.

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Get Up, Stand Up. With A Little Help From The Mindfulness Bracelet

June 16, 2015 by 10 Comments

[Becky Stern] has created the mindfulness bracelet, a wearable which looks great and serves an important purpose. The bracelet buzzes every hour to remind you to stand up and take a break from work, soldering, gaming, or whatever it is you may be doing. The bracelet is made up of interlinked figure 8 shapes of leather, though [Becky] says rubber from a bicycle inner tube works great as well. The final shape reminds us of the link belts sometimes found on lathes or other industrial equipment. The links are the perfect size to slip an Arduino Gemma in, along with a battery and vibrating motor. A NPN transistor, diode, and resistor round out the entire bill of materials for this design. This bracelet is a heck of a lot cheaper than the Apple watch feature which inspired it!

The time interval is set in the code to 1 hour, and can be adjusted by the user. Although the times are stored in milliseconds, the design does use the ATtiny85’s Watchdog Timer (WDT) to conserve power. This means the time can drift up to 30 seconds per hour, which is fine in this application.

Click past the break to see the bracelet in action!

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IOT Lawnmower

World’s First Internet Connected Lawnmower

June 10, 2015 by 16 Comments

Okay so this IOT is getting a bit out of hand. Introducing the world’s first(?) tweeting, internet connected, lawnmower.

[Michel] recently bought one of those new-fangled cordless lawn mowers by EGO. It runs off a 56V lithium ion battery pack, and apparently, works pretty well. Since it has plenty of on-board power, he decided to strap a 64MHz PIC18F25K22 to a ESP8266 and connect it to the internet. That part number has been taking the world by storm and it’s totally freaking awesome. The ESP8266 is a tiny WiFi module that is controllable over a serial port — and it only costs $5. Hello IOT-everything.

Anyway, to avoid voiding his warranty, [Michel] using non-invasive sensors to collect data — A series of hall effect sensors and magnets to be exact. One detects when the cutting system is engaged, and another magnet and sensor pair counts wheel revolutions. In the end, this gives you data on how far you pushed the mower, how long you spent cutting, and how long you were out there. When the job is done, you have the option to push a tweet with your stats. Woo!

He does admit, the tweeting feature is more there just to annoy his friends.

Skateboard

On Your Phone While Driving An Electric Skateboard

June 9, 2015 by 28 Comments

Skateboards are fun, but you have to do all that pesky kicking in order to get anywhere. That’s why [Nick] decided to build his own electric skateboard. Not only is the skateboard powered with an electric motor, but the whole thing can be controlled from a smart phone.

[Nick] started out with a long board deck that he had made years ago. After cleaning it up and re-finishing it, the board was ready for some wheels. [Nick] used a kit he found online that came with the trucks, wheels, and a belt. The trucks have a motor mount welded in place already. [Nick] used a Turnigy SK3 192KV electric motor to drive the wheels. He also used a Turnigy electronic speed controller to make sure he could vary the speed of the board while riding.

Next [Nick] needed some interface between a smart phone and the motor controller. He chose to use an Arduino Nano hooked up to a Bluetooth module. The Nano was able to directly drive the motor controller, and the Bluetooth module made it easy to sync up to a mobile phone. The Android app was written using MIT’s App Inventor software. It allows for basic control over the motor speed so you can cruise in style. Check out the video below for a slide show and some demonstration clips.

It’s a popular project, and eerily similar to the one we saw a couple months back.

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Pendulum MIDI Controller Really Swings

June 3, 2015 by 16 Comments

Once in a while, we see a project that makes us want to stop whatever we’re doing and build our own version of it. This time, it’s Modulum, a pendulum-based MIDI controller. It’s exactly what it sounds like. The swinging pendulum acts as a low-frequency oscillator. In the demo video configuration, you can hear it add a watery, dreamlike quality, sort of like a lap steel guitar on LSD.

The pendulum’s motion is detected by four pieces of stretchy, conductive cord. These are wired to an Arduino Nano in a voltage divider fashion. [Evan and Kirk] used the Maxuino library to determine x and y mapping of possible pendular positions as well as perform the necessary MIDI processing. Get your groove on after the break, and check out some of the many other fantastic MIDI controllers we’ve had the pleasure of covering.

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