Beginner Project: Super Cheap Magnetic Mixer

March 16, 2011 by Jesse Congdon 23 Comments

[wesdoestuff]’s mother needed a clean way to mix together fragrance oils. Being the stand up kinda guy he is, [Wes] threw together a few spare parts to make this Magnetic Stir Plate.

The whole setup is amazingly simple. Pry the fins off of an old computer fan, glue a couple magnets to the fan’s hub. Drill a hole for a DC connector, find some sort of cover and.. Bob’s your uncle! [Wes] advises that you test the spacing of the magnets on the hub before gluing them permanently, as they can be a bit tricky to align.

The stir bar for non food items is a magnet bar from one of those crazy magnet and ball bearing toys, it is basically just a solid magnet covered in plastic. Food safe bars can be acquired, though they are not as cheap. With all that room under the hood we would love to see him throw in some kind of a PWM speed control but that could be a bit complicated. Most of us could throw this together from spare parts. Video after the jump!

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Electronic Diaper Bag Reminds You To Pack Everything But The Baby

March 15, 2011 by Mike Nathan 15 Comments

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[jnorby] knows what it’s like to leave the house with her baby in tow, only to realize that she has left something she needs at home. Instead of relying on a paper checklist, she decided to craft her own diaper bag that alerted her if she had forgotten to pack a particular item.

She built her bag from scratch, wiring small circuits into each of the pockets she created on the inside of the bag. Wires were run to each half of a snap fastener, so that they would complete the circuit when the snaps touch. The LEDs and snaps were then connected to a LilyPad Arduino, which checks the status of the snap circuits, lighting the appropriate LED once the proper item has been packed.

While we like the idea of a bag that uses functional indicators that remind you to pack items, we do think that the use of the Arduino, or any microprocessor for that matter, is massive overkill. We would ditch the LilyPad and snap fasteners for reed switches or perhaps normally closed micro leaf switches that turn the LEDs off once the proper item has been packed, rather than the other way around.

Automatic Ball Launcher Is For The Dogs

March 15, 2011 by Mike Nathan 24 Comments

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A while back, [Dino] built an automatic ball launcher for his dogs, but he wanted to revise it to make it smaller and a bit more user-friendly. While watching an episode of “Prototype This”, he came across a great idea to improve his launcher, so off to the workshop he went.

He repurposed a power window motor from a car, and mounted it to some wood-reinforced aluminum sheeting in his garage. He added a piece of aluminum tubing to serve as a spring-loaded launch arm, which is drawn back by a small lever attached to the window motor.

When a ball is dropped onto a switch at the bottom of the launcher, the window motor starts turning, which pulls the launch arm back into place. Once the arm reaches the tipping point, the spring snaps it forward, launching the ball across the yard. The lever attached to the window motor eventually makes its way back under the launch arm, and is stopped by a switch that is also attached to the motor.

After the prototype was finished, he added some more wood to protect the mechanism from his dogs and vice versa. A hopper was added to the top of the structure to allow the dogs to load the launcher themselves, after a bit of training.

Now, some of you might wonder what is wrong with [Dino’s] arm. Truth be told, it works just fine. If you are a frequent Hack-a-Day visitor, you know that he spends plenty of time in the workshop, so this is an easy way to let the dogs entertain themselves until their owner is ready to play.

Check out the video embedded below for a demonstration of the launcher, as well as a detailed walkthrough of how the mechanism works.

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Wireless Weather Station Obsessively Reports The Temperature

March 15, 2011 by Mike Nathan 11 Comments

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[nuumio] has been hard at work building a Tweeting weather station, which he recently got up and running. The weather station is built from three major components, a Linux PC for data storage and Tweeting, a main weather sensor unit, and a remote unit.

The remote unit sits outside and includes includes both a pressure and humidity/temperature sensor. The sensors are polled every 20 seconds, reporting the data back to the main unit via a 434 MHz RF transceiver. The remote sensor also records the ambient light level and the remaining battery voltage, sending that data to the main unit for good measure.

The main unit sits inside his house and records the same temperature and humidity data as the external unit. The main unit adds its data to the packets sent by the remote unit and transmits them to the PC via USB. The PC calculates the minimum and maximum temperatures for the last 12-hour and 24 -hour periods before sending that data back to the main unit to be displayed on its LCD panel. Every 10 minutes, the computer also posts the weather data on Twitter.

If you are looking to build your own weather station, [nuumio] has provided all of the source code for his project on his web page. However, he does admit that he was too lazy to draw up a schematic, so you are on your own in that department.

Control Your Home Theater From Anywhere In The World

March 14, 2011 by Mike Nathan 21 Comments

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Using IR repeaters for larger home theater setups is not uncommon, but they usually are quite simple. A series of IR receivers are placed throughout a home, all wired to repeat the signals in a central closet where all of the AV equipment is located. [Bill] constructed a solution that works much like a standard IR repeater setup, however his requires no receivers, and it can be used anywhere in the world, provided you have Internet access.

His project, called Ether IR, is an Internet-enabled IR repeater. It consists of an Ethernet-connected module with an IR LED mounted on it, capable of controlling your AV equipment. The board is hooked up to your LAN, and relays commands to your home theater via a simple web page. The equipment can then be controlled from any Internet-connected device, such as a mobile phone or tablet PC.

The entire project is open-source, so [Bill] has included schematics, instructions, and a bill of materials so that you can construct your own. The only issue at this point is the software portion of the project. The software is free, but the distribution method is in question – once things are sorted out, he will ensure that you can obtain the software for your Either-IR from him or directly from the Ethernet chip’s manufacturer.

Shedding Some Light On Your Kitchen Chores

March 8, 2011 by Mike Nathan 13 Comments

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[Garret] over at Macetech wanted to supplement the lighting over his kitchen sink, which is always too dark at night. He says his house is a “geek house”, so a standard light socket just wouldn’t do – he would have to construct a LED bar for over the sink instead.

Since nobody wants to use a light switch with wet or messy hands, he did what anyone would do and rigged up a motion detection circuit to automatically turn the lights on and off for him. 16 bright white 10mm LEDs were mounted in some foam core board, along with a PIR motion sensor. He used an ATiny84 to handle the PWM fade-in and fade-out of the lights, as well as to keep track of the activity (or lack thereof) at the sink.

He does admit that the ATiny84 is way overpowered for this project, but he lacked anything smaller, and says that 555 timers wouldn’t give him the smooth light fading that he desired. Regardless, it works as advertised, and now nobody has to peel potatoes in the dark any more.

Continue reading to check out a quick video demo of the motion-sensing light system.

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Bathroom Mirror HUD Displays Time And Weather

March 2, 2011 by Mike Nathan 18 Comments

By and large, the standard household mirror is one item that has not made much real progress over the years. They hang on the wall reflecting light, and that’s about it.

A few years back, some students studying in the Department of Interaction Design at Chalmers University sought to enhance their morning routine with an interactive mirror. Their project was constructed using a two-way mirror with several Arduino-driven LED displays embedded behind the glass. Once a hand is swiped past the pair of embedded light dependent resistors, the display is activated. Subsequent hand swipes trigger the mirror to toggle between the different modes, providing the user with the current time, weather information as well as a toothbrush timer.

The project writeup is quite thorough, including plenty of source code and information on some of the components they used. You can take a look at their work here (PDF).

Check out the interactive mirror we featured that served as inspiration for their project.

[Thanks Emil]

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