Motion Activated Alarm for your Bag

Many of us carry around a bag with our expensive personal belongings. It can be a pain to carry a bag around with you all day though. If you want to set it down for a while, you often have to try to keep an eye on it to ensure that no one steals it. [Micamelnyk] decided to build a solution to this problem in the form of a motion sensing alarm.

The device is built around a Trinket Pro. The Trinket Pro is a sort of break out board for the ATMega328. It’s compatible with the Arduino IDE and also contains a USB port for easy programming. The Trinket is hooked up to a GY-521 accelerometer, which allows it to detect motion. When the Trinket senses that the device has been moved, it emits a loud high-pitched whine from a piezo speaker.

To arm the device, the user first holds the power button for 3 seconds. Then the user has ten seconds to enter their secret code. This ensures that the device is never armed accidentally and that the user always remembers the code before arming the device. The code is entered via four push buttons mounted to a PCB. The code and code length can both be easily modified in the Trinket software.

Once the code is entered, the status LED will turn solid. This indicates to the user that the device must be placed stationary. The LED will turn off after 20 seconds, indicating that the alarm is now armed. If the bag is moved for more than five seconds at a time, the alarm will sound. The slight delay gives the user just enough time to disarm the alarm. This parameter can also be easily configured via software.

Color changing bag matches clothing color, tells you what’s inside


Adding some lights to your everyday items will certainly give you a style leaning toward the world of Blade Runner. But if you can add functionality to control the blinky components you’ve actually got something. A great example of this is [Kathryn McElroy’s] Chameleon Bag. It’s a shoulder bag with a light-up flap. It can color match your clothing, but she also built some features that will let you know what is inside of the bag.

The project started by using a cardboard template in the size and shape of the bag’s flap. After adding an Arduino to control the LEDs and an RFID reader for an interactive element she sewed a replacement flap that also acts as a diffuser. In the video after the break she demonstrates matching the color of her scarf by reading a tag sewn in the end of it. She then starts loading up all the stuff needed for a day away from home. As the keys, phone, and computer are placed in the bag their tags are read, resulting in different combinations of color. Once everything she needs is inside, the flap turns green and she heads out the door.

This will go great with your illuminated umbrella.

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Key-covered textiles

[Karolina] has been hard at work adding a little flair to her bag. Well, a lot of flair actually. She rolled several keyboards worth of keys into one of the panels for this bag. She had seen the idea in a magazine and decided to give it a try. The secret is to use staples.

The first issues is gather enough keys, so if you give this a try make sure to let your friends know you’re looking for old keyboards. Next she wanted each of the keys to lay flat on the fabric panel, which meant cutting away the plastic pegs that extend past the edges of the key. From there [Karolina] laid out her design with each key face down. Notice how careful she was to make sure there were no gaps between them. Now it was time to link them all together. She used heavy-duty staples as connecting brackets. They were bent to provide a large gluing surface on the underside of the face of each key. With the staples in place, each can be sewn to the fabric with a loop of thread. Although she started the project in the fall she’s just now showing off the finished bag.

Punching accelerometers

Shortly after finishing his Makiwara punching bag, [Abieneman] wired and programmed an Arduino to an accelerometer to find out just how much acceleration (and with some math, force) is behind his punches. The project is simple and would be quick to reproduce for your own measuring and experiments: all that he used included an Arduino, accelerometer (with A/D converter), LED displays (and shift register). We were a little disappointed to learn of how much static the accelerometer produced, so measuring things such as impulse, energy, and pretty much anything not kinematic is nullified. But it makes us wonder, how much static would be in say, a Wii Remote punching bag?