[Kc7fys] came up with a this simple battery level indicator. It uses a single LED to display a battery’s voltage; if the voltage exceeds 12V, it glows green. If it is below 11V, the LED glows red. Anything in between generates an orange glow. The meter is built around an LM358 chip per this schematic, but his actual build looks pretty sloppy because of the dead-bug assembly (check out NASA’s pretty version). Nonetheless, it works, so clean it up and build one if you want to put it (or your batteries) to the test.
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LED Painter
The people at Brilldea have come up with LED Painter, a 16-channel RGB LED controller capable of controlling up to 48 independent LEDs. It uses a Texas Instrument TLC5940 to control the LEDs and can be connected to more LED Painter boards, creating a large array of RGB lights. The TLC5940 itself has been modified to make connecting independent LEDs easier.
The team strung together nine of these along with a Propeller-based controller called a Prop Blade and fitted the lights into three windows with semi-opaque glass to create a display of dancing randomized RGB lights. If all the dancing lights have inspired you, the TLC5940s are fairly inexpensive, but you’ll need both through-hole devices and some SMT components to get if off the ground.
Tom’s RGB Mood Lamp
[Tom] has been refining a board that drives a high power RGB LED for applications like this moodlight. It’s based around an ATmega8 microcontroller. The goal was to make an RGB LED easy to work with: It can cycle between colors in standalone mode. You can control it via a serial interface. It also has a pin header to hooking up three potentiometers for manual color mixing. Boards aren’t available yet, but he’s already posted a build tutorial. The board looks straightforward enough that it shouldn’t be too hard to layout if you really want to.
Turn Signal Jacket How-to
[Leah Buechley], whose work we’ve been covering since way back when, has built this lovely turn signal jacket. The project photos were posted in March, but she’s just added a well illustrated project guide. The jacket is based around a LilyPad Arduino, a lightweight Arduino board with radial pads designed to be used in wearable projects. You make your connections by sewing conductive thread through the pads. The how-to covers attaching the LilyPad parts properly and then insulating the wires with fabric paint after you’ve verified they work.
The guide has an interesting discussion about placing the power supply. The 4-ply silver coated thread used has a resistance of approximately 14ohms/foot. So, if you place the power supply one foot from the LilyPad, the two wires combine for 28ohms, causing a 1.4V drop. The power supply is only 5V, which means the LilyPad will be 3.6V. A voltage of 3.3V will cause the Arduino to reset. If your resistance is too high, you’ll have to add more thread.
The power supply on this jacket is under the collar. Each cuff has a single button plus an LED. The button will make the jacket flash the direction for 15 seconds (also indicated on the sleeve LED). If you press both buttons at the same time, it switches to night mode by flashing both directions at the same time to make you more visible.
3x3x3 LED Cube
[portreathbeach] built this simple 3x3x3 LED matrix. It uses a PIC16F690 in a ZIF socket for the brains. Each layer has nine LEDs with the cathodes tied together. The anodes from each LED are connected to the LED below. The LEDs are multiplexed so that even though all layers appear to be on, they’re being addressed individually. He’s included software, so you can build your own animations. Video of the matrix in motion is after the break.
How-To: Make An RGB Combination Door Lock (Part 2)
In part 1 we showed you how to build your own prototype RGB keypad. Today we’ll show off some new ideas we worked on to create the project and turn it from prototype to fully functional battle station er door lock.
Continue reading “How-To: Make An RGB Combination Door Lock (Part 2)”
High Power LED Blinking Circuit
[youtube=http://www.youtube.com/watch?v=mNDu56oGNck]
Evil Mad Scientist Labs brings us this easy to make LED blinking circuit. The idea is to put a LED in series with a small blinking incandescent bulb from a string of Christmas lights. The bulb has an internal bimetallic strip that bends out of shape when it heats up, cutting the circuit. when it cools enough, it returns to its original shape and closes the circuit again, making the bulb and the LED turn on. Both lights have short period of sustained light when they are initially powered up since the bimetallic strip is still warming up.
The project uses a 5W blue LED, the aforementioned bulb, and a 6V battery pack loaded with 3 AAA batteries. The battery pack and the lights are all attached to a small section of perforated board. Duplicating this project should be easy and provide a very bright LED, but to make a 5W LED shine its brightest, a larger bulb and a heatsink will be necessary.
