How-To: Make An RGB Combination Door Lock (Part 1)


Part 2 can be found here

Putting a custom designed electronic lock on your space seems like a geek right of passage. For our latest workspace, we decided to skip the boring numbered keypad and build a custom RGB backlit keypad powered by an Arduino. Instead of typing in numbers, your password is a unique set of colors. In today’s How-To, we’ll show you how to build your own and give you the code to make it all work.

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Accelerometer Mouse From Scratch


[Mahavir] sent in his group’s final project for the College of Engineering in Pune (it’s over here). They built an accelerometer based Bluetooth mouse. They ended up creating a mouse that maps rotational movements to x/y motion. From the video movement, it strikes us as responding the same way that touch pointer mice do. You can hit the demo video after the break or get more details from the project page. Even if you’re not into the mouse idea, you can probably learn something from their Bluetooth implementation.

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DIY HID Ballast


HID lights have a major power consumption and lumen output advantage over halogen lights. Unfortunately the ballast component isn’t very cheap. [brian]’s been building his own ballasts for his mountain bike. We couldn’t find any more info on his design, but we did find some interesting stuff. This document lays out the requirements for a ballast. Here’s an older HID ballast design to get rolling. Keep in mind that the lamp requires high voltages – don’t play with it unless you know what you’re doing. If you’d rather use off the shelf components, check out the HID dive light we wrote up a while back. It uses a fairly inexpensive ballast/lamp combo.

RGB Laser Diode Projector


[fl-consult] published this interesting RGB laser diode projector. The build uses three lasers, 532nm green, 660nm red and a 405nm blue diode from an XBox 360 HD-DVD drive. Aside from the salvaged diodes, it uses some off the shelf hardware to power and scan the lasers to make the display. Details are a bit lacking, but google translate helps a bit. If you’re not quite sure what’s going on: the three lasers bounce off of a set of mirrors that scan from side to side as well as up and down to create images.

IR Controlled Relays


If you’re thinking of building some DIY home automation, this looks like an interesting idea. At the heart is a PIC16F84 that decodes IR signals and controls six outputs – in this case, relays to activate various appliances. The PIC is dirt cheap – if you get a deal on some relays you should be able to build a small local IR HA system for $30… This might be just the thing for my office. It’s cheap enough that it probably wouldn’t walk off.