RFID security badge. For those small companies who can't afford such extravagantly wireless door key solutions there's another option: this DIY project completed by a team of developers at Sunlight Labs. It all centers around a Linksys WRT54GL, a Linux-based wireless router that, with a little firmware hackery and a bit of wiring, was tethered into the office's door release buzzer. The team then went about allowing SSH access to the router and created Android and iPhone apps that instantly connect to the device and open the door, authenticated by a PIN and a unique ID assigned to each device. Users can also deliver their PIN via SMS or a simple phone call to open the door. Elegant, impressive, open source, and one less thing to forget on a Monday morning when groggily heading to the office.