Before exploiting any system, it is necessary to have tools--debuggers, disassemblers, emulators, packet sniffers, and bus adapters--for the job. In low-power embedded systems, implementing the victim protocols is often more difficult than implementing an attack, as a researcher often finds himself to be the very first person to work on a given platform. This lecture concerns the rapid development of tools for exploiting and reversing embedded systems, centered around the concrete example of the GoodFET project. Examples include a voltage glitcher with nanosecond resolution, a radio driver that operates through a hardware debugger, and all the components necessary for reading, writing, debugging, sniffing, and injecting battery-powered devices. The author will bring tools and targets to the conference for those that are interested in trying these techniques out first-hand.