Make Robot-Wifi-part2

Hardware

Car
Adding a network camera, router, heavier batteries, extra circuits, and a whole bunch of wires adds a lot of extra weight that the car wasn't designed for. Because of all of the additions, you'll need to find a pretty large RC car. Thrift stores often sell RC vehicles (without remotes!) for $3-5. I have bought a number of cars this way for taking apart. Vehicles in the 1:10 size ratio or bigger are appropriate; you probably don't want to go any smaller. I bought this car for $5 at Value Village.

I have taken apart about 20 RC cars. Nearly every single one of them used the Realtek RX2/TX2 chips or a pin-compatible alternative. The links are for their respective datasheets. What this means is that it's really easy to interface to the car's existing electronics without having to put in a bunch of our own circuitry. It's possible to hook up a microcontroller directly to these pins (Forward, Backward, Left, Right) and directly control the car. Being able to leverage the car's original circuitry saves a lot of time and effort.
Router

I've modified my WRT54GL to have 2 serial ports and a 1GB SD Card (acts like a 1GB hard drive). The SD card is not used in this project, but one of the serial ports is. One is a console port, the other is TTS/1 which we will be using. For this project I'm using Open-WRT White Russian v0.9. There are more recent versions, but we don't need the latest-and-greatest software features for this project. The software compilation guide (details later) uses this distribution, so that is why I chose it.

Later in the article links and information are given that can help you wire up your serial ports and get them working.