This Tutorial was created by Kevin Rockwell and Colin Wilkie
The Autonomous Turret
Objective: To create an autonomous turret that will fire an airsoft gun using an FPGA.
Our goal has been to create a robotic turret and we chose to design one that can eventually be autonomous. We are just finishing Phase 1, which is the first prototype of the robot and will be controlled manually. Once we finish this phase we will make the decision to either go fully autonomous or do something else, perhaps control through an iPhone with a live video feed.
Unlike most turret projects ours is based off an FPGA(Field Programmable Gate Array) rather than a microcontroller. The advantage of using this board is the ability to write code and have it synthesized into hardware. This approach requires a bit more coding and in the VHDL language rather than in C# or the other languages that many microcontrollers use.
Furthermore, we tried to keep the expense of the project to a minimum; so far it has only cost $100, making it considerably less expensive than other guides. The bulk of the costs came from the servos at $30 each, and the last bit came from purchasing P-Mods and the actual firing mechanism (more on these later). If you own an FPGA or are planning on purchasing one, you will find our guide is an easy and fun way to gain experience using the board and its many features.
This project consists of multiple steps. It will guide you through building the housing and which materials are best to use. It will include instructions on installing and controlling servos and which types are the best to buy/use. You will be able to create a variety of programs in VHDL and the tools to begin new projects featuring the FPGA. At the end of this guide you will have yourself a nice looking controllable robotic turret as well as the knowledge to use UART protocols, seven segment displays, LED’s, servos, basic VHDL, and power usage.
This project will require the following supplies, for more information continue to the next page:
An FPGA, we use the NEXYS board: http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,797&Prod=NEXYS
The free software from the Xilinx website: Adept 2.0 and Xilinx ISE 11
USB cable: should come with the FPGA or you can buy one at any electronics store
Servos: for more information visit the Servo Page
Housing: for more information visit the Housing Page
Power: for more information visit the Power Page
Three Peripheral Modules: for more information visit the P-Mod Page
A PS/2 Keyboard for manual control: for more information visit the keyboard interface page