One of the advantages of belonging to a group like the DPRG is that you can almost always find someone who has tried to solve the same problem you're working on and is will to share their solution. In that spirit, DPRG members sometimes write up solutions to common problems faced by robot builders.

Another advantage to a group is that projects that require many talents can be shared among several group members. The DPRG has undertaken several group projects over the years and some of them are documented here.

If you'd like to join one of the group projects seen here or just offer a comment on one of the indvidual projects, why not join us on the DPRG mailing list?

INDEX OF PROJECTS

	Tankbot GTR: A Group Outdoor Robot Project by Ed Paradis and R. Steven Rainwater, December 2006 When DPRG member Bill Cole moved out of state, he left the group a radio controlled Stuart M5 tank made by 21st Century Toys. Around the same time, several DPRG members were looking for a way to get a group project started. The M5 tank toy looked like an ideal platform for a group robot project, so some funds were allocated and we got to work.
	Hacking the Tower Hobbies TS-53 Servo by Dale Wheat, May 2003 Dale starts with a useful general introduction to the use and control of R/C servos. He follows this with detailed, step-by-step instructions for hacking a common hobby servo for continuous rotation. Dale's hack is very elegant, eliminating the modifications to servo electronics that many servo hacks require. While all servo hacks risk damaging the servo, Dale's method is one of the safest and easiest we've seen. It can be easily performed even by robot builders with no previous servo-hacking experience.
	Low-cost Gyro-Accelerometer Combo Sensor by Earl W. Bollinger, January 2003 As homebrew robots grow more sophisticated, they tend to need more advanced sensors. Flying robots and one or two wheeled balancing robots commonly need gyroscopes and accelerometers but, in the past, these types of sensors have been prohibitively expensive. Earl brings the cost down by combining some of the latest solid-state, MEMS-based sensor technologies with some old-fashioned innovation.
	Quickie Servo Tester by Earl W. Bollinger, October 2002 Robot builders frequently use hobby R/C servos either in their original form or hacked for continous rotation. Testing those servos can be a pain because it usually requires either R/C equipment or an operational processor to send commands. Having a simple, dedicated servo tester would make life a lot easier for most of us. Earl has done just that by designing a small, Atmel AT890S2343 based servo tester.
	GARP (Group Autonomous Robotics Project) Updated by R. Steven Rainwater, August 2002 After years of talking about a group robot, the DPRG received an old electric wheelchair from an anonymous donor in New Jersey. Larry Kerns suggested the name "GARP" and things got rolling. GARP's history has been characterized by brief spurts of activity followed by long periods of neglect.
	Home-Brew Shaft Encoders for the Pittman GM8712 Gearhead Motor by David P. Anderson, September 2001 With the help of DPRG and SRS members, David provides a detailed description of the Pittman GM8712 Gearhead Motors and the home-brew encoders he added to them. While the Pittman motors are quite common on the surplus market, David's approach could be applied to other motors as well.
	Improving Servo Positioning Accuracy by David P. Anderson, September 2000 David demonstrates a method of improving both accuracy and repeatability of servo positioning with the use of an external reference potentiometer. This can come in handy when you want to gear up a servo without gearing up the positioning error too.
	Simple NiCad Battery Recharger Ralph Tenny, May 1999 Working with NiCad batteries can seem like black magic to the uninitiated, but it doesn't have to be. This project takes you through building a simple NiCad battery charger with off-the-shelf parts and includes easy instructions for proper care and feeding of NiCads. Project notes include a basic charging circuit, theory of operation, plus calibration and discharging recommendations.
	IR Proximity Detector by Jeff Koenig, August 1998 Proximity sensors are commonly used on mobile robots for obstacle avoidance. This article presents a simple PIC-based, modulated infrared proximity sensor with dual angled transmitters and single receiver. Several DPRG robots use these to successfully navigate our contest courses. The article includes a detailed parts list, PCB layout, schematics, theory of operations, and source code.
	Cirrus CS-21 Sub-Micro Servo Hack by Jim Brown, April 1998 A great step-by-step pictorial about modifying a sub-micro R/C servo for continuous rotation. The ideas clearly presented here can be used to modify most servo motors and leaves 1st-time servo hackers with confidence to convert almost any R/C servo motors into easy-to-use drive motors.
	L298 H-Bridge PCB by Jim Brown, April 1998 A simple H-Bridge for motor control is needed by almost every robot builder. Several DPRG members got together and, over the course of several RBNOs, designed a printed circuit board for an L298-based H-Bridge. The PCB artwork can now be used by others to create this simple circuit that interface a pair of motors with a microcontroller.