Global Domination Robot (GDR) Mk 2

Update 28 NOV 12:

- I've fiddled with the targeting code and now have it written correctly so that the GDR will enter "Sentry Mode", will scan 180 degrees using an ultrasonic rangefinder on a turret, will record the distances to everything in front of it, and then will scan back and forth and will stop and fire on anything that approaches (change in distance from previously set distances)

- I have some issues with performance on these scans as sometimes the GDR will perceive a difference in distance when none exists.  I believe this is due to a lack of regular power to the rangefinder.  I have to do some more research to see if there's a way to fix this through the use of capacitors, or running a separate power source directly to the rangefinder.  Currently it is powered (along with two servos and a laser pointer) directly from the arduino.

- My "laser death ray" has stopped working on the pin that I had it running on.  A friendly helper on one of the arduino forums pointed out that since the laser pointer is designed to run on 3V 35mA, when I run it off 5V it is likely drawing more mA than the pin socket can handle and is burning it out.  Time to do some math to figure out what size resistor I need to put in the line to the laser to bring the 5V output back down to 35mA.

- I've replaced the large wheels and caster of the GDR with a pair of tracks.  Robot moves far slower now, but is a lot more stable.

Update 22 NOV 12:

Here is the GDR Mk 2. I've recycled the parts from the GDR Mk 1 and made some additions/upgrades:

- Built a body for the robot out of a couple of storage boxes

- Added a 2 POF Turret to the top

- attached a laser pointer to the turret and programmed it to aim and fire

- split the power so there is now dedicated power to the motors.

I'm fairly happy with the outcome of the GDR Mk2 so far. Right now he just navigates around with the ultrasonic, avoids obstacles, and every now and then he pans the turret around and engages enemies with his laser. Its not really targeting anything right now, its just going to set locations for deflection and quadrant (the two POFs of the turret) and firing in a pre-programmed pattern.

This could be considered "complete" at this point based on my GDR development plan below, but I'd like to experiment with some of the Mk 3 upgrades on this build. I think I can work some of my Mk 3 upgrades (see plan below) just with changes to the programming code, but we'll see. To make it actually target someone/something: I plan to have it stop now and then, scan distances at different angles in front of it, record those distances, and then continue to scan and anytime something breaks those distances (a person or object approaches) it will fire at them with the laser pointer. I would like to have the ultrasonic get the size of the object it detects by having it pan right/left and up/down and recording when the distance changes (sides of the object) and then firing the laser at the midpoint. I'll have to play with it to see how it works.

The other upgrade that will move this to the Mk 3 model will be the ability to navigate to a specific location to set up sentry. Would love any input or advice that people could give me on this.

GDR model plans:

- Mk 1: First Bot, just an obstacle avoider

- Mk 2: Simple navigating robot that occasionally stops, pans turret around and fires "weapon"

- Mk 3: Upgrade navigation to go to move to a specific location and "guard" (would love input on the best method for this. GPS?) once in position will scan with ultrasonic sensor and when object/person approaches will target and fire on them.

- Mk 4: Upgrade size of chassis (with an old scooter or golf cart?) and replace laser pointer with an airsoft or paintball gun.