Hey whats up guys! Its been a while since I last posted but I’ve got some interesting stuff to post on now. In one of my last posts I had said that I was going to build a wii remote controlled robot, well I sort of made it. I scrapped the wii remote and replaced it with a pc(laptop). The robot is a standard vex tank chassis constructed from two long plates connected with standoff beams. It is driven by 1 vex motor on each side so a total of 2 motors were used. The motors are running off a 12v battery pack which gives around a 30% increase in rpm and torque (I could be wrong on how much) over the standard 9v that the vex controller uses. The “brain” or microcontroller is an arduino board, this board is connected to a pc via a bluetooth serial connection using a bluesmirf from sparkfun (I LOVE THE BLUESMIRF…:D). On top of the robot is a vex explorer wireless camera. There are two sensors on the robot (ultrasonic,light) that send data back to the computer. The microcontroller and the camera are powered separately by two individual 4.8v slim battery packs.
On the software side I used visual studio.net 2008 to write an application to allow control of the robot over serial. It has the ability to receive and display data from the sensors as well. On top of that it can even alert you remotely before the robot hits a wall or obstacle! The W,S,D, and A keys are used to drive the robot (your standard fps keys).
So all in all I think this was a very interesting build and I would like to hear what you guys think about it!!!
The normal battery is actually just 7.2v, but the AA holder filled with alkaline batteries would be 9v. I am pretty sure the Vex brain wouldn’t appreciate 12v, but I’m not sure about the motors. Obviously they don’t instantly burn out
Neat little use of the Arduino, I’d been wondering if there was a way to use a pair of the wireless “bee” chips (I forget the name) to allow vex to vex communication.
“The operating range of the Vex Controller is 5.5 – 9.0 Volts which will be applied to the Vex Motor. If the Vex Motor was not connected to a Vex Micro Controller, the Vex Motor has a range of 4.4 – 15 Volts. Motor life will be reduced operating outside the Vex Controller range”.
I believe the wireless chips you are referring to are called Xbee modules. I have looked at them but it was a more expensive route as I would have needed two modules ($23 - 82) each, a computer adapter $25, and the arduino Xbee shield $25. These bluetooth modules can accomplish this as well, once connected you can open a serial terminal say teraterm and send commands to it which can reconfigure it to work in a pair with another module. This is obviously expensive at $65 each but its worth it! Xbee is great for long range though, the most powerful module sparkfun sells can reach 15 miles line of sight! I’m not exactly sure why two vex robots would need 15 miles worth of communication range,… maybe they are evolving?
As for the motor voltage I had read the specs on the motor before attempting this to be sure that 12v wouldn’t burn it out. I would have gone with 15v but at that voltage your playing a dangerous game because just a bit more and it will fry so I went with 12v just to be safe.
Someone commented on my video and asked me to make it wii remote compatible so I did just that. Its essentially the same robot except the wii remote is whats used to control it… go figure. It has some extra nifty features like the lights and vibrating motor for object detection!
Here is the video!!!
If that link doesn’t work just go here and click on the latest video.
