During the summer months I love flying and testing out my UAV projects. But during the winter months, the lack of daylight and the bad weather really doesn’t let you get outside as much as you would like to. Thus, I started this project, the FI-ApartmentBot. The Goal from the start was to create a robot that would roam around my apartment controlled by a driver via a remote internet connection. The driver would get a live video and audio link to the robot.
Note: The ApartmentBot runs on any Arduino compatible microcontroller. Thus, you will need the Arduino IDE to compile and load the code to your board. The ApartmentBot also uses the Digi Xbee wireless modems to communicate to the host controller. I use a Sparkfun Xbee USB Explorer to connect the host Xbee module to my server. The Xbee communicates over a serial connection at 9600 baud, be sure your baud rate is set properly.
All of the parts needed to build the ApartmentBot can be easily purchased from your local electronics store or online. Follow the links for each part below to easily locate them on Sparkfun.com
The user based commands and code is located in the UserControl.pde file. The following is how to properly construct a command to get the rover moving.
Example Command: “f200#”
Be sure to terminate every command with a #. This is to verify that the command is complete due to the fact that command can be written with multiple line returns.
By default the roving system is deactivated until activated by the user.
You can easily change the way the rover acts on boot and have it rove by default. The main sketch file in the source code has a boolean value that can get changed named roveMode.
boolean roveMode = false;
Setting rove mode to true will allow the roving to be initialed on boot. You can also turn on rove mode from manual control mode. Passing roveMode=true# via serial command on a baud rate of 9600 will activate roving until the boolean is set back.
I use a ADXL335 Triple Axis Accelerometer onboard the rover to calculate if the rover is driving on a valid angle that will not allow it to tip over. The ADXL355 allows for fast polling which is needed for when the rover is quickly moving in any direction. The sooner that a potential tip can be calculated the better.
The LIPO batteries onboard the robot carry 3.7V with 2amp of power per battery. In series the batteries produce a 7.4V output which unfortunately to high to wire into a Arduino analog I/O. A simple voltage divider can cut the voltage in half and allow us to compensate the division with software.
These two 10k resistors (R1 and R2) will cut the voltage directly in half and we can then connect the Vout to Arduino analog pin 0. Using the code example below, we analogRead(0) to get the divided voltage calculation. Reading pin0 as a 10bit value mean we would calculate the real voltage as:
const int voltageReadPin = 0;
const int voltageUnitValue = 0.0048828125;
void setup() {
Serial.begin(9600);
}
void loop() {
int voltageVal = analogRead(voltageReadPin);
int batteryVoltage = voltageVal * voltageUnitValue * 2;
Serial.println(batteryVoltage);
delay(1000);
}
Feel free to contact me anytime by any of the mediums listed on the about page or via the contact form below.
Email: fisher.matt at gmail.com