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Siemens SX 2.0 - 2012

Since I've stated with programming J2ME applications, I've dreamed about building an actual robot. So I did some research and came up with plans for a robot controled by a J2ME application in a phone.

One of the problems with building a phone-based robot is how to communicate with it. Fortunately, certain phones have UART directly build into the connector. I used Siemens C65 which has UART directly accessible on the 12-pin charging connector and programmed an Attiny2313 processor to listen to the phone's commands. The chassis consisted of 4 AA bateries, 2 motors, the control board with Attiny2313 and the Siemens phone and everything was hot-fixed with a lot of hot glue. The robot did have only one sensor, the phone's internal camera.

Siemens 1.0

It could do some basic image recognition (like following a specific color in the image), but the lack of sensors was quite limiting leading up to a second version.

Siemens SX 2.0 is the necessary upgrade. I've replaced the phone for Siemens CX75, that offers a better camera and bluetooth. I've added 3 IR obstacle sensors, 2 bumpers, 4 IR line sensors and 2 servo motors to pan and tilt the phone (and it's camera). Motors are still connected to the control board with Attiny2313 from the previous version, sensors and servos and other added hardware is connected to a new board with an Atmega8 chip. Both boards are communicating through UART with the main J2ME application running on the phone. I've replaced the wheels and cover some of the electronics with a green paper shell.

Siemens SX 2.0

The robot is capable of following a line, avoiding obstacles and doing some basic stuff with camera vision, like going to a particularly colored object or navigating itself through a color-coded environment. In the video below I control the robot via bluetooh, take a picture from the camera and turn on the LED diode on top.

Creating the logic of a robot inside a J2ME application was far from ideal. Even though the cell phone has more than enough processing power, the phone's environment constantly gets in the way. Just starting the J2ME application from the phone's menu is a pain, not mentioning the requirement to insert a SIM card to start up the phone. Using a proper platform would save a lot of problems... and time.

Siemens SX 2.0 - back

Also... mounting the cell phone on 2 servo motors was not a good idea. It is unstable, the robot is fragile and the pictures are degraded by a motion blur artifacts.

Siemens SX 2.0 - servos

But after all it was a great learning tool that had taught me more then anything before.

With the first version I have took a part in a robotic contest named Istrobot and ended up in a great 3rd place.
It was my first success in the field of electrical engineering and it definitely pushed me forward!