[help] - 12x3PI wireless control from PC

Our project is on AI and I think 3pi matches our basic hardware needs.

Our task for hardware is to build 12 robots controlled by one PC using wireless medium. PC will give commands to robot (move forward, backward, turn left, turn right etc) and robot will keep sending all raw data from sensors.

We are not really into hardware, can you guys help us in building hardware specification for the same.

We don’t need LCD in 3pi
10 meter wireless range will do.
We need precise control on distance traveled and angle movements of robots (speed not important), encoders will do?

As I think encoders are not included as part of 3pi (please correct me if I am wrong) and provided we don’t need LCD, will it be a better choice to build it using chassis and other parts ourself?


The 3pi does not have encoders, so you are correct that using the RRC04A chassis might be a better option for your requirements. Since you don’t need an LCD, I’d recommend controlling the robot with a Baby Orangutan. The Baby-O does not have an LCD and it has more I/O than our other robot controllers. The chassis page has a list of the required components you will need to build a robot with it.

The Baby Orangutan powers its motor driver directly off of VIN, which means as your battery voltage decreases the power to your motors will decrease. This means that the speed of your motors will be dependent on how drained your batteries are. You can avoid this problem by using encoders to monitor the motors actual speed and adjusting the speed control accordingly. Alternatively, you can use the same power system as the 3pi where the motor driver is supplied a constant 9 volts even as the battery voltage decreases. The boost regulator will make the hardware a little more complicated but it will mean you don’t need to write software that uses the encoders to keep the power to the motors steady as your battery voltage decreases.

As for the wireless, we do not have much experience with wireless communication. A member of the local LVBots robotics club modified his 3pi to be controlled wirelessly using two XBee modules. He connected the XBee modules to XBee adapter kits from Adafruit, and connected the RX/TX on the Adapter to the PD0/PD1 pins on the 3pi. He also wrote a bootloader so that he could wirelessly program his 3pi. SparkFun has this tutorial on wireless bootloading that might help you out.

Before you start making or buying twelve robots, I suggest you start with just one robot and see if you can get it to do what you want.

Does this answer your questions? If not feel free to ask more questions.

- Ryan

Ryan, thanks for detailed information.

I have ordered everything you mentioned (1J22122), I am excited to start, waiting for shipment :slight_smile:


You’re welcome. Feel free to ask here if you have any questions as you proceed.

- Ryan