Tuesday, March 8, 2016

Example of working robot from my desktop

When I use the robot, I connect using SSH. I can also see live camera feed from the webcam. My desktop looks like this:



The window on the left is the camera feed. The window on the right my SSH session on Mac Terminal. Using SSH, I am the Raspberry Pi from my laptop. I can send commands to move the robot, or even write or adapt programs in case the robot gets stuck.

I will post later about exactly how to program the robot using SSH.

Monday, March 7, 2016

Batteries / Battery Power

When I first started out I used the normal Raspberry Pi power supply:




 but as I quickly found out, it is not enough voltage to turn the LEGO Mindstorms motors:




Then I figured out BrickPi had me covered:




That worked but I could still do better (by not using disposable batteries and having the battery last longer):





This is a remote-controlled car battery with a homemade adapter (the construction of the adapter will be in another post). The most important things were:
  • the voltage is not above 12v (this would overload the Raspberry Pi) or below 5v (this would cause the Raspberry Pi to restart if the motors used too much power).
  • the polarity must be correct (the inside of the connector is positive).
  • measure the actual voltage using a multimeter (the battery marked 8.4v actually puts out over 10v).



Getting Started

My name is Leo and I'm in seventh grade.

My robot is now almost completed. Periodically, I will post the steps that I took to build it.

Starting with the hardware: This is my Raspberry Pi with the BrickPi attached in the case that comes with the BrickPi.


I duct-taped an old webcam to the top. It happens to be from Logitech but most webcams will do:


I started out using 8xAA batteries and the BrickPi battery holder but I have since upgraded to a 3000mAh NiMH 8.4v battery that I salvaged from a radio-controlled car. I will do a separate post about power and batteries.

Right now, the robot looks like this:



Saturday, March 5, 2016

The worldwide BrickPi robot challenge

The challenge:

Build a robot that can function, be re-programmed, and be controlled from a computer no matter where the robot or computer is located.

(as long as each one is connected to the internet)

The hardware:
  • Raspberry Pi
  • BrickPi shield
  • LEGO Mindstorms motors and LEGO parts
  • leftover digital webcam
  • battery pack (either 8xAA or repurposed from r/c car)
  • USB wifi adapter
The software:
  • Dexter Industries' Raspbian for Robots
  • Python
  • motion (for the webcam)
  • OpenVPN (to connect to the internet using Amazon Web Services)