Hardware Design 2

BrickPi AloneBrickPi is has its roots in Arduino.  At the center of the BrickPi is an Atmega328, programmed with Arduino an Arduino bootloader and firmware (which you can read more about here).

Overview

At the heart of the BrickPi is are two Arduinos.

  • Clock: The microprocessor is run on a 16MHZ clock.
  • Serial Line:  The serial line runs from the Raspberry Pi to the two Arduino chips.
  • Power:  Power is supplied to the entire unit with a 9V battery.  The 9V supplies drive power to the motors directly.  The 9V battery is regulated to 5V depending on the model: Advanced power uses a step down regulator, and the basic model uses a switching device voltage regulator.  The 5V rail supplies power to the BrickPi microcontroller, Raspberry Pi, sensor ports, and indicator LEDs.
  • Motors:  Motors are controlled by the Texas Instruments SN754410.  PWM control is supplied by the Arduino, and power is provided directly by the 9V battery.
  • Sensors:  Sensors are powered off the 5V regulator.  These can be normal digital sensors or analog sensors, which are read by the micro controller.
  • Ports:  All Ports (sensor and motor) are the Dexter Industries NXT Sockets for LEGO MINDSTORMS NXT.  You can find them here.

BrickPi

Schematic

The schematic for the current design can be found here.

It can also be found, along with the Eagle Schematic and Board files, on our Github Page here.

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2 thoughts on “Hardware Design

  1. peterB May 19, 2013 4:37 am

    I like the idea and I’m signing up for the Kick Start. However, I would like to make a couple of suggestions;
    1) replace the 7805 with a LOW DROP OUT voltage regulator so you could use a range of voltage sources even down to just 6 volts.
    2) more of an observation, but you will need more power then what the 9V battery can provide. The 9V battery has low mAh capacity (typically around 500 mAh). Using the low dropout regulator you will be able to power from say a 7.2 LiPoly battery

    The Raspberry PI draws about 500mA by itself. Arduino + LEDS about 50 mAh.
    Currents draw of LEGO NXT motors about an Amp from memory.

    “Scotty, I need more power” – Cpt Kirk, Star Trek.
    “Master, I need more power” – Brick Pi after using a 9V battery for a very short time.

  2. Brian Hanifin May 31, 2013 4:28 pm

    peterB, One way to lower the power requirements is to use a Raspberry Pi Model A. I don’t recall the numbers, but I believe the Model A uses like 1/3rd the power of a Model B. Yes you get less memory, but don’t need Ethernet for a robot and your battery should last longer.

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