This is the Revision A version of the PIC876Hub10 RoboBrick. The status of this project is that it has been replaced by the Revision B version.

PIC876Hub10 Robobrick (Revision A)

Table of Contents

This document is also available as a PDF document.

• 1. Introduction
• 2. Programming
• 3. Hardware
  • 3.1 Circuit Schematic
  • 3.2 Printed Circuit Board
• 4. Software
• 5. Issues

1. Introduction

The PIC876Hub10 RoboBrick is a master RoboBrick that can control up to N slave RoboBricks. It uses a PIC16F876 microcontroller from MicroChip^®. One of the hub ports can be connected to a communications RoboBrick to provide the ability to talk to the development platform.

There is a three terminal connector, one for ground and the other two for power. One power connector is connected to a standard 3-terimal 5 volt regulator to provide 5 volts to the slave RoboBricks. The other power regulator is only sensed for voltage level. The microcontroller has a built in analog to digital converter that allows it to sense the power level on both power terminals. When the power goes below a preset level, the robot platform can choose to enter a `hungry' behavior mode.

2. Programming

There is no programming specification for the PIC876Hub10 RoboBrick yet.

3. Hardware

The hardware consists of a circuit schematic and a printed circuit board.

3.1 Circuit Schematic

The schematic for the PIC876Hub10 RoboBrick is shown below:

The parts list kept in a separate file -- pic876hub10.ptl.

3.2 Printed Circuit Board

The printed circuit board files are listed below:

pic876hub10_back.png

The solder side layer.

pic876hub10_front.png

The component side layer.

pic876hub10_artwork.png

The artwork layer.

pic876hub10.gbl

The RS-274X "Gerber" back (solder side) layer.

pic876hub10.gtl

The RS-274X "Gerber" top (component side) layer.

pic876hub10.gal

The RS-274X "Gerber" artwork layer.

pic876hub10.drl

The "Excellon" NC drill file.

pic876hub10.tol

The "Excellon" tool rack file.

4. Software

There is no software for this RoboBrick yet.

5. Issues

The following fabrication issues came up:

• The holes for N1-N10 (size 3) are too large and should be made smaller (size 2).
• Label the components in the upper right corner better.
• Think about making the holes for SW1 (size 4) a bit larger (size 5).
• The fuse is too long, make it .10 inches or .15 inches shorter.
• Think about rearranging the switch to be a little higher up to get further away from the heat sink on VR1.
• Look around for an alternative processor the has reprogrammable flash. They should be starting to arrive on the scene.
• Put a plus sign next to the appropriate terminal of D1.
• Put a plus sign next to the appropriate terminal of D2.
• Put a 1 next to the appropriate terminal of U2.
• Look for another more PCB friendly power switch.
• Look for a better push button.
• Put a plus sign next to the appropriate terminal of C1.
• Try to find room for another terminal on N1 and two resistors to build a second battery voltage divider.
• Think about adding a heart beat LED.
• Move U2 down .05 inches so it does not interfere with N10.
• The crystal interfers with N10.
• The reset button may not be needed.