Raspberry Pi - Revision 2 DIY Add-On Board

On the Raspberry Pi, there are several connections which can be used for expansion:

    1,  The Rpi GPIO (General Purpose Input/Output) pins are exposed, that means that expansion
          boards are able to talk directly to the CPU.

     2, The DSI connector will allow low-level interfacing with LCDs and other displays.

     3,  The CSI connector will allow camera modules to be added in future.

Raspberry Pi - Revision 2  DIY Add-On Board

Features:

1.         5V/3A power-supply
2.         buffered interface to GPIO pins
3.         4 button switch
4.         3 LED [include 1 hardware PWM] - external connectors also available
5.         1 Relay
6.         5V logic Level UART interface
7.         16x2 LCD [74hc595 based]  with back light control option
8.         SPI ADC MCP3008
9.         DS1307 with battery backup holder
10.         24C032 EEPROM
11.         PCF8591 DAC_ADC
12.         i2c external connector [3.3v to 5V logic converter included]

block diagram representation

LM2587 Buck regulator  : 5V/3A power supply

3.3v to 5v level shifter  : ic74HCT125   -single direction

3.3v to 5v level shifter  for i2c  : MOSFET 2N7000 based    -bi directional

24c032 :eeprom

battery:  3V RTC backup battery

DS1307 : i2c based RTC chip

PCF8591: i2c based ADC-DAC chip

4 switch: user input button switches

MCP3008:  SPI based 10-bit Analog-to-Digital Converter

74HC595:  3 wire serial LCD interface

16X2 LCD:    16 character x 2 line  monochrome LCD  [serial interface -74hc595]

LED 1-3 : LED output 3 color LED  [include h/w PWM pin  ]

RELAY:   for  heavy   load application

note:

Raspberry Pi single side DIY add-on PCB with 5V/3A buck regulator power supply  board  designed for   Raspberry Pi Revision 2

circuit diagram list

1.     gpio relay led connection circuit diagram
2.     gpio button switch interface circuit diagram
3.     add-on board and raspberry pi powersupply  circuit diagram
4.     i2c interface circuit with ds1307 RTC and EEPROM  circuit diagram
5.     LCD and MCP 3008 interface diagram.

•     PCB layout : single side glass epoxy PCB
•     schematic and PCB tool : proteus  7.10  [3d view support]
•     hand soldering

add-on board with raspberry pi  - photos

i2c device listing  output

commands for i2c device listing
http://learn.adafruit.com/adafruits-raspberry-pi-lesson-4-gpio-setup/configuring-i2c

1, sudo nano /etc/modules

2, and add these two lines to the end of the file:
     i2c-bcm2708
     i2c-dev

3, sudo apt-get install i2c-tools

4, sudo nano /etc/modprobe.d/raspi-blacklist.conf

  If you do not have this file then there is nothing to do, however, if you do have this file, you need to edit it and comment out the lines below:

blacklist spi-bcm2708
blacklist i2c-bcm2708

.. by putting a # in front of them.

5, sudo i2cdetect -y 1  

1.     LED blink
2.     switch -LED toggle
3.     Relay ON/OFF
4.     PCF8591 i2c DAC-ADC test
5.     Hardware PWM control [LED and PCF8591]
6.     74hc595  16x2 LCD with back light control
7.     3 webservers on single raspberry pi  [   Nginx , apache 2, apache tomcat ]

true size pdf  image

1.     PCB bottom layer
2.     PCB component layout

• www.raspberrypi.org/‎
• www.wiringpi.com/‎
• https://projects.drogon.net/raspberry-pi/wiringpi/
• www.apache.org/‎
• www.tomcat.apache.org
• www.nginx.org
• http://www.learn2crack.com/2013/10/setup-nginx-web...
• http://www.cyberciti.biz/faq/howto-linux-unix-crea...