Version 1 of the POE (Power over Ethernet) SNARC+

SNARC+ is a board developed by Luke “Hovo” Hovington on the idea from Lemmings original SNARC, the idea behind this iteration is the ability to power the board from a POE source thus allowing the battery backup to be in one location for all the RFID systems.

Though this is the case there has been allowance for power to be applied directly, the board will choose this source of power over the power coming from the POE.

The on-board functions of Version 2 are:

ATMega 328 Micro-controller with 32KB Flash, 2KB SRAM and 512B EEPROM. Power Over Ethernet This allows the user to place power down the ethernet cable, it supports a variety of standards like 802.3af Flash Chip The AT45DB is a external flash chip, the one currently on the board has 2Mb of space available allowing the user to store information that doesn't change that often like Mac address, Ip address and user cards for example, this allows for easy upgrade of software as these variables are stored externally to the CPU Flash and EEPROM. As this chip is only 3V3 tolerant on it's I/O, buffer chips have been added to handle the voltage conversion.

  • D10 - Chip Select
  • D11 (MOSI) - MOSI
  • D12 (MISO) - MISO
  • D13 (SCK) - SCK

Ethernet Module. This module uses the newer W5200 chip from Wiznet to comunicate to servers and the world. Please be aware you will need to update the library.

  • D2 (Int0) -Interrupt Pin
  • D4 - Chip Select
  • D11 (MOSI) - MOSI
  • D12 (MISO) - MISO
  • D13 (SCK) - SCK

Relay Output This allows for the output to be constantly powered without the drain of having a MOSFET constantly on, there are 3 outputs labelled NO/GND/NC (Normally Open, Common Ground, Normally Closed).

  • D8 - Relay Switch

Status LED's. There are three Status LED's on the board. Red, Green and Orange. These also have a screw terminal so you place the led's off the board if desired. The resistor can be replaced with a 0 ohm and remove the LED to turn these ports into general usable I/O.

  • D7 - Led 1
  • D6 - Led 2
  • D5 - Led 3

E-Stop header. This is for using the board in an access control scenario like a exit button. It is connected to one of the two interrupt pins on the ATMega to allow it to be used to interrupt other operations. There is a pull down resistor on this terminal this could be used in two ways, have this pin a constantly high through a NC switch. Or Low through a NO switch, the choice is yours.

  • D3 (Int1) - E-Stop or Exit button

ICSP header. This can be used to program the board and is used to load the Arduino bootloader on to the board at manufacturing time. This can also be used to access the SPI bus, Pin1 is marked with a small “1” on the board. FTDI header. Again this is used as a programming interface. Standard FTDI pinout, pin 1 is marked with a small 1 on the board. GPIO There is a few spare pins available or could be repurposed. Plus all the Analog pins just a bit further in.

  • The first header has (These are a screw terminal only connection)
  1. 5V
  2. E-Stop - D3 - Interrupt 1
  3. GND
  4. PIEZO - D9
  5. GND
  6. LED1 - D7
  7. LED2 - D6
  8. LED3 - D5
  • The second header has all the analog pins (Screw terminal or header could be installed)
  1. 5V
  2. A0
  3. A1
  4. A2
  5. A3
  6. A4
  7. A5
  8. GND

Reset button. This should be pretty self explanatory, this will reset the ATMega and the Wiz820io module at the same time.

  • projects/snarcplus
  • Last modified: 3 months ago
  • (external edit)