ORA-2 accessory decoder

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ORA-2 = Open Rocrail Accessory decoder for use with many systems including ORD-1

ORA-2 is a multi purpose accessory decoder, code compatible with ORA-1 and Opendecoder. It is designed to be small, but yet built with through-hole components.

ORA-2 is a based on and code compatible with Opendecoder (OpenDecoder Hardware 1). Many thanks to Wolfgang Kufer and his OpenDCC project.

• Full Rocrail support
• Compatible with ORD-1
• 8 outputs ( 4 turnouts )
• 68x50mm PCB
• NMRA-DCC compatible
• Use combined power+data (track voltage) or separate power (AC) + data (low voltage DCC or track voltage DCC)
• For solenoids and LED/lamps
• 0,5A or 1,0A current for solenoid drivers

Schematics and PCB artwork was created with KiCad, an Open Source (GPL) PCB Suite. Complete CAD files are accessible through RocRail Subversion repository.

No electrical changes since v1.0. SW1 footprint corrected.

• Kicad files:
  • ora-2.zip
• Schematics
  • ora-2.pdf
• PCB Layout:
  • ora-2-Copper.pdf
  • ora-2-SilkSCmp.pdf
• Part list:
  • ora-2.lst
• Errata: None
• Status: Tested. Works fine. D3 (bridge) placement and mounting hole placement can be improved. F1 footprint can be improved.

• Resistors: For best result, use 1%, 1/4W, metal film resistors.
• Multifuse: This is a safety device, a self resetting fuse, a PTC resistor, to protect your equipment. Preferred type is a 0,9A hold current type, like BOURNS MF-R090.
• Smoothing capacitors: 470uF is not critical. 220uF-1000uF 50V-63V 5mm leg spacing will do fine. 4,7uF is not critical, any value 1-10uF >16V 2,5mm leg spacing will do fine
• Rectifier bridge: The bridge must sustain minimum 1,5A.
• Crystal: 10MHz for parallel capacitance. Can optionally be fixated/grounded with a spare component leg soldered to case.

Please see ORA-1 and Opendecoder for detailed descriptions of programming and usage.