I'm planning to use a long range USB RFID reader (12V) like this with Pi. As Pi USB can supply only 5V, how can I connect it to Pi USB, if it is not external powered..??

  • 1
    The device you linked to is not a USB RFID reader. According to the specs the interface is "Wiegand 26/34,RS485/232"
    – Craig
    Oct 14 '14 at 16:49
  • Ya,sorry, my mistake...I mean to use an USB powered but gives a reading range like the above mentioned reader, around 1 meter.
    – Ron Thomas
    Oct 15 '14 at 12:48

A switching step-up converter could be used to provide a higher voltage (12V) from a given lower voltage (5V). Be sure that the 5V power supply of the RPi can provide high enough a current though to drive that additional load.

ElectricalEngineering.SE might however be better suited to help on that matter and recommend a circuitry for that need. If you just want to buy some ready-to-use gagdet look out for "DC DC Step Up Converter".

  • Thanks for that step up converters... Pi B+ gives 1.2A for USBs (distributed over 4 ports), so I suppose that will be good enough.
    – Ron Thomas
    Oct 15 '14 at 12:52

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