Power RFID Reader via GPIO Ports of Electron?


#1

Hi there

I am using the awesome Particle Electron with a NFC Reader from Elechouse ( link ).
Now I have it connected via SPI and the regular 3.3V power port. But I would like to cut the current to it while the elctron sleeps (not sure how much power it uses when not reading but even the LED on the reader kind of annoys me :wink: ).
Could I power this reader via a GPIO Port somehow maybe so I can turn it on and off with WriteDigital?

Thanks a lot in advance! :slight_smile:

  • Tiju

#2

GPIO ports are IO ports, they really shouldnโ€™t power anything,so put a little FET like a VN10 between your Reader and 3V3 and connect the gate to a GPIO to power it on/off.


#3

@Tiju, you may also want to add an external pull-down resistor (10K to 47K) to the FET gate to keep it OFF when the Electron is in deep sleep. :wink:


#4

thank you @Viscacha & @peekay123
would this work with a VN10LP ?
If I understand correctly itโ€™d be like this:
GPIO -------------------------------|-- FET Gate XX Source <-> 3.3V XX FET Drain <-> VIN on NFC Reader
GND โ€“ pull-down-resistor ----|

Thank you! :slight_smile:


#5

would this work? :slight_smile:
N-Channel:
N-Channel @ falstad simulator
P-Channel:
P-Channel @ falstad simulator


#6

@Tiju, it didnโ€™t work because you are using a P-MOSFET instead of an N-MOSFET. I should have specified! What you have will work. For the P_MOSFET, the pull-up is not required since the 3.3v gate voltage is provided by the Photon GPIO pin. Either way is good.