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I'd like to use MX-FS-03V 433MHz transmitter together with a Raspberry Pi (RPi). The Raspberry Pi's outputs have 3.3V, but the MX-FS-03V operates on 3.5-12V (the higher the voltage the higher the transmission distance).

In my understanding, when connecting the MX-FS-03V's VCC to 12V, the DATA input pin must use the same voltage. Is this correct?

The RPi provides 3.3V and 5V, but no 12V. What would be the most simple way to let the MX-FS-03V operate on 12V?

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  • \$\begingroup\$ Use a BJT common emitter amplifier. \$\endgroup\$
    – Andy aka
    Commented Mar 6, 2015 at 10:02

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If this circuit diagram for the transmitter is correct, you don't need to level-shift your output:

enter image description here

The TXD pin is the input to the base of an NPN transistor, so all that's necessary is enough voltage to turn on the transistor. Your 3.3v output from the RPi should work fine.

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  • \$\begingroup\$ Thanks for pointing that out! What would be the best way to get 12V from the RPi? \$\endgroup\$
    – squarebrackets
    Commented Mar 6, 2015 at 10:19
  • \$\begingroup\$ @squarebracket You might want to have a look at boost convertors or charge pumps. \$\endgroup\$
    – tangrs
    Commented Mar 6, 2015 at 10:42
  • \$\begingroup\$ @squarebracket The best way would be to use 12V as your main supply and regulate it down to power the RPi. \$\endgroup\$
    – Nick Johnson
    Commented Mar 6, 2015 at 10:52
  • \$\begingroup\$ Would be a RNM-0512S sufficient (5V to 12V, max. 83 mA)? \$\endgroup\$
    – squarebrackets
    Commented Mar 6, 2015 at 10:54
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    \$\begingroup\$ @squarebracket Then that boost regulator should be up to it if your 5v power source can supply enough current (eg, not the RPi's USB plug!). Converting down for the RPi is still probably a better idea. \$\endgroup\$
    – Nick Johnson
    Commented Mar 6, 2015 at 11:25

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