I have got problem sometime, when receiver with 433 rx but sometime turn on output without transmitter not send by serout, I made handheld box after bread board has tested first ok.
serin 2,n300,("a"),b1, sometime has error turn on then off, i checked make sure circuit have capacitor 0.1uf, L4949 5 volts all its ok, but bread board wasn't a problem with serin never error turn on when transmitter not on by serout. Maybe need to put something like filter capacitor etc, bread board had 7805 regulated no problem.
serin 2,n300,("a"),b1, sometime has error turn on then off, i checked make sure circuit have capacitor 0.1uf, L4949 5 volts all its ok, but bread board wasn't a problem with serin never error turn on when transmitter not on by serout. Maybe need to put something like filter capacitor etc, bread board had 7805 regulated no problem.