I'm trying to build a custom wireless doorbell, similar to those you can buy everywhere (example). I just need to emit a single signal and receive it elsewhere, to make a buzzer sound.
I've already got all the components except the RF device needed for communication. My requirements are: ~30 mts. distance, maybe passing through one indoor wall and not to be too expensive (you can buy one of those complete doorbells for less than $20). Ideally, I would trigger this module using a microcontroller operating at 3.3 or 5 volts, and as I'd hand assemble this, SMT components should be avoided.