In the past, RC transmitters were expensive units costing hundreds of dollars even on the low end. They are now available fairly cheaply, and you can even build them yourself. [Phytion] That's exactly what I did.
This design is not based on modern microcontrollers, nor does it rely on WiFi or Bluetooth connectivity. Instead, it's a little more old school. It is built using the HT12E parallel/serial encoder chip and his HT12D decoder chip for the receiver. For the controllers, I use one set of HT12E for the transmitter and one set of HT12D for the receiver. These accept input from a pair of analog joysticks and encode it as serial data. However, this design essentially just functions as a digital joystick. The HT12E inputs the data from the HT12E into an STX882 module that transmits at 433 MHz. Another he STX882 module receives this signal and for decoding he passes the signal through the HT12D.
On the receiving end, four outputs can be turned on or off depending on whether you push one joystick up, down, left, or right. You can do the same for four more outputs using the channel selection switch. The second joystick mirrors the operation of the first joystick. This is intended to make it easier to control things like RC cars by allowing you to tilt one stick forward and backward and the other left and right.
You don't see designs like this very often anymore. Realistically, it is possible to extract far more functionality from a design based on an ESP32 or similar wireless-enabled chip. However, it doesn't require any complicated handshakes and powers on instantly, which is a nice bonus. Plus, it's always interesting to see alternative designs tried out in practice. Video after the break.