I used an Eachine AIO F3 brushed flight controller on my Syma x5c, this flight controller has a Betaflight OSD built in. It even comes with a beeper.
https://www.banggood.com/Eachine-AIOF3_BRUSHED-Flight-Control-Board-Built-in-OSD-FrskyFlyskyDSM2DSMX-Receiver-Betaflight-p-1107427.html?p=3A030685815520141160
https://www.banggood.com/Jumper-T8SG-Multi-Protocol-2_4G-10CH-Compact-Transmitter-for-Flysky-Frsky-DSM2-Walkera-Devo-Futaba-p-1189811.html?p=3A030685815520141160
https://www.banggood.com/Eachine-ATX03-Mini-5_8G-72CH-025mW50mw200mW-Switchable-FPV-Transmitter-w-Audio-p-1141121.html?p=3A030685815520141160
https://www.banggood.com/600TVL-8_0MP-14-2_8mm-CMOS-FPV-170-Degree-Wide-Anlge-Lens-Camera-PALNTSC-p-984345.html?p=3A030685815520141160
