This is a unique channel relay that works with 5v and a positive signal.
2 x 1k SMD 805 resistors;
1 x SMD Diode that suport more than 5v of reverse voltage;
1 x 5v relay;
1 NPN sot23 transistor similar of BC548/337;
1 Optocoupler TLP621 or PC817;
1 double face PCB with 50mm x 23mm