Remote control for toy car

Remote ContRol foR toy CaR

 -Rohan B. ReBello

RECEIVER CIRCUIT  

     Remote ContRol foR toy CaR s.c. dwivedi Make any battery-operated toy car remote-controlled using  this circuit. The circuit, consisting of an infrared transmitter-receiver pair, uses IR beam transmission  to switch the toy car ‘on’ or ‘off.’ To  operate the toy car, you need to holdthe transmitter in your hand, keeping  it pointed at the toy car which has the  receiver fitted inside, and simply press  a switch provided on the transmitter. The transmitter works off 9V DC while the receiver needs 6V DC.  while the receiver needs 6V DC.  Fig. 1 shows the transmitter circuit.  It is built around two BC558 transistors  (T1 and T2), three BC548 transistors  (T3, T4 and T5), IR LED1 and a few  discrete components.  Fig. 2 shows the receiver circuit.  It is built around IR receiver module  TSOP1738, two BC548 transistors (T6  and T7) and a few discrete components.  In the transmitter circuit, there are  two astable multivibrators. The first, built around transistors T1 and T2, produces a frequency of about 1.2 kHz.  The second, built around transistors  T3 and T4, produces about 38 kHz. IR  LED1 is used to transmit the 38kHz  frequency.  In the receiver circuit, TSOP1738 receives the IR signal transmitted by  IR LED1 of the transmitter circuit. The  output of TSOP1738 is fed to transistorT6 via diode D1. The amplified signal  is further given to relay-driver transistor T7. Relay RL1 energises to control  the toy car. Working of the circuit is simple.  Initially, when no IR beam is falling on sensor TSOP1738, the relay  remains de-energised and the toy  c a r   d o e s n ’ t   m o v e .   W h e n   s w i t c h S1 is pressed, the IR beam falls on  TSOP1738 and its output goes low.  Transistor T6 cuts off and transistor T7 conducts to energise relay RL1 and  move the toy car.  Assemble both the circuits on separate PCBs. Enclose the transmitter PCB  in a suitable cabinet, with IR LED1  affixed on the front side and switch S1  on the top of the cabinet. Keep the 9V  battery inside the cabinet.  Enclose the receiver PCB inside  the toy car, with TSOP1738 fitted such  that the transmitted IR beam directly  falls on it. Fix switch S2 on the body of the car and the relay inside the car.  Use a 6V battery to operate the toy car receiver unit.

TRANSMITTER CIRCUIT