This circuit was obtained in a 1989 publication and is quite simple to assemble, but critical in terms of operation. It is a sound transmitter and a receiver. The receiver detects when the transmitter moves (or the receiver moves) by changing the signal received by the Doppler Effect and thereby triggering the relay. The circuit operates at 40 kHz, thus requiring the emitting transducer and a receiver for this frequency.
| Clique na imagem para ampliar |
