Electronic Smell (ART476E)

The idea behind this circuit is to show that the "smell" effects of Professor Ventura's Multimedia Theater story can be realized in practice (see Prof. Ventura on the site) The circuit consists of a small timer that triggers a relay at regular intervals for a few seconds, long enough to heat a wire resistor around which there is a wick that remains wet with aromatic essence.

Thus, in the activation, the essence evaporates spreading its aroma by the environment. The drive ranges are set at P1 and R2 determines the heating time of the wire resistor.

The base of the circuit is an astável with the 555 that drives a relay through a transistor. In figure 1 we have the complete diagram of the apparatus.

Figure 1 - Diagram of the perfumer

The printed circuit board for the assembly is given in figure 2.

Figure 2 - Printed circuit board for mounting

On assembly, note the position of the integrated circuit and transistor. The transformer has 12 + 12 V secondary with currents between 500 mA and 800 mA and the diodes admit equivalent.

The resistors are 1/8 W with any tolerance except X1 that has 10k x 10W if the network is 110V and 22k x 10W if the network is 220V, being the type of wire. If heating is insufficient for good evaporation, try 5 W resistors.

The one wick of fabric is wrapped around the resistor and has its tip threaded into a jar with essence. Never use essences that contain alcohol and can become inflamed.