Won’t it be nice to have music playing in the background all the while when you take a shower? This simple circuit does the same. It plays different tunes repeatedly for as long as your shower is turned on. The music starts as soon as water comes out of the shower. The music stops when you turn the shower ‘off’ and water stops coming out of it.
Fig. 1 shows the circuit of the musical water shower. It comprises transistors T1 and T2 which form a complementary amplifier pair, transistor T3 acting as a switch and a 12-tone melody generator IC M3482. The M3482 is a mask-ROM-programmed IC designed to play melodies according to the programmed data. Its inbuilt preamplifier provides a simple interface to the driver circuit formed by transistors T4 and T5. The IC can be replaced with other UM348xx series, WR630173 or WE4822 melody generator ICs.
The melody section receives power supply through the conduction of transistor T3 when the shower is turned on.
The overhead shower unit is fitted with two insulated copper cables AD and BC as shown in Fig. 2. Insulation of a part of the cable AD (marked A’D’) is removed. Cable AD is firmly fixed and routed along the body of shower without any shorting of the bare part with the shower body. The bare part should stretch such that the shower water falls on it when running. One end of copper cable BC is soldered to the body of shower at C. It is wound around the neck to secure it firmly. Thus the cable ends at A and B are available for connection as sensor input to the circuit of Fig. 1. Now when you open the shower tap, water falls on the bare copper wire A’D’ which makes electrical contact with the cable BC through the body of the shower which is also in contact with running water. The points A and B of cable on the shower unit are connected as sensor input to the circuit of Fig. 1. This makes the power available to the base of transistor T1, which now conducts. This makes transistors T2 and T3 conduct. Thus the power supply is available for the melody circuit (Fig. 1).
The melody generator IC is programmed to produce twelve different tunes repeatedly until the shower water is running and transistors T1, T2 and T3 are conducting. The volume of melody generator tunes can be control-led through preset VR1.
When the shower is turned off, both transistors T1 and T2 cut off and a high voltage develops at the base of pnp transistor T3. Thus transistor T3 stops conducting. This, in turn, cuts off the power supply to the melody generator circuit, which stops generating musical tunes. Since the circuit consumes virtually no power when the shower is turned off, the battery lasts long.
Assemble the circuit on a general- purpose PCB and enclose it in a plastic case with LED1 and switch S1 accessible from outside. Take the sensor wires and connect to the wires on shower at A and B ends.
