Simple Touch Controlled Musical Door Bell Circuit

Forget the boring ding dong bell!

This circuit shows how to build a doorbell that plays a little tune instead.

Just touch a button and it will ring out a melody tone one can choose for itself.

This is a fun way to add some personality to the doorway.

Circuit Working:

Parts List:

This circuit uses touch control to operate a musical bell by generating a musical tone when the particular touch pad is touched.

It produces enough sound because of  its two AA batteries.

The circuit makes use of the commonly found IC UM 3481 often found in musical circuits and its built-in components which include oscillators, frequency dividers, modulators, run off control, a ROM with 512 musical notes and preamplifiers.

Only a few extra parts are needed for designing the circuit.

The integrated oscillators timing components are C1 and R1.

Transistor Q1 is used to power the speakers and transistor Q2s base serves as a touch pad to activate the melodic bells.

Formula:

We can use the IC UM3481 to build a touch controlled melodic doorbell by following a simple circuit design that consists of the IC, a touch sensor and few additional parts.

One can use a specialized touch sensor module or a simple RC circuit to achieve touch control.

Below are the basic formula for touch control:

τ = R * C

where,

• R is the resistance and C is the capacitance.

Timing:

To assure the dependable touch input triggering to the UM3481 IC one can adjust the values of R and C.

With the help of the UM3481 melody generator IC and with these instructions one can successfully build a touch controlled musical doorbell.

See the datasheet for specific pin design and melody choices.

Modify the circuit design and component parts to fit the needs of ones project and the melodies it requires.

How To Build:

To build the Simple Touch Controlled Musical Door Bell Circuit one need to follow the below mentioned steps:

Identify Components:

• One should check that all the components mentioned in the circuit diagram are present

IC UM 3481 Placement:

• Place the IC UM 3481 on the breadboard or PCB for ensure its proper position

Connect Power Supply:

• Connect the positive terminal of the AA cells to the Vcc pin of the IC and the negative terminal connect to the ground pin.

Connect Timing Components:

• Connect the resistor R1 and capacitor C1 to the correct pins of the IC usually pins related to timing functions.
• Refer to the datasheet of IC UM 3481 for the exact pin connections.

Connect Loudspeaker:

• Connect one terminal of the loudspeaker to the collector of transistor Q1 and the other terminal to the positive terminal of the power supply.
• Connect the emitter of Q1 to the ground .

Connect Transistors:

• Connect the base of transistor Q1 to the output pin of the IC responsible for generating the musical tone.
• Connect the base of transistor Q2 to the touch pad.

Final Connections:

• Check twice for all connections and also check whether there are no loose connections or short circuits.

Test the Circuit:

• Power the circuit by inserting the AA cells.
• When the touch pad is touched the musical bell should produce a sound.
• Adjustments to the sensitivity is made by changing the value of the resistor or capacitor connected to the base of transistor Q2.

Note:

• When dealing with electrical components be careful at all times and be sure that the connections and polarity are correct to avoid harm to the circuit or the components.

Conclusion:

Using ones favorite songs or melodies users can modify their doorbell experience with the touch controlled musical doorbell circuit which provides a stunning and modified alternative to traditional doorbells.

Any entry to a house or place of business can benefit from its elegant and unique touch.

References:

Datasheet UM3481