Motor Boat Sound Generator Circuit

Think like small motorboat comes inside our room very easy.

This Motor Boat Sound Generator Circuit is an electric thing enough for this design.

No need of water, no need of big wooden frame or big motor join.

What is a Motor Boat Sound Generator Circuit:

Motor boat sound generator circuit is electric circuit that make sound like motor boat engine.

It is having many small electric parts that work together to make ‘phut phut’ sound which is same like real motor boat moving.

This circuit is used in toy boats, fun projects and for time pass because it make sound very close to real one.

Circuit Working:

Parts List:

This small device make motorboat sound when moving.

One knob is there to change the sound like engine start and throttle up-down.

Good thing is whole system fits inside small box.

On top it is having easy buttons to use.

Buttons name are: idling, throttle, start and ON/OFF.

After setting speaker volume as we like connect output wire to amplifier or radio input.

When we press start button for short time it start making “phut phut” sound like real engine starting.

Do this one or two times to feel like engine warming up.

When we turn ON/OFF switch ON, slow “phut phut” sound start like engine idling.

Then turn the knob slowly to make “phut phut” go faster like giving throttle.

Main working part inside is a free running multivibrator.

That knob which is the potentiometer control speed of “phut phut” by changing multivibrators frequency.

When the press start one capacitor charges up with power and this gives short power to device for few seconds which makes “phut phut” sound slowly and fade out like engine starting.

When ON/OFF is ON full power goes inside and device keep making slow “phut phut” sound like engine running.

Turn knob more then sound will go faster and like engine going faster.

Sound will become louder when resistance goes down.

To stop boat engine sound turn OFF using ON/OFF button in which “phut phut” slowly stops.

One capacitor is in output block DC, but allow sound pulses to pass.

All switch connections we can see in the circuit diagram above.

Formula:

If we want to learn and make adjustable BJT astable circuits we can start with this formula:

f = 1 / (1.4 × ln(1 + R2 / R1) × C1)

here,

• f is the frequency of output signal in Hertz H.
• R1 and R2 are two resistors and these are connected to base of both BJTs and they control the speed of output signal.
• C1 is the capacitor which connects between base and collector of both BJTs.
• ln is natural log

Some important things:

This formula works when BJT is working in active mode.

Capacitor must charge and discharge fully in every cycle.

But in real circuit parts may not be perfect like BJT gain and value tolerance, so output frequency may not be 100% same as calculated.

We can change R1 and R2 to get different frequencies which gives flexibility.

This formula shows if R2/R1 ratio is higher then frequency will change.

How to Build:

To build a Motor Boat Sound Generator Circuit follow the below mentioned steps for connections and assembling:

Study the Circuit Diagram:

• Look at circuit diagram carefully and see where each part go and how wires are connected.

Note the Parts:

• Write down value of resistors, capacitors and other parts.

Collect the Parts:

• Take all parts we need same like in the circuit diagram.

Prepare the Board:

• If we use PCB put parts in right place as shown in circuit.
• Use diagram to guide, when soldering the parts on PCB.

Connect the Parts:

• Use small wires to join all parts together.
• Be careful with parts like capacitors and diodes as they have + and − sides which is the polarity.

Soldering:

• Solder all pins and wires properly.
• Be sure there is no short circuit and all joints are solid.

Controls and Potentiometer:

• Follow the circuit and connect ON/OFF switch, start button and potentiometer.
• These help change the engine sound like start or speed up.

Power Supply:

• Connect power in the correct place as shown in circuit.
• Check the voltage is right not too high or low.

Testing:

• Turn power ON and use multimeter to check voltage at different points.
• Press start button and turn knob like potentiometer to hear different boat engine sounds.

Tuning:

• Adjust the potentiometer slowly to get best engine sound.
• Try different settings until it sounds like real motorboat.

Important Tips:

• Check all connections and part values again to avoid mistakes.
• If anyone is new to electronics then better ask someone or check more information online.

Conclusion:

In this Motor Boat Sound Generator Circuit the ON/OFF switch, start button and potentiometer give user full control of engine sound.

We can make sound stop, idle or start up like real boat.

Final result is a fun and useful engine sound circuit which is often used by toy boat lovers or in sound effect projects to make it more real.

References:

Motorboating (electronics)

Sonogram of the sound produced by a motorboat