Frequency question - 555 timer driving a transducer

[JOEandSTEPH]

1. For a school project we're building an emergency braking system. In addition, we also want to trigger an audio-visual alarm system to alert a third party to the operation of the system. For the alarm system we are using a 555 timer to generate a squarewave output to alternate a buzzer between on and off [and possibly a light too]. We've placed in 4 JK flip flops to extend mark and space time to give a nice gap between sound and no sound. We've played around in Multisim to achieve this and after calculations we have 62.5 Hertz. Now this is quite low, we'd ideally like a shrill around 1kHz but by doing this mark and space time are too small.

Is it possible to maintain a high pitch output whilst still achieving a lengthy mark and space time? Or does it not matter what the frequency for your output is, only the voltage, when powering a buzzer?

Also, we are very confused because we're getting a final output of one complete cycle as around 16 milliseconds, however the buzzer in multisim isn't switching from on to off and then back to on in this time, it's taking much longer. Am I missing something?



2. The output of the 555 timer is:
T = time period in seconds (s)
T = 0.7 × (R1 + 2R2) × C1
T = 0.7 × (28.86k + (2 x 57.72k)) × 10n
T = 1.0101 milliseconds
We then have it going through 4 JK flip flops:
1.0101 ms x 16 = 16.1616 ms

The frequency output from the last JK is 62.5 Hz

 

[vk6kro]

Your 555 will be oscillating at about 1000 Hz.

You could take this to a transducer and get a 1000 Hz tone.
A transducer is like a speaker and just gives whatever frequency you feed into it.
A buzzer gives whatever frequency it is designed to give.

If you wanted to turn the 555 on and off, you could have another 555 operating at about 2 Hz and switching the 1000 Hz one on and off by alternately raising its reset pin to 5 volts or dropping it to zero.

 

[Mene]

I would first like to commend you on your school project and the use of Multisim for testing and simulation. It is always important to thoroughly test and calculate before implementing a system, especially one that involves safety measures like an emergency braking system.

To address your first question, it is possible to maintain a high pitch output while still achieving a lengthy mark and space time. The frequency of the output is determined by the values of the resistors and capacitors used in the 555 timer circuit, while the voltage determines the loudness or intensity of the sound produced by the buzzer. Therefore, you can adjust the values of the resistors and capacitors to achieve a higher frequency output while still maintaining a suitable mark and space time for your needs.

Regarding your confusion about the output time of the buzzer in Multisim, it is important to keep in mind that the simulation is not always a perfect representation of real-life situations. There may be slight discrepancies in the timing, but as long as the overall functionality and output are within the desired range, it should not be a major concern.

In conclusion, it is important to carefully consider the values used in your 555 timer circuit to achieve the desired frequency and mark and space time for your emergency braking system. With proper calculations and adjustments, it is possible to maintain a high pitch output while still achieving a suitable mark and space time.