Read seller descriptions carefully if the disk is encased in a plastic housing just to make sure it is of the passive type. We need to control the pitch and so we need this “passive” type of piezo sounder.
If we disconnect power the disk goes back to normal, repeat this fast enough, on off on off etc., and the movements back and force of the disk (vibrations) cause a sound, the faster we switch the disk on and off the faster the vibrations and the higher the pitch. With the simpler types if you just add power you will hear nothing, when power is supplied the disk flexes (you wouldn’t notice it though as it’s too small an amount). These types are handy when all you want is a simple beep and no change in tone etc. If it’s item title includes the words “buzzer” then often it includes some electronic components to enable it to beep when power is supplied. It’s essential you buy a “passive” piezo sounder/speaker. Piezo Sounder or Piezo Buzzer – what’s the difference, which do I buy? Proper speakers draw too much current so cannot be directly connected to the Arduino (or just about any other processor either).Īn example of a Piezo speaker is shown below, they often come with black and red wires but they can be connected to any polarity – it makes no difference. These have terrible sound quality and generally aren’t very loud, so why use them? Well they are extremely cheap ($1,GBP1,1Euro for about 10 of them pre-wired) and take very little current to operate, meaning they can be directly connected to Arduino pins with no issues. Sound is no exception, so we need to add some sort of sound output device, which in the simplest case can be a piezo beeper. Whether this is a temperature sensor (see here, hereand here!) or a display (see here). So we have to add components to them to get them to do anything useful.
#Piezo sounder code
are embedded computers, they are designed to run code and control/read their input/output pins. It uses tone to play a variety of notes over a wide frequency range to test your sounder.Micro-controllers such as Arduino’s etc. There is a simple melody sketch I adapted from Sparkfun to test the piezo sound quality and loudness reposited here.
#Piezo sounder driver
This is a super-small breakout useful for evaluation of the settings of the sounder driver for particular packaging constraints as well as a source for sound indication that can be easily incorporated into many existing projects. For many devices, users appreciate both visual feedback from led indicators, tactile feedback from switches and haptic motors, as well as aural feedback from something like this small piezo sounder. Or simply use this breakout board as part of your application to provide sound indication for users. The proper sound level for your application (which depends on the location within the design case, the case materials, place on the body or proximity to people, etc) can be determined with this breakout board and then hardwired into your custom design. The sound frequency drive is supplied to DIN by a GPIO pin from the MCU via PWM (tone). It has provision for driving the piezo at 1x, 2x, and 3x the input voltage (up to 3V3, a common MCU voltage) with simple TTL input from two GPIOs of the MCU. This NJU72501 sounder driver is a small solution to the problem of using piezo sounders well. Piezo sounders offer surprisingly high-quality sound in a small package, but require higher voltages than are typically available on 3V3 development boards to sound loud enough to hear well. When the project is small, as in wearable/portable, there are not a lot of good options that don't dominate the project size.
Why did you make it?Īdding sound to a project is as easy as hooking up an 8-Ohm speaker to a PWM-capable GPIO pin (maybe with a current-limiting resistor!). Thus the sounder driver (maximum peak-to-peak drive +/-10 V in differential mode) and the sounder are well matched. The sounder operates between 0 and 10 kHz (midrange is 4 kHz) and at a maximum peak-to-peak voltage of +/- 12.5 V. I have included Murata's smallest (9 mm x 9 mm) PKMCS0909E4000 piezo sounder, but this can be left off the board if you want to use another piezo sounder. The board exposes all of the pins of the driver including VIN and GND for power, VOUT for the output of the boost converter, EN1 and EN2 to choose 0X, 1X, 2X, or 3X the input voltage (2.3 to 5.0V(1x/ 2x Mode), 2.3 to 3.4V(3x Mode)), and VO1 and VO2 to drive the piezo sounder either in single-ended mode (with VO1 connected to one piezo input and the other grounded) or differential mode (with both VO1 and VO2 connected to either input of the sounder). This is a small (0.7 " x 0.4 ") breakout board for New Japan Radio's NJU72501 piezo sounder driver.