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### Topic: How can I make 26Khz square wave signal? (Read 2808 times)previous topic - next topic

#### fugally

##### Jun 20, 2013, 07:39 am
Hi.

I just bought start to use a arduino uno to control MZB1001 which is a small piezoelectric air blower. According to the the datasheet of this air blower, I need to make 10~20 Vpp with around 26 Khz square wave signal. Although they describe simple circuit to make this signal using LM7321MA, I cannot make it because of all of these recommended components are SMD type.. And I cannot control this blower when I make this circuit with usual type of resister (0.5W) and PN100, PN200 transitors..

So I am trying to generate square wave without extra components. When I checked the Arduino forum, I could find some posts about how to generate square wave, but most of them didn't work because of low voltage.

I want to solve this problem without buying extra components because I already spent too much time... Now I have just general type of resistor, capacitor and OPamp (LM358N, LM6484A1N).

Is anyone can help me to solve this problem?

Thanks,

PS) This is the datasheet of the MZB1001 micro air blower.

http://www.mouser.com/ds/2/281/MZB1001T ... 202918.pdf

#### larryd

#1
##### Jun 20, 2013, 08:30 amLast Edit: Jun 20, 2013, 08:35 am by LarryD Reason: 1
Edit, I guess you need a sine wave 10+ Vpp the suggestions below will not work.

You could use a 555 timer in a Astable configuration:
http://www.ohmslawcalculator.com/555_astable.php

You could use the Arduino and the tone() function.
Have the Arduino drive a NPN transistor with a 15 power supply.
No technical PMs.
If you need clarification, ask for help.

#### muddy

#2
##### Jun 20, 2013, 09:43 am
I just had a quick look at the website. I think you need a sine wave of 24 - 25KHz.

Anyways, here is how to create a square wave using only an opamp and discrete components: http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/square.html

For creating a sine wave, i recommend you use a 'Wien-bridge oscillator'. It is also built with opamps, capacitors and resistors.

#### dc42

#3
##### Jun 20, 2013, 01:35 pmLast Edit: Jun 20, 2013, 01:39 pm by dc42 Reason: 1
The device is resonant at 24-27kHz according to the datasheet, so a square wave drive through a small inductor should be OK. In fact page 17 shows a square wave drive.

Unfortunately, the datasheet does not appear to give any indication of the power consumption of the device, other than that the output transistors in the suggested circuit are specified as 500mA types. The NE555 is rated at 225mA, so it might be sufficient at lower drive voltages. My choice would be to generate a 26kHz square wave using one of the Arduino counter/timers, and use a MCP1407 mosfet driver chip to amplify the output and drive the device at up to 18Vp-p. Connect a small inductor and a 1uF capacitor in series between the MCP1407 output and the fan, and a resistor (e.g. 100k) in parallel with the fan.
Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

#### sonnyyu

#4
##### Jun 21, 2013, 03:48 amLast Edit: Jun 21, 2013, 06:26 am by sonnyyu Reason: 1
Murata  microblower is its piezoelectric ceramic based drive system that allows for an extremely compact and thin unit.

• Power: 0.18W

• Drive Voltage: 15 Vpp - 19 Vpp

Microcontroller drives piezoelectric buzzer at high voltage through one pin

http://www.edn.com/design/systems-design/4394277/Microcontroller-drives-piezoelectric-buzzer-at-high-voltage-through-one-pin

Change voltage to 7.5 ~ 9.5 v.

#### rookie6

#5
##### Jun 20, 2019, 10:40 pm
The device is resonant at 24-27kHz according to the datasheet, so a square wave drive through a small inductor should be OK. In fact page 17 shows a square wave drive.

Unfortunately, the datasheet does not appear to give any indication of the power consumption of the device, other than that the output transistors in the suggested circuit are specified as 500mA types. The NE555 is rated at 225mA, so it might be sufficient at lower drive voltages. My choice would be to generate a 26kHz square wave using one of the Arduino counter/timers, and use a MCP1407 mosfet driver chip to amplify the output and drive the device at up to 18Vp-p. Connect a small inductor and a 1uF capacitor in series between the MCP1407 output and the fan, and a resistor (e.g. 100k) in parallel with the fan.
Hi David
You had the same great idea as MarkT with use of the mosfet driver chip. But markT recommended MIC4422. I was wondering based on what attributes should I choose the driver chip? I learned that piezoelectirc speakers parts are capacitive loads with values between 10nF and 1μF. Is ''Capacitive Load Drive'' of the drive chip decisive?
I would love to use the whole voltage range of the device up to 20Vpp (not only till 18Vpp) Is there chance there is on driver chip available which fits?
I attached a diagram showing the implementation of the MCP1407 Is it correct? What's ''small'' inductor
David , thanks for a Feedback.
Michal

#### hammy

#6
##### Jun 20, 2019, 10:52 pm
I got this from google .. weird

http://forum.freetronics.com/viewtopic.php?t=5352

#### rookie6

#7
##### Jun 23, 2019, 07:02 pmLast Edit: Jun 23, 2019, 07:03 pm by rookie6
I got this from google .. weird

http://forum.freetronics.com/viewtopic.php?t=5352
from what I have learned 26kHz ist too fast for regular MOSFET but ok for a IC MOSFET Driever. Do not kow how it worked out in http://forum.freetronics.com/viewtopic.php?t=5352 . No conclusion was posted.

I think a Motor load and an Piezoelectric load are a bit diferent things, not sure however. I like the idea of the driver chip and already two people on this forum proposing this solution.

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