Generating multiple sine or square waves

Projects General Guidance
1

I need to generate waves to run piezo transducers at 60kHz frequency and 10-20 volts (it doesnt matter if they are square or sine waves). The trick is that i need to generate multiple (most probably 6) of these, all with different frequences which frequencies i can change with the arduino.
Because of this there is no way i can use the arduino PWM. I would also need this to be as precise as possible.

I thought of doing it with astable (op-amp) multivibrators where i would use some kind if variable resistance that i can controll with the arduino and thus controll the frequency, but since im inexperienced with this im not sure if its the best way or if it would be a good idea at all.

Could anyone point me on the right direction on this?

Fyi im using an arduino uno if thats relevant information at all

2

You either need a timer per piezo for a hardware solution or you need a sufficiently fast Arduino for a software solution.

3

Use an AD9833 and an amplifier for each channel. A bit overkill but you get very good control. There are multiple breakout modules for the chip available. They claim up to 12.5 MHz for sine waves, but above 3-4 MHz the output gets rather grainy and the output decreases.

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4

generating 50KHz pulses with an ESP32 using a timer interrupt is simple - see creating-a-modulated-signal-using-timers-with-a-variable-duty-cycle, e.g. 100KHz
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however, six with different frequencies would probably require multiple ESP32 devices
how are the frequencies related to each other? are they synchronised in some way?

5

No, the frequencies would change independently.

6

Thanks, i will look into it. I really couldnt image myself needing anything higher then 100kHz, and i only need to be able to wary the frequency a few percentages. I was also looking into an IC called "ICL8038", where i could change its frequency with some digitally variable resistor, is that viable?

Edit: nevermind, youre suggestion seems to be much better suited for my uses. Quick question though since i havent really built anything like this before and since we are already here what kind of amplifier would you use?

7

The ICL8038 is a very old analog chip, it has long been replaced by easier to use DDS chips.

I haven't designed an amplifier in ages, so don't have much advice.
Some things to consider.

  • The piezo transducer is a capacitive device so normal audio designs might have problems
  • If the transducer doesn't need to be grounded you can use a bridge circuit to double the voltage across it.
  • I would check on high voltage op amps and stereo audio amps to see if any of them are possibilities.
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