How to read a 0–60V single-wire pulse signal with Arduino/ESP32?

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1

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Title:
How to safely read a 0–60V single-wire pulse signal with a microcontroller?

Body:
Hi everyone,

I am working on a project where I need to read a single-wire digital signal that swings between 0 V and 60 V. The signal comes from an air conditioner inverter board (Daikin), and it looks like a pulse/data line rather than an analog waveform.

My goal is to feed this signal into a microcontroller (Arduino/ESP32, 3.3V or 5V logic) in order to detect the pulses (count them or possibly decode data).

I’m trying to figure out the best way to safely interface this 0–60 V signal to my MCU:

  • One idea is to use a resistor divider + comparator (e.g., LM393) to bring the voltage down to logic level.
  • Another option could be an opto-isolator for galvanic isolation, but I am not sure which type is fast enough. I know PC817 is common, but I’ve read it’s quite slow.
  • Are there any ready-made modules that can do this level shifting or isolation for such signals?

My questions:

  1. What is the recommended way to convert this 0–60 V pulse signal to 3.3 V or 5 V logic safely?
  2. If isolation is preferred, which optocoupler (or digital isolator) would you recommend?
  3. Would a simple divider + comparator be sufficient if isolation is not required?

Thanks in advance for your advice!

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4

@tuan3289 ,

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Thank you

5

Use an opto-coupler simply.

6

@tuan3289
Where are you measuring a 60V signal?
VXL on Q1 collector is only 5V

7

And what are you using to measure this signal with? And is it measured against the device ground or does the signal have a matching wire that you are missing?

8

I have doubts Daikin uses 0-60V digital signals.
How you got this ?

9

I am making a device called daikin air conditioner checker it can read the signal between indoor and outdoor and also many parameters I am wanting to develop it

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10

I don't see 60V on your schematic.
Where is 60V?

11

What do you mean by a single wire pulse?

The first thing you want to do is take care, even if it is 60-V. It could make you tingle a bit.
I think this is potentially dangerous work and you need to be absolutely sure on where you take the measurement, especially the ground it's referenced to.

If you have access to an oscilloscope, that would be the safest way to approach it and get a proper view of what's going on.

If it's a pulse, you need amplitude, pulse width, frequency.

If you aren't sure, don't do it.

12

I am making a device called daikin air conditioner checker it can read the signal between indoor and outdoor and also many parameters I am wanting to develop it

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image333×180 30.7 KB

13

So at what point are you in your development? What is the circuit you posted? How you got that 0-60V?

14

@tuan3289
I don't see 60V on your schematic.
Where are you measuring this 60V pulse?