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Topic: Can I make an Arduino nano work like a relais (Read 409 times) previous topic - next topic

alex5678

I am thinking of using the Arduino nano, that reading a signal from his analog input, and sometimes send this input as it is to the output, and sometimes to cut it....

So why I don't use a relais you may think. The problem is that I have made all the connections to the project in the box, and there is no space, I will have to rebuild it, something I want to avoid...

So can I use the Arduino nano's pins as relais?

Thank you....

Delta_G

No, it won't work like that.  You will have to either use a relay or a transistor. 
|| | ||| | || | ||  ~Woodstock

Please do not PM with technical questions or comments.  Keep Arduino stuff out on the boards where it belongs.

alex5678

Ok relais, I understand it, but transistor? How can this work?

Paul__B


alex5678

Research 74HC4066.

Can it support up to 5 kHz signal? I mean, I won't  have any problems with distortion, slew rate etc, right?

dave-in-nj

The output pin of any of the Arduino boards is minimal you should not pull more than a few milliamps how much power are you looking for on the output?

Delta_G

Can it support up to 5 kHz signal? I mean, I won't  have any problems with distortion, slew rate etc, right?
This is the first you mention these requirements.  Please do not waste other people's time.  If there are more details and requirements please get that out now before anyone else wastes time talking to you without complete information. 
|| | ||| | || | ||  ~Woodstock

Please do not PM with technical questions or comments.  Keep Arduino stuff out on the boards where it belongs.

wvmarle

So what are you trying to do, really?

Just relay a signal?

Switch the power to some other device?

5 kHz as such is no problem but there are different approaches, depending on the actual requirement. An electromechanical relay is anyway out if you're looking at a 5 kHz on/off signal, they're far too slow for that.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

sterretje

Can it support up to 5 kHz signal? I mean, I won't  have any problems with distortion, slew rate etc, right?
I think everything you asked for and need to know is in the datasheet that was provided in reply #3.
If you understand an example, use it.
If you don't understand an example, don't use it.

Electronics engineer by trade, software engineer by profession. Trying to get back into electronics after 15 years absence.

wvmarle

I am thinking of using the Arduino nano, that reading a signal from his analog input, and sometimes send this input as it is to the output, and sometimes to cut it....
Coming back on this again, trying to understand what's going on.

You have an analog signal, when it's above a certain value switch on the output, when it's below a certain value switch off the output, right?

If so it sounds what you need is a comparator (either dedicated or OpAmp wired as such) for triggering on/off around a rather specific voltage, or a Schmitt trigger, which has hysteresis built in so you get a bit less spurious switches. You may need an amplifier and/or voltage divider to get to switch at the desired level.

Then the output signal can in turn be used to switch a transistor or MOSFET to switch power to whatever load you want to switch, if needed.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

alex5678

#10
Oct 11, 2018, 09:55 am Last Edit: Oct 11, 2018, 09:55 am by alex5678
Sorry for the delay...

I have an input with signal 1, I want this signal 1 to go to output as it is, but sometimes I want the signal 2 go to output (produced by Arduino) and when signal 2 exists on the output, signal 1 does not exist on the output. And when signal 1 exists on the output, signal 2 does not exist on the output.

Please see attachment...

Thank you

wvmarle

So what is the exact nature of this input signal? You only mentioned analogue and 5 kHz.
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

alex5678

#12
Oct 11, 2018, 10:09 am Last Edit: Oct 11, 2018, 11:38 am by alex5678
So what is the exact nature of this input signal? You only mentioned analogue and 5 kHz.
Signal 1 is from telephone line...300Hz - 5000Hz,
Signal 2 is a signal produced by the Arduino...

Also, I want to ask this: If I set a pin of Arduino nano as OUTPUT, and I send 5 Volts to this pin from another circuit, could I cause any damage to the Arduino/pin?

Thank you...

wvmarle

Signal 1 is from telephone line...300Hz - 5000Hz,
That is a voice signal or the ring signal?

How do you plan to turn this in a 0-5V signal the Arduino can read? Phone lines produce pretty high voltages, 50-80V or so.

In what way does this have to be relayed? Exactly as is, or does the presence of a signal on that input have to produce a digital output signal?

What is this "signal2" supposed to be?

What is on the listening end of this "Signal1/Signal2" output?

Quote
Also, I want to ask this: If I set a pin of Arduino nano as OUTPUT, and I send 5 Volts to this pin from another circuit, could I cause any damage to the Arduino/pin?
Yes - that 5V is not the same as the Arduino's HIGH 5V output so the two voltages will fight each other. If the Arduino's output is set to LOW it's even worse. At the very least you should add a current limiting resistor (at least 250Ω to limit the current to a safe 20 mA, but depending on what you're really trying to do you may want to increase that value to 10k or more).

I'm assuming that these two circuits share grounds.

OK, enough of this dragging information out bit by bit. Why don't you just give the COMPLETE picture now?
Quality of answers is related to the quality of questions. Good questions will get good answers. Useless answers are a sign of a poor question.

dave-in-nj

Signal 1 is from telephone line...300Hz - 5000Hz,
Signal 2 is a signal produced by the Arduino...

Also, I want to ask this: If I set a pin of Arduino nano as OUTPUT, and I send 5 Volts to this pin from another circuit, could I cause any damage to the Arduino/pin?

Thank you...
the correct answer is that we cannot know. you have withheld information on power.
what is that 5v signal ?   if it is a 1mA signal from some sensor or other device, then the Arduino will damge THAT device.
if it is a 200mA signal then it will damage the Arduino.
again, what power levels are to taking about.    So far nothing makes any sense because the complete information has not been presented.
if you want to isolate the two circuts, that is easy to do.
if you have low power signals, you need to know what will happen on each end when it is brought high or low while it is low or high.
the specs of the arduino are plain and simple.   each pin has a power limit for supplying power or receiving power. 



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