Powersupply with long wire gives problems

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Hi,

I have a 5 volt powersupply (2,5 A) and I have connected a long wire (+/- 4 meters) to the 5V side.
Then I reduce the 5V to 3.3V with a Lm1117 and connected the esp8266 to it with the 3.3V.

Without the 4 meters wire between the powersupply and the LM1777 everything works fine.
But as soon I extend the distance to the powersupply with the 4 meter (speaker)wire the ESP8266 doen’s work anymore or not reliable (sometimes I can ping it).

I also tried to add capacitors to the esp8266 between ground en 3.3v. I tried 1uf, 10uf en a 100uf electrolyt all the same time.
It improved a litte bit but still a lot of trouble.

I don’t understand why the 4 meter of wire is a problem and how i can solve it.

Thanks in advance

not sure, but did you try a thin or thick cable?
maybe the resistance of the cable is too high?

@lschip Did you pull the reset line to 3.3V using a resistor, e.g. 10k?

@lschip said in Powersupply with long wire gives problems:

I don’t understand why the 4 meter of wire is a problem and how i can solve it.

Take a multimeter and measure the voltage at the end of the 4m wire. As leader21 sugested maybe the resistance of the cable is too high and you have a too low voltage at the end.

Thanks for your reactions.

The wire is 2,5 mm, is speakercable. That should be thik enough.
The voltages are right, more the 5 volt on the lm1777 and from there 3,3v on the ESP.

I did not use a 10k resistor to the resetline, should I? Does that helps?
I can try that…

@lschip said in Powersupply with long wire gives problems:

LM1777

Can you measure the voltage arriving at the voltage converter?
As it has a voltage drop of about 1V it should be at least 4.3V for 3.3V output.

its just some more than 5 volt…

@lschip said in Powersupply with long wire gives problems:

I did not use a 10k resistor to the resetline, should I? Does that helps?

Yes, give it a try. It most likely will solve your problem.

Ok, also the 10k resistor from RST to 3.3V does not help.

With a short wire I get 0% packetsloss with ping.
With a long wire I get 92% packetloss with ping.

So I think its resetting somehow.

@lschip said

The wire is 2,5 mm, is speakercable. That should be thik enough.

2.5mm² is too thick if you ask me.
use a telephone wire or a cat5 network cable and try again.
usually you are using very thin cables for jump wires, since there is not much power to transfer. had a 5 meter wire from the pi to a hall sensor on the gas meter with a telephone cable attached. no problems at all.

In general thick cable should only improve things. Thicker cable equals less resistance. Sure there are very cheap speaker cables out there which might have a higher resistance than a telephone cable.

As he measured >5V at the end of the cable the resistance should not be the reason.

• Where is the long cable running? Are there any other cables or wireless transmitters near by which could cause interference?
• Is the ESP in the same position when testing with the long cable or is it at its destination position (which might have very different wifi coverage)?

As the esp is quite picky about power quality a shielded cable twisted pair cable might help as well as the capacitors you have already tried.

If the position is different try to move the ESP a bit away from potential sources of interference or think about using a module with an external antenna.

I also thought that a thicker cable could not be bad.
The position of the esp with a short cable is the same as with an long cable.

I also will try some other wire to be sure…