ESP8266 Community Forum

- Mon Feb 16, 2015 8:09 am #9915 For one thing you don't need separate power supplies. The power supplying the Arduino is available at the Vin pin, so connect that to your ESP8266's voltage regulator.

Where are the input and output caps for your voltage regulator? And add a decoupling cap on the power pins to the 433MHz module, as close as you can; I would solder a 0.1uF right on the header pins.

- Tue Feb 17, 2015 1:22 pm #10028 Ok, I removed the second power supply and added capacitors. (470 µF before the voltage regulator, 10 µF behind the voltage regulator, 0.1 µF on the ESP-01 headers and 0.1 µF on the 433MHz receiver's header.)

Now the Arduino's 5V line isn't dropping any longer. Sadly it seems, that the dropping 5V line wasn't the only problem. The "data line" of the 433MHz receiver still puts out a creepy signal, when the ESP-board is powered. Have a look at the following screenshot, which shows the signal of the 433MHz receiver when the ESP is powered and when it isn't.

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- Tue Feb 17, 2015 2:47 pm #10042 Is this only a problem when the ESP is transmitting? Can you put the ESP in a grounded metal box to see what the effect is? Or getting the ESP to transmit often and observe your scope?

Another possibility is that because the ESP-01 is not properly shielded noise is being coupled into the 433MHz module through the antenna. Can you try a different antenna configuration? Or try putting a grounded metal plate between the two RF devices?

EDIT: "grounded" metal box.

Last edited by MK1888 on Tue Feb 17, 2015 3:18 pm, edited 1 time in total.

- Tue Feb 17, 2015 3:05 pm #10046 This happens from the moment when the ESP is powered. No difference if ESP is transmitting or just idling.

Furthermore I think that it's no problem with WiFi/radio because if I power the 433MHz receiver by an external powersource and not by the Arduino, everything is fine. Only if the ESP and the 433MHz receiver are powered by the same supply (or atleast have linked grounds) the problem occurs.

If I power the Arduino and the ESP by different power supplys also everything is fine (except for the serial connection between Arduino and ESP because of the missing ground link.) So there must be a problem with the circuit.

Last edited by rherrmann on Tue Feb 17, 2015 3:17 pm, edited 1 time in total.