ESP8266 Community Forum

- Tue Dec 09, 2014 2:54 pm #4414

I did, and it did!



Vin == Arduino TX
Vout == ESP RX
R1 == 1K
R2 == 2K

I'm inclined to try 10 and 20K...

That did not work for me.
Even the 100ohm and 200 ohm devider.

The esp8266 is driving me nuts, when I send commands, I see the blue led lighting up. I only have some BC547's, so I've build this level shifter,

but still the same. I receive data on my arduino, but can't send any command

anyone?

- Tue Dec 09, 2014 4:29 pm #4430 wild guess but it cost my hours. I had Ready to but AT didnt do anything:

if using Arduino IDE serial monitor, set line ending to Both NL & CR.

rgds

- Tue Dec 09, 2014 8:29 pm #4449 Are you at the correct baud rate? Can you see the "ready" message when you power the unit on?

Gary

- Tue Dec 09, 2014 10:52 pm #4450 Assuming normal USB to Serial communication (digital pin 0 = input (RX) and digital pin 1 = output (TX))...

In a perfect world you would use a couple of gates from a 4050 or two BSS138 to isolate TX/RX but you rarely have them lying around...

TX from the ESP8266 can be directly connected to the RX of the Arduino as the voltage never exceeds the 3.3 volts...
I used a 100R resistor because I'm paranoid even though the ESP8266 does appear to be 5 volt tolerant despite the datasheet...

RX from the ESP8266 can be isolated using a diode as in the attached image (voltage at ESP RX will vary from 3.3 to 0.7 volts)...

this-works.jpg

Strangely enough, the resistor divider did not work for me either

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