- Sun May 03, 2015 6:32 pm
#16407
ramsbod wrote:I am using a voltage divider on the TX and RX using 10MOhm and 20 MOhm resistors. I am not sure this is needed from the TX pin on the ESP to the RX pin on the Arduino.
First; 10 MOhm is way too much. 10 kOhm might work, especially for slow speeds. 1 kOhm is robust, but may waste a little bit of electricity. (And then 20 kOhm / 2 kOhm for the pin-to-ground part.)
For the ESP->Arduino side, you should not use a resistor between pin and ground, because this will just make the 3.3V out of the ESP even lower, and the Arduino is unlikely to see that signal at all.
In general, though, I'd recomend using a level shifter circuit. You can easily make one from an N-channel MOSFET, or you can buy one for a couple of bucks from Sparkfun or Adafruit (or on eBay.)