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What level shifter do you use?

PostPosted: Fri Jan 16, 2015 5:25 am
by gmc
I'm having endless problems getting the ESP to talk to the Arduino and have built a range of level shifters.

I've tried building this one:

Image

The 5V to 3.3V works fine and I can transmit data from the Uno to the ESP.

I've tried building the 3V to 5V in the diagram and its not working. If I connect the ESP TX to directly to the Uno's RX it works fine - but put it through any kind of level shifter and it stops working.

Also tried building this one - no go.
Image

What level shifters do you guys use that give no issues?

Re: What level shifter do you use?

PostPosted: Fri Jan 16, 2015 7:00 am
by elac
I use a CD4050BE chip, $0.24.

Re: What level shifter do you use?

PostPosted: Fri Jan 16, 2015 7:11 am
by gmc
Thanks - might just try one of these. Tired of messing around.

Re: What level shifter do you use?

PostPosted: Fri Jan 16, 2015 11:05 am
by McOffsky
You need level sniffer / voltage divider only on Arduino->ESP8266 connections (Arduino TX -> ESP RX or Arduino Digital Pin -> ESP RST, etc). You don't need 3.3 to 5v "sniffer" between ESP TX and Arduino RX. I'm using divider builded on 220om and 390om resistors.