ESP8266 connection to Uno R3

The ESP-01 is officially a 3.3v device, but I've heard of people just hooking them up straight to the 5v pins (maybe powered by the 3.3v Uno pin, not sure). To be safe you'll probably need a level-shifter though.

But you don't actually need a Uno for it.

I'm currently using one as a data logger, standalone, in a little tictac case:

The biggest limitation is that it only has one easy to use GPIO pin. Two with a little more effort, and I think 4 with a fair bit more effort.

I'm just using it with a Dallas 1-wire temperature sensor, and it calls a simple php script on my server that updates a basic text file. With a bit of magic, I'm getting real-time graphs of the temperature I'm tracking. I just put that together last night - went quicker and turned out nicer than I had intended!

ps, the dip in temperature is when the heater and datalogger got unplugged for 25 minutes. Oops! but it was easy for me to detect and fix (ie, plug it in again), due to this data logging!

You can also get other ESP8266 boards that have far more GPIO, like the WeMos D1-mini or the Witty. Each is about $5 on eBay. Or for about $7 (CAD) you can get a Sonoff which can also be programmed like an ESP8266 but it already has a power supply, case, and relay. Adafruit has the Huzzah for more, but it seems to do about the same thing - maybe better quality and better support though. (I have one of each of the aforementioned items on order, to try them all out )

edit: I forgot to mention that they are all programmable with the Arduino IDE. The ESP-01 is more difficult because you'll need a USB-serial adapter and a few extra hookups. That all said, it will probably make a very nice WiFi add-on to a Uno as well, and much easier to program that way.

Cheers,

-Nico

Note: The ESP8266 Module is not capable of 5-3V logic shifting and will require an external Logic Level Converter. Please do not power it directly from your 5V dev board.Note: The ESP8266 Module is not capable of 5-3V logic shifting and will require an Wesley,

From the Sparkfun page for the ESP8266 module:

Note: The ESP8266 Module is not capable of 5-3V logic shifting and will require an external Logic Level Converter. Please do not power it directly from your 5V dev board.

So be careful.

Gene

Wesley,

Wow, that got a little messed up.

Just another thought.  You could modify you Uno to operate at 3.3V by replacing the 5.0 regulator on the Uno board with a 3.3V one.

Gene

Just found a I2C Logic Level Converter Bi-Directional Module 5V to 3.3V in my bin whats the odds.  Should do the trick.

Take care of the 3.3 supply also, the ESP can draw up to 320mA at startup.

>You could modify you Uno to operate at 3.3V by replacing the 5.0 regulator on the Uno board with a 3.3V one.

Could you supply regulated 3.3v to the 5v pin directly?

So should I be running the rx and tx through the board or just the 5v - 3.3v?  or am I way off on that?

Arduino TX -> ESP RX and Arduino -> ESP RESET through the level shifter

ESP TX -> Arduino RX is fine, 3.3v is good enough for a 'high' signal

I would power the ESP board from the 3.3v pin of the Uno (to ESP vcc), and run rx/tx through that little level shifter board. If I recall correctly, the level shifter board will have 5v power input on the Uno side, and a 3.3v power input on the ESP side. So I'd connect those up to the Uno 5v and 3.3v pins respectively.

Looks like this project on Hackster shows all the details: https://www.hackster.io/circuito-io-team/simple-arduino-uno-esp-8266-integration-dba10b

Cheers,

-Nico

oh right, I keep forgetting about the reset!