ESP8266 Community Forum

- Thu Jun 25, 2015 7:34 am #21606 Hello,
I bought an ESP8266-01 and tried to connect it to an arduino uno. My arduino uno had BareMinimum in it.
I used an LM2596 board as an external power supply, and a bidirectional logic level converter. Here are my connections:
TX(ESP) --- LV1 *** HV1 --- RX(Arduino)
RX(ESP) --- LV2 *** HV2 --- TX(Arduino)
OUT+(LM2596/3.3v) --- Vcc --- CH-PD --- LV *** HV --- 5v(Arduino)
OUT- (LM2596/3.3v) --- Gnd(ESP) --- Gnd *** Gnd --- Gnd(Arduino)
IN+ (LM2596/3.3v) --- Vin(Arduino)
IN- (LM2596/3.3v) --- Gnd(Arduino)
RESET(ESP) --- RESET(Arduino)

When I tried to power the arduino with 5v from my desktop, ESP8266 didn't respond, and the power led wasn't on. When I tried to power the arduino with 9v-1.5a power supply, the power led was on, but ESP8266 was so hot that I couldn't touch. Also there was smoke. I tried AT in the serial terminal but there was no response. I couldn't even see my commands in the terminal window when I send them. I tried both 9600 and 115200, with CR-NW. Then, in the second try with 5V, the same thing happened. ESP8266 was very hot, and there wasn't any response. When I researched about the topic, I saw that the power led with resistor is problematic. I tried removing the led, but I couldn't solve the problem. Do you have a suggestion? Did I burn my ESP8266?
Thanks for your help!

- Thu Jun 25, 2015 11:40 am #21633 The ESP8266 is a 3.3V chip. Your problem may simply be that you are trying to power it with 5V which would be a no-no. Can you provide a schematic of what you built?

See also this thread:

viewtopic.php?f=13&t=3721

I am a "weekend ESP8266 novice" and this weekend I managed to get my 3 ESP8266s to boiling point with no explanation (that I can find).

Neil

Free ESP8266 book available for download here.

- Fri Jun 26, 2015 11:01 am #21772 My schematic is attached to this post. I'm sure I powered it with 3.3 because I measured Vcc-GND with a multimeter. I wonder if I can ever make it work.

Attachments

- Fri Jun 26, 2015 1:39 pm #21797

My schematic is attached to this post. I'm sure I powered it with 3.3 because I measured Vcc-GND with a multimeter. I wonder if I can ever make it work.

If your diagram is correct you have the Vin from the arduino board connected to both Vin and GND of the regulator. (black wire on far right)

i assume that is just a drawing error and it is supposed to be the line above for ground.

I can tell you that LM2596 need a good 1A+ pulse to get themself kick started. If you limit that current they will go into a linear mode and you get input voltage on the output rail. been caught by it before .. 24v on a 5v rail ..
It may well have been 3.3v when fired up without a load, but add the esp in and it may not have started nicely.


You should feed the LM2596 directly from the supply and not through the skinny little arduino tracks, breadboard links and wires.
Your esp is deceased as I guess you have figured.

LM2596 is a bit of a dirty supply as well at low currents, it has to run a discontinuous mode turning on and off, makes it very noisy, you are better off having it supply 5V and having a 1A linear low dropout reg feeding 3.3v to the esp. better yet .. remove it from your setup entirely if you are using small supplys.
They work fine when kicked in the guts with say 12v from a car battery or a large power supply but trickle feed them startup current and you are going to have a bad time .. eventually.

This is not mentioned in the TI docs, they say something like 'may not work properly' ...
I had a play with one on a current limited supply, sure enough, limit the current to under 800mA or so (it depends on input and output voltages and load) and it fails to start and you get full rail on the output.