ESP8266 Community Forum

- Tue May 17, 2016 2:10 am #47551 I’ve been using a few esp’s to get measurements from sensors like the DS18B20 and SI721. I let the ESP run a webserver and pull the data from it.

To hook the ESP up, I’ve mainly used this schema:



Except for the capacitor, I used a 470uF one.

Next to the schema above, I add a few more things, depending on what kind of sensors I’m working with:

Single wire sensors (Like DS18b12): pullup resistor of 4.7k on data pin
i2c sensor (like SI7021): pullup resistors of 10k on SCL and SDA

Most of the times it works great, but every now and then, the esp’s seem to freeze, and only a reboot brings them back to live. Sometimes this happens after a few weeks, sometimes after a few days.

Googling for esp-12 wiring brings many different variaties of possibilities up. I’ve seen setups with multiple capacitors, different resistor values, etc.

I am planning to convert my prototype boards into a real PCB design, but for that I first want to make the hardware configuration as stable as possible. can you give me any advice on what I could change to make it more reliable?

- Tue May 17, 2016 4:23 am #47555 Try to add a resistors 10k to GPIO2 and RXD too. This connection I am using for ESP8266-01, which is practically the same as ESP8266-12 wiring. The value of pullup resistors or capacitors is not critical. The most important thing is to have a good power source. What software do you use? I run Lua server without any problems now.

http://esp8266.fancon.cz/barometer/esp8266-wifi-barometer-bmp085-bmp180.html

- Tue May 17, 2016 4:55 am #47556 I usually use GPIO2 for the DS18B12 sensor, so I already have a pullup of 4.7k on it. I will try to add a pullup on RX (I now just have it floating).

For power I use a LM1117 that I feed with a 5v adapter.

- Thu Apr 27, 2017 11:16 am #65340 I have bought in the past months from different dealers ESP12E. Total of 8 pieces. Two are very stable and work without a reboot and without reset a simple counter program. The two have also no pullup or capacitors connected, power source PC USB. Still great.

The four others are constantly falling. Usually after a few seconds or minutes. With capacitors and pullup, the stability can be increased but they nevertheless fall off after a simple counter program after 8 to 40min. The current source does not matter, even at 3.4V 2A and several 3300μF and 100nF capacitors.

The four I then thrown into the garbage. Yesterday I received a new 12E. He also has problems. I have removed the metal screen. Have the main processor exposed to high temperatures, no change. When I am with the soldering iron, I have unintentionally removed a SMD item. Suddenly, this 12E ran smoothly without crashing! But unfortunately also without WLAN.

I believe that many are flawed. Waste of time to try to stabilize them. Better looking the stable ...