ESP8266 Community Forum

- Sat Jul 04, 2015 7:02 pm #22458 Switching to STA+AP and back makes my module unreliable until I reboot. I get those -3 errors I described. Pages often won't load, etc. I haven't updated the SDK yet, though.

- Sun Jul 05, 2015 3:44 pm #22516 My bug report:

Problem: Smartphone or any other client device can not connect to esp8266 in AP+STA mode.
As soon as the module is lightly touched near the antenna it works.
Once connected the finger can be removed and the connection is still stable.

Note: The signal strength is quite weak when trying to connect, as soon as the
finger is "used" it greatly improves and stays strong once connected even after finger removal.

Wiring:
GPIO0 -- 5kOhm -- VCC (ams1117)
CH_PD -- 5kOhm -- VCC (ams1117)
VCC -- VCC (ams1117)
GND -- GND (ams1117)
GND -- GND (cp2102)
TX -- RX (cp2102)
RX -- TX (cp2102)
Between VCC and GND is a 220uF 35v Capacitor

Reset is not connected as it is pulled high by an internal resistor, also the device does not reset at any time, so this seems no problem.

This hardware setup works for other esp-01 modules I have without a problem.

Exact version:
commit fc784cc6b5e98979016509a462d0bc6674b42a4f
Date: Sat Jul 4 13:41:57 2015 -0700

Steps:

Code: Select allgit clone https://github.com/pfalcon/esp-open-sdk
cd esp-open-sdk
make STANDALONE=y
wget http://bbs.espressif.com/download/file.php?id=564
mv file.php\?id\=564 esp_iot_sdk_v1.2.zip
unzip esp_iot_sdk_v1.2.zip
cd ..
git clone https://github.com/jeelabs/esp-link
cd esp-link
git submodule init
git submodule update

Now edit Makefile to set sdk path and serial interface

Code: Select allexport PATH=/home/user/esp8266/esp-open-sdk/xtensa-lx106-elf/bin:$PATH
dd if=/dev/zero bs=1k count=512 | tr '\000' '\377' > blank512k.bin
../esp-open-sdk/esptool/esptool.py --port /dev/ttyUSB1 --baud 460800 write_flash 0x00000 blank512k.bin
make flash

Now the real dilemma, I have another esp-01 module that works with the exact same steps and hardware setup. I even did this:

Connect "good" esp-01 module

Code: Select all../esp-open-sdk/esptool/esptool.py --port /dev/ttyUSB1 --baud 460800 read_flash 0x00000 524288 esp8266_working.bin


Now connect the "bad" esp-01 module

Code: Select all../esp-open-sdk/esptool/esptool.py --port /dev/ttyUSB1 --baud 460800 write_flash 0x00000 esp8266_working.bin


But it still did not work!

At this point everybody will say the module is just damaged, right?

This is the evil twist:

Code: Select allgit clone https://github.com/israellot/esp-ginx
cd esp-ginx

Now edit Makefile to set sdk path and serial interface

Code: Select allmake flash

And it works - no problem at all!

HELP!

Last edited by iothing on Sun Jul 05, 2015 5:25 pm, edited 1 time in total.

- Sun Jul 05, 2015 5:24 pm #22526 My gf just recommended placing a piece of wire on the antenna, so here you go:

That "magic wire" actually works as good as the finger

- Mon Jul 06, 2015 1:12 pm #22607 Congrats, you invented the Yagi antenna. Either that or by de-tuning it you decreased the intensity of the current spikes to the transmitter and the module runs more stable off a badly buffered supply?

Try soldering the capacitor directly onto the pins of the module. Also keep in mind that it is not only the antenna that makes wireless communication possible. You also need a proper ground plane as "counterbalance" for the dipole.