ESP8266: Using a seeeduino to talk to the ESP8266 module directly

Daniel Eichhorn — Sat, 06 Dec 2014 13:00:00 +0000

I recently received two of these shiny new Wifi modules from China and had to test them out. In many posts around the web they say you should use a serial-to-usb adapter to send some AT commands to the module and set it up with your local access point. My problem was: I didn’t have such an adapter, or so I thought. It turns out you can use some types of Arduino’s for the job just fine. I had a Seeeduino V3.0 laying around and that piece of hardware really has a few features built in that I wasn’t aware of before. This is a short explanation on how to setup the Seeeduino to talk to the ESP8266:

Upload the following sketch to your Seeeduino:

void setup()
{
pinMode(0,INPUT);
pinMode(1,INPUT);
}
void loop()
{
}

Open the serial console of the Arduino IDE and set the baudrate to 115200
Now wire the ESP to your arduino:

ESP8266 Seeeduino

GND GND

VCC+CH_PD V3.3

URXD RX (pin 1)

UTXD TX (pin 2)

ESP8266	Seeeduino
GND	GND
VCC+CH_PD	V3.3
URXD	RX (pin 1)
UTXD	TX (pin 2)

Now send some AT commands for testing (bold is the request, light comments and response):

AT
OK
AT+RST         // resets the module
 ets Jan  8 2013,rst cause:4, boot mode:(3,6)

wdt reset
[..]
csum 0xbd
AT+CWLAP       // lists all access points     
+CWLAP:(0,"",0)
+CWLAP:(3,"ap1",-90)
+CWLAP:(0,"ap2",-87)
AT+CWJAP="ap1","mypwd"     // join access point ap1 with password mypwd
OK
AT+CWJAP?     // show connected access point
+CWJAP:"ap1"

Turn on/off USB Power on TL-MR3020 running OpenWrt to restart Arduino

Daniel Eichhorn — Wed, 18 Sep 2013 06:28:00 +0000

In a later blog post I will describe how I am using a TL-MR3020 router as low-cost wifi shield for my Arduino to transmit sensor data over wifi. In this post I just want to show how you can script a restart of the arduino by powering off the USB port that the Arduino is connected to. In need this because sometimes the arduino does not send anymore data to the ttyUSB0 device. So as a workaround I’m restarting the Arduino from time to time by cron job.

#!/bin/sh
echo 0 > /sys/class/gpio/gpio8/value
echo 1 > /sys/class/gpio/gpio8/value
echo "$(date)" >> /tmp/restart.log

low cost wifi shield – Squix – TechBlog

ESP8266: Using a seeeduino to talk to the ESP8266 module directly

Turn on/off USB Power on TL-MR3020 running OpenWrt to restart Arduino