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Welcome to the espros wiki! a ROS serial for ESP8266 through WiFi

2017 Agustin Nunez ([https://github.com/agnunez/espros.git])

This is an adaptation of ROS-serial-arduino to run on an stand-alone ESP8266 with WiFi instead of wired USB UART cable, based on [http://answers.ros.org/users/1034/ahendrix/] proposed solution for Arduino with WiFi shield.

The reason being that ESP8266 (or ESP32) are much powerful and cheaper tha AVR Arduinos with more memory and speed and integrating WiFi for 10 times less cost. The use of I2C or SPI in ESP8266 allows to expand the number of GPIO's at wish. The vision is that every sensor or actuator node in a ROS-robot can be created using a single $2 ESP8266, with just power supply or powerbank battery, avoiding harness and reducing total cost.

esproswifi

Example program taken from [http://answers.ros.org/users/1034/ahendrix/] for Arduino and adapted to ESP8266, NodeMCU dev module. Please, modify ssid/password of your Wifi and IP of your roscore server. Your ESP8266 will try to connect to 11411 port at that server IP To allow the connection, run roscore of course, and later:

    $ rosrun rosserial_python serial_node.py tcp

chatter

The standard ros tutorial client, working via Serial cable adapted for ESP8266 This example is particulary suitable for Witty ESP8266 dev platform and allow to toggle all its leds by publishing to /led topic with stdmsg/Int16 that correspond to its gpio pin ESP12E number, (i.e. 2,12,13,15)

CarEspRos

NodeMCU with motor shield and 2 DC motors plus infrared encoders wheels (DoIt car) implementation in ROS WiFi with esproswifi approach. Encoder counters are pusblished and basic movement with time length as subscriptions. Car is moved with messages like:

$ rostopic pub -1 /car/forward std_msgs/Int16 1000 // to move foward 1000 ms, use backward, right or left

Car encoders can be read with:

$ rostopic echo /car/leftencoder

CarEspRosServo

This is a version of CarEspRos above with addition of Servo in D7 nodeMCU pin (GPIO13 of ESP12). This Servo ROS subscription can be used, to rotate a Steering Wheel, or other usages. See later. Message to publish is:

$ rostopic pub -1 /car/angle std_msgs/Int16 80 // to adjust to Servo center angle (min:0, max:255)

This code is part of a much larger project to build an open source ROS Robot, called Gara

Have fun,

Agustin