Saturday, February 22, 2014

Confessions of a FPV pilot. The rover - Part 5

Version 3.0 of the kitchen tray project has the tilt camera control.
Touching the black stripe on the right side on the dashboard is possible to change the camera tilt position with seven possible positions.

The mechanical construction seems perhaps too complex for a JFFP (just for fun project) like this. 
I did not build it now. I did it time ago to test a CNC that I builded.
Soon I will do a post about it.

A short video:

The servo is linked to the pin 11 of the Arduino Yùn.

All "Kitchen Tray Project 3.0" file are here.

Monday, February 17, 2014

Confessions of a FPV pilot. The rover - Part 4

This is the first video of the Rover 2-0.

To install and configure the web cam I used the instruction from this blog
It exactly what I was looking for and it's really clear and complete.
I bought the LifeCam HD-3000 and this is the result:.

All project files are here.
There are some improvements in the arduino Yun sketch and in the web server html page.
I also added some values to adjust the wheels' speed.
In the next post I'm going to add webcam pant/tilt.

Sunday, February 9, 2014

Confessions of a FPV pilot. The rover - Part 3

This is a short video of the very first version of the rover that I choose to call "Kitchen Tray Project "

You can download all project files here.

These are the instructions to hack the servos and below you can see the electrical links.

After the program upload into the Arduino yùn you have to open the REST API ACCESS from the configuration menù.

At this point you are able to open the rover web page with a tablet or a PC linked on the same net.
You have to write the Arduino yùn IP plus "/sd/rover" on the web browser address bar.
For example my address is:

And the WEB ROVER page will come up.

The WEB ROVER page has some buttons to controll the rover and a status field. Numeric values are used to set the number of Arduino cycles during which the command will be executed. This meaning that with a 50 ms of loop delay, each command will be executed for 2 seconds.
This is a security function to avoid problems. In this way the rover stop it if the ethernet connectios fails.
In the next version I'm going to add an automatic control connection protocol.

The HTML code is mainly formed by two side:
  • a table with the buttons icons and some numeric field.
  • 4 javascript functions. Two to send command and two to receive informations from the rover.

<input type="text" style="text-align: center" size="2" name="timeL" value="40" id="timeL" /><br>
<img src="left.jpg"  id="timeLimage" onclick="sendCommand(3,document.getElementById('timeL').value);"/>

When you press a buttont, the send Command function will be executed. This function has two parameters, the 3 and the 40 for text value

function sendCommand(mode,time)
          document.getElementById("info").innerHTML = "sent command >>>";
          server = "/arduino/mode/" + mode + "/" + time;
          richiesta = new XMLHttpRequest();
          richiesta.onreadystatechange = sendCommandResponse;
"GET", server, true);

The sendCommand function send a HttpRequest (it's like write an address on a web browser and press enter) with address: IP/arduino/mode/3/40. 
Thanks to web server and bridge library the Arduino sketch catch the string and from the string it get the numbers 3 and 40.

The code "richiesta.onreadystatechange = sendCommandResponse;" subscribes the answer from Arduino and tell that it will be managed by "sendCommandResponse" function.

 function sendCommandResponse()
          if ((richiesta.readyState == 4) && (richiesta.status == 200))
             esito = richiesta.responseText;
             document.getElementById("info").innerHTML = esito;
             response = esito.split("#");
             document.getElementById("info").innerHTML = response;
             mode = response[0];
           Ardumia67timeout = response [1];

That function "sendCommandResponse" refresh the string state field.

In the next post I'm going to add a webcam to the rover.

Tuesday, February 4, 2014

Confessions of a FPV pilot. The rover - Part 2

I'm going to explain the first version of the Arduino sketch to control the rover with a web browser.

Arduino sketch has the goal to receive some commands from the web server and drive the servos according to commands. To do that I use the Bridge library to read commands from web server and Servo Library to drive the servos.
The Arduino Yùn board has:
  • "Arduino" microcontroller 
  • micro PC on which "Linux run" and a web server . 
  • wifi board.

I wrote the following Arduino sketch starting from the Bridge and Servo library that you can read here and here.

//include the library

#include <Bridge.h>
#include <YunServer.h>
#include <YunClient.h>
#include <Servo.h>

//comunication server declaration with the Linux side 
YunServer server;

//Servo objects declarations 
Servo myservoL;
Servo myservoR;

//function mode variable (forward, left, right, stop)
int mode; 
//timeout variable to avoid run without commands
int timeout;

//Arduino setup routine
void setup() {
//servo pins declaration

//variables initialization

//set pin13 for debug function

//start Bridge comunication with Linux

void loop() {
  digitalWrite(13, HIGH);
  //read commands from Linux
  YunClient client = server.accept();
   if (client) {
   //if there is a message it tries to decode
  //select actions to do according to current "mode" variable
  if (mode == 1) {
  if (mode == 2) {
  if (mode == 3) {
  if (mode == 4) {
  //strobe alive led
  digitalWrite(13, LOW);
  //slow is better

void process(YunClient client) {
  String command = client.readStringUntil('/');
  if (command == "mode") {
   //if it's a "mode" command 
  if (command == "state") {
   //if it's a "state" command

void modeCommand(YunClient client) {
//change the function mode
  mode = client.parseInt();
  if ( == '/') {
   //set new timeout for the new function mode
    timeout = client.parseInt();
  //answer with current function "mode" and "timeout"

 //answer with current function "mode" and "timeout"
void stateCommand(YunClient client) {

//exec go forward command mode
void gostraight() {
  if (timeout > 0) {
    timeout = timeout -1;
  else {

//exec turn left command mode
void turnleft() {
  if (timeout > 0) {
    timeout = timeout -1;
  else {

//exec turn right command mode
void turnright() {
  if (timeout > 0) {
    timeout = timeout -1;
  else {

//exec stop command mode
void stopmode() {
    timeout = 0;

In the next post I will talk about the web server Linux.

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Saturday, February 1, 2014

Confessions of a FPV pilot. The rover - Part 1

New rules from ENAC (Italian Civil Aviation Authority) seem to forbid the FPV. The situation isn't yet clear. But in meantime...

Like water that seeps into every crevice and find new ways to satisfy his nature I decided after some googling to build a web video controlled rover.

I built something similar some time ago. It was a little rower with three wheels and was the terrestial father of the TZagi plane that I described in the post "Confession of an FPV pilot".
I modified two model servos for continuos rotation and I added a surveillance camera with a 2,4 GHz trasmitter. I linked the video reciver to the TV in my living room and  I drow the rover that was in my garden with an old two channel model transmitter.

I never saw my garden from that point of view. It was a new place. A little planet full of mysteries. There were huge monsters like cats, hens and hedgehog. It was a videogame with which I could lose myself for hours. It was 1997 and I followed with passion the events about Mars Pathfinder project. In those days was born my wish to build a little personal rover.

I know! It is very nasty now and I think I'll have to work hard on design.
I got some parts from my planes and I stole a plastic tray from the kitchen to have a board where place a bunch of components that allow me to develop the software.
The rover has:
This is the project diagram:

In the next post I'm going to describe the software.