View source for Project:1-web-interfaces-for-rc-vehicles

{{ProjectDetails|ProjectTitle=Projects/1-web-interfaces-for-rc-vehicles}}

[[Projects]]

[[File:Car+battery+charger.jpg|300px|thumb|right|Photo of the r/c car, it's battery and it's charger.]]

==Aim==
Drive a r/c car in as near realtime as possible via a webinterface with a driver's POV wireless video feed. 

==Current Implementation Status / Operator's Log==
===19/11/10===
*The car is working via IRC. Use ?board car1 or ?board car2 or ?board car3 etc
*Numbers 1 to 8 represent the different control characters available (see below for a breakdown of the 'sauce code').
*The battery is quite old and could do with replacing.

==Who?==
[[User:samthetechie]]

[[User:lamda25]]

[[User:ms7821]]

Special thanks to Chris Brooking.

==What?==
r/c car + arduino + IRC + Python + webcams everywhere = awesome internet happy fun time.

1. Next time you are bored and in IRC have a look at the main webcam [http://hack.rs:8001]

2. Ask someone currently in the space very nicely if they wouldn't mind plugging in the battery and turning on the r/c car and placing it in view of the webcam.

3. Then have a chat with robonaut with /msg robonaut ?board car5. If everything went to plan the car should have just gone forwards a bit.

4. For the current full set of commands please refer to the table below:

===Commands===
{| class="wikitable"
|- style="background-color:#999999;"
! Command
! Result
|-
| ?board car1
| Drive forward and turn left.
|-
| ?board car2
| Drive forward and turn right.
|-
| ?board car3
| Drive backward and turn left.
|-
| ?board car4
| Drive backward and turn right.
|-
| ?board car5
| Drive forward.
|-
| ?board car6
| Drive backward.
|-
| ?board car7
| Turn wheels left (not latching, implemented only for testing).
|-
| ?board car8
| Turn wheels right (not latching, implemented only for testing).
|-
|}

===Calibration===
*Movement Timing Calibration Values
 #define FWD_TURN_TIME 1000
 #define BACK_TURN_TIME 1000
 #define DRIVE_TIME 1000

[[File:Arduino+control.jpg|300px|thumb|right|The arduino and the r/c car's controller.]]
===Arduino Shield Pinout===
*Arduino Digital I/O pins
 #define CAR_FWD 9       //White Cable
 #define CAR_BACK 11     //Black Cable
 #define CAR_LEFT 8      //Brown Cable
 #define CAR_RIGHT 10    //Blue  Cable

There is also a digital ground pin (it is a black cable and it is on its own) attached to a chocolate block in order to allow sharing of the digital ground with other circuits on that arduino.

===Sauce Code===
The source is currently in an IF loop in the [https://github.com/solexious/NotifyBoard Solexious' NotifyBoard arduino sketch]. Note: request upstream pull to github from local git repo on babbage or lovelace.
    if (strstr(inString,"car")) {
      if (strlen(inString) > 3) {
        char car_cmd = inString[3];
          switch (car_cmd){
          case '1':
            digitalWrite(CAR_LEFT, HIGH);
            digitalWrite(CAR_FWD, HIGH);
            delay(FWD_TURN_TIME);
            digitalWrite(CAR_LEFT, LOW);
            digitalWrite(CAR_FWD, LOW);
            break;
          case '2':
            digitalWrite(CAR_RIGHT, HIGH);
            digitalWrite(CAR_FWD, HIGH);
            delay(FWD_TURN_TIME);
            digitalWrite(CAR_RIGHT, LOW);
            digitalWrite(CAR_FWD, LOW);
            break;
          case '3':
            digitalWrite(CAR_LEFT, HIGH);
            digitalWrite(CAR_BACK, HIGH);
            delay(BACK_TURN_TIME);
            digitalWrite(CAR_LEFT, LOW);
            digitalWrite(CAR_BACK, LOW);
            break;
          case '4':
            digitalWrite(CAR_RIGHT, HIGH);
            digitalWrite(CAR_BACK, HIGH);
            delay(BACK_TURN_TIME);
            digitalWrite(CAR_RIGHT, LOW);
            digitalWrite(CAR_BACK, LOW);
            break;
          case '5':
            digitalWrite(CAR_FWD, HIGH);
            delay(DRIVE_TIME);
            digitalWrite(CAR_FWD, LOW);
            break;
          case '6':
            digitalWrite(CAR_BACK, HIGH);
            delay(DRIVE_TIME);
            digitalWrite(CAR_BACK, LOW);                  
            break;
          case '7':
            digitalWrite(CAR_LEFT, HIGH);
            delay(DRIVE_TIME);
            digitalWrite(CAR_LEFT, LOW);
            break;
          case '8':
            digitalWrite(CAR_RIGHT, HIGH);
            delay(DRIVE_TIME);
            digitalWrite(CAR_RIGHT, LOW);                  
            break;
        }
      }
    }

==Where?==
London Hackspace Lab 24: http://london.hackspace.org.uk/

==Why?==
Driving a car remotely over the internet is fun. This is not however funny in the case of a real car...

==How?==
Four digital I/Os from the arduino (11,10,9,8), each of which are connected to the gate of an NPN transistor to handle about 30mA switching current, simulate the pressing of the four push-to-make contact switches on a simple r/c car remote control. digitalWrite(pinX, HIGH); results in a pressed state and digitalWrite(pinX, LOW); results in an unpressed state. This effectively gives a digitally-controlled forward, backward, left and right switch for the remote control car. This concept can be applied to any cheap remote-controlled toy.

==Development Milestones==
<del>1. Working via IRC using ?board car<command number> in 'less than realtime'.</del> DONE

2. Working via a webpage babbage:80XX or /var/www/rcv or something like that in 'near realtime'.

3. Low quality but high refresh rate on-board wireless camera to suit real-time control interface.