First successful autonomous run of A.R.T.

December 27th, 2010 § 1 comment

  • First time I made holes in a piece of wood with a Dremel
  • First time I bought tie-wraps in China
  • First time I blew up the fuse for Xindanwei putting everyone in the dark when I tried to solder
  • First time I’ve connected the Vin for an Arduino Dueminalove (instead of the external power header or USB)
  • First time I’ve read values from an infrared sensor (E18-D80NK with a Chinese only datasheet)
  • First time I got an autonomous robot to be, well, autonomous – by myself! (video)
  • [gallery link="file"] It’s neither very nice looking or very impressive when it runs, but I’m still very happy with the results.  I planned something electro-mechanical with a tiny bit of embedded software all by myself (with some help from Niko with the Dremel and Héqíchén / 何琪辰 to buy the tie-wraps!). I planned, executed and… got the results I wanted! The simplistic code that I used:
    const int FORWARD =  2;
    const int REVERSE =  3;
    const int LEFT = 4;
    const int RIGHT =  5;
    const int INFRARED_FORWARD = A0;
    const int INFRARED_REVERSE = A1;
    const int MINIMUM_INFRARED_READING = 500;
    int current_reverse = LEFT;
    int alt_forward = RIGHT;
    char current_state;
    void setup() {
      pinMode(FORWARD, OUTPUT);
      pinMode(REVERSE, OUTPUT);
      pinMode(LEFT, OUTPUT);
      pinMode(RIGHT, OUTPUT);
    char update_state(char state, int reason) {
      char previous_state = current_state;
      if(state != current_state) {
        current_state = state;
      return previous_state;
    void loop(){
        // always check if we can go forward
        int value = analogRead(INFRARED_FORWARD);
        if(value >= MINIMUM_INFRARED_READING) {
            // maybe we were correcting, so check that
            char last_state = update_state('F', value);
            digitalWrite(current_reverse, LOW);
            digitalWrite(REVERSE, LOW);
            if(last_state == 'R') {
              // we just successfully exited a bad loop, turn for a bit for half a second
              digitalWrite(alt_forward, HIGH);
              digitalWrite(FORWARD, HIGH);
              digitalWrite(alt_forward, LOW);
            digitalWrite(FORWARD, HIGH);
        } else {
          // otherwise, still correcting, keep off
          digitalWrite(FORWARD, LOW);
          // we want to try to find an alt path
          int value = analogRead(INFRARED_REVERSE);
          if(value >= MINIMUM_INFRARED_READING) {
            //still have some ability to go backward
            update_state('R', value);
            digitalWrite(current_reverse, HIGH);
            digitalWrite(REVERSE, HIGH);
          } else {
            // whooaah, even backward is not possible, we're stuck
            digitalWrite(current_reverse, LOW);
            digitalWrite(REVERSE, LOW);
            update_state('S', value);
    • Wooden board and tie-wraps work exceptionally well to prototype the physical arrangement
    • Using the breadboard to prototype the electronics also works well
    • The Arduino “Vin” to provide current in the board header works very well (and can seamlessy switch between USB and that without resetting!)
    • Sticking the RF transmitter board directly on the robot and controlling the motors with that from the Arduino works well
    • The LED that comes on when an obstacle is detected by the infrared sensors is very useful for debugging (need to keep that in mind when using other  sensors)
    • It works!
    • Uses Alkaline AA batteries (I want to switch to the exact same Rechargeable NiCad as the car uses)
    • I spent too much time working with Sketchup instead of manually testing the mechanical design first (and then Sketchup)
    • There’s not much around Xindanwei in terms of computer, electronic or small mechanical stores, so I should plan ahead to shop on Beijing road
    • The infrared sensors that I found in the pile of stuff in Xinchejian work, but more like “on/off” sensors (don’t seem to have any linearity in the distance)
    • No bumper (the infrared sensor was crashing into the walls…)
    • Making an obstacle course big enough is annoying
    • I had forgotten to make the holes to attach the sensors (more holes == better)
    • No on/off switch so have to manually remove the connections to turn off power
    • You can never have enough tie-wraps… We only had four at Xinchejian before I bought a pack of 500 for 15RMB (but really, worth about 5RMB)
    • I need to learn how to solder… without blowing fuses…


    § One Response to First successful autonomous run of A.R.T.

    • haixiao.sun说道:

      Wow, That is really wonderful…. now i know who black out the Xindanwei while I am leaving. 🙂 Cheers, Ricky!!!


    邮箱地址不会被公开。 必填项已用*标注

    What's this?

    You are currently reading First successful autonomous run of A.R.T. at 新车间 [XinCheJian].