car-chasing killbot [midtermproject]

My project proposal should you choose to accept it is a car-chasing killbot.  It will be used to tail cars then eliminate the target once the target stops the car.  Technically it’s a small-scale automated taillight-chasing trike (see crude sketch).

 

State Diagram (in words…):

  It will start out in CHASE mode where it will follow a moving light target.  It will stop if it senses an obstruction and will back up if it senses the car is reversing towards it.  It will go into KILL mode when the light it is following suddenly goes away without the proximity sensor input changing, which will indicate that the car is now turned off.  It will solenoidally deploy a missile mounted on its back (not in sketchy sketch) towards the car, the trajectory for which will be determined by the proximity (trajectory fixed; bot will move to desired distance).  It will finally go into RUN AWAY mode when the light level suddenly increases (changes are all defined threshold-relative), implying that either the car blew up or there’s cops!

Algorithm:
  Initially I thought Left Sensor HIGH à RUN Right Motor, but possible multiple light sources would mess that up, so I’ve opted to go with Left Sensor LOW à RUN Left Motor.  The bot will aim direct at the light source when the light sensor inputs are equal.  The proximity sensor will keep it from chasing light through glass windows and getting run over by the target car going in reverse to foil attempted murder.

Code Sketch:
  while(state==chase) {
    while(prox>=threshold.prox) {
      follow light // naturally center-aiming
      if(light.prev – light.current > threshold.light1) {state=kill}
    }
    back up
  }
  while(state==kill) {
    from last proximity input, go to specified distance
    deploy missile! // this is in while loop since ultimately i want it to keep shooting
    if(light.current – light.prev > threshold.light2) {state=retreat}
  }
  while(state==retreat) {
    retreat?
  }

Parts List:

- 2x L/Rwheels

- 1x back wheel (castor)

- 2x DC motors

- 3x light sensors

- 1x proximity sensor

- 1x solenoid

- 1x missile

Wiring:

- 2x H-bridges

- 1x power supply (12V?)

- transistors, diodes, resistors

 

Wiring Schematic:

  This is in progress.  I need to figure out (ask) how to supply varying input voltages from an external source…