Special Feature(s)
Team Bravo was awarded the Best Special Feature Award because of our in-depth special feature a wireless joystick controller accompanied with other special features, the autmatic headlights and direction indicator.
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Joystick Controller
Team Bravo's main special feature is a Joystick Controller which is used to control the movement of the micromouse around. The remote controller was built constittuting a Joystick Module, Arduino Uno board and a RF (radio frequency) transmitter.
It was first designed to change the speed and direction of the micromouse using the joystick but the RF receiver on the micromouse is open source which receives almost all the signals around the area of the micromouse which made speed controlling hard to complete.
The controller was coded by sending out only one letter from the controller for each direction rather than sending a bunch of codes to let the micromouse decode since there are always some data loss between the transmitter and receiver. Each letter sent out to the RF receiver on the micromouse suggested a movement which corresponds to the direction of the joystick.
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Automatic Headlight
Another special feature added to the micromouse was an automatic headlight which turns on in dark places and turns off in bright areas. Since it is an headlight, ten mega-white LEDs arranged in parallel and in an hexagonal shape were used to design the headlights. A NPN BC547C Bipolar Transistor was used to amplify the current flowing through the parallel arranged LEDs for maximum brightness. The white line sensor was improvised to get an output voltage. light dependent resistor whose resistance changes with response to brightness and darkness was used take readings and conclude on a threshold voltage of 3.5V.
The white line sensor circuit was simplified to the circuit above. The output voltage was fed into Port B4 an analogue converter which makes a decision to turn on Port A7 if the output voltage is greater that 3.5V. The base of the bipolar transistor was connected to Port A7 which supplies voltage to the base and turns on the base-emitter and amplifies the collector current. The collector was connected to a power supply pin and the emitter to a ground pin.
The circuit above shows the arrangement of the mega white LEDs substituted with yellow LEDs in MultiSim. The circuit was built on a veroboard as shown below.
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Light Direction Indicator
The light direction indicators was designed to illuminate red LEDs while indicating direction light with respect to the movement of the micromouse like the indcators of a motor vehicle. This was designed as part of the special feature. Three indicators were designed for the forward, backward, left and right movements on the micromouse. Red LEDs which has a 1.8V were chosen to be used for all the light indicators to ensure that all indicators lighted up properly when in use.
The circuit above was used by each side indication. Three LEDS connected in parallel were used for each side indication. Resistor values of three hundred and twenty ohms (320Ω) were used for each of the three parallel connected LEDS indicator sides. For each side of the four direction indicators, it had one of its ends connected in to a Port on the micro controller which turns it on. The ports to which the direction indicators were connected to were; left side to the Port A2, right side to the Port A1, front or forward side to the Port A6 and finally the back or backward side to the Port A0. The ports were turned on in the code in the turn right, turn left, forward and reverse functions. The light indicators were also given a common ground on its veroboard circuitry, which was then connected to the one of the ground ports on the microcontroller.
