In the lab, we pick a simple algorithm to simulate the behavior of “cohesion”. Steps are as follow:

1. Trigger

We have five micro:bit as operating micro:bit in a square and another one micro:bit as controller. Each operating micro:bit will join a radio group with the controller. Once the controller micro:bit gives out a trigger to all operating micro:bit, they will switch to the mode “cohesion” and begin to move to a certain point.

2. Calculate

Each operating micro:bit will stick to a different individual mark. The computer vision system will determine the coordinates of each mark. After we get the coordinates of all five micro:bit, we will calculate the coordinates of the point which is the average point to all five micro:bit. Then we will sent the current position coordinates and average point position coordinates to five operating micro:bit through controller micro:bit.

3. Display

After five operating micro:bit get the coordinates, they will calculate the direction they need to head to. Then they will show an arrow towards the place the mark is on there 5×5 LED.

4. Move

Operating micro:bit will move towards or away from the marker. After each move, we will get the new location coordinates of the operating micro:bit and send them through controller micro:bit. The operating micro:bit will then automatically calculate the distance away from the average point and compare it with previous distant. If they move towards the marker (distant is smaller), they show a happy face on their screen. If they move away from the marker (distant is larger), they show a sad face. Once they are in the position they wanted to be, their screen displays something else (a square or a circle, for example).

Code:

Important Variables:

previous_distance 

current_distance

cur=(x_cur, y_cur)

des=(x_des, y_des)

Logic:

void loop{
current_distance=dist(des,cur);

if (previous_distance>current_distance){
display(HAPPY);
}else{
display(SAD);
}

previous_distance =dist(des,cur);

The logic of our algorithm is not hard to figure out. The only problem we need to solve is how to repeatedly send out coordinates (information) from the controller micro:bit.