TTK4155 Byggern

Lab in TTK4155 – Embedded and Industrial Computer Systems Design

Project

This repository contains the code for the implementation of a physical ping pong machine. It contains the game logic, as well as drivers for all the different components.

In addition to the actual machine implemented in low level C code, the project was set up with a rest API and a simple web frontend. The game could also be played automatically, through the means of computer vision with the OpenCV library. For this, a kalman filter was implemented to track and predict the ping pong ball's future movements. The code for this can be found in the following github repos:

• https://github.com/sigtot/byggern-rest
• https://github.com/sigtot/byggern-frontend
• https://github.com/sigtot/circle-detection
• https://github.com/sigtot/kalman

Node 2 UART Api

The internal state of node2 is simply the reference servo and motor positions for the physical machine.

typedef struct Reference_State {
    int servo_pos;
    int motor_pos;
} Reference_State;

The positions are percentage values ranging from 0 to 100. This global state can be mutated by via a UART api. This is done by sending a string such as

{servo=35&motor=78}

over UART to node2. Both parameters servo and motor are optional, so {servo=35} and {motor=78} are just as valid.

Writing and running tests

Integration tests are found in nodeN/tests/integration

Running tests

Tests are run with the following command:

sh runtest.sh TEST

So, to run for example integration/ir_test.c on node2, run the following command (requires sudo)

./runtest.sh integration/ir_test.c

To run all the tests, instead do

./runall.sh

Writing new tests

Tests should be .c files placed in nodeN/tests/integration or similar. When executing the test, the actual main.c file in nodeN/src will be replaced with the test, and flashed to the node. Therefore, you should write your tests as you would write a main file. As an example, look at the very simple ir_test.c:

#include "parameters.h"
#include <avr/io.h>
#include <stdlib.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "uart.h"
#include "reference_state.h"

#include "ir.h"

int main() {
	UART_Init(MYUBRR);
	fdevopen(*UART_Transmit,NULL);

	printf("Test instruction: Hold the IR emitter up to the photo diode. The test will alert you when the state changes.\n\r");
	ir_init();
	sei();

	int ir_light_received = !Ir_is_blocked();
	printf("%s\n\r", ir_light_received ? "RECEIVING IR LIGHT" : "NOT RECEIVING IR LIGHT");
	while(1) {
		int new = !Ir_is_blocked();
		if (ir_light_received != new) {
			ir_light_received = new;
			printf("%s\n\r", ir_light_received ? "RECEIVING IR LIGHT" : "NOT RECEIVING IR LIGHT");
		}
	}
	return 0;
}