Saturday, February 13, 2016

Saturday, January 9, 2016

Intel Edison: LED Blinker

Here's a "hello world" test application for Intel® Edison Compute Module. As what the title says, it's just a simple LED blinker task executed by a fast processor.


Below is the tiny module powered by Intel Atom dual-core processor at 500 MHz, with 1 GB DDR3 RAM, 4 GB eMMC Flash, Bluetooth 4.0 and Wi-Fi. It runs Yocto Linux (Linux 3.10.17-poky i686).

Some Intel Edison breakout boards that are shield-like (can be stacked on each other) are also already available on SparkFun. Most useful one is the base block which is used for connecting the Edison module to the host PC via USB. This block has two mini USB ports. The first port is an OTG type and is primarily used for flashing firmware/image of the Edison. The other one is an FTDI-based USB-to-Serial which is used for connecting to a host's serial terminal/console.

Initial configuration requires the Edison module to be connected to a serial terminal, like putty (sample boot log). After configuring the WiFi and the root's password, it is now possible to access the module remotely using ssh connection, just like in the demo video above.

The code below is a simple C++ code for blinking an LED connected at GP14. The code depends on mraa low level library to access the GPIO hardware.
/* intel edison led blink - yus 20150109 */

#include <mraa.hpp>
#include <iostream>

int main()
    mraa::Gpio *gpio = new mraa::Gpio( 36 /*=GP14!*/ );
    if (gpio && gpio->dir(mraa::DIR_OUT)==mraa::SUCCESS)
        std::cout<<"Blinking GP14. Press [CTRL+C] to stop...\n";
        while (1) {
    return -1;

The provided Yocto Linux installed in the Edison already includes a GNU toolchain (GCC 4.9). So the demo code  can be compiled/build inside the Edison itself.

Alternatively, a BASH script can be also used to do a LED blink task.

# select led pin


if [ ! -d "$gpio" ]; then
    echo $pin > /sys/class/gpio/export

echo out > $gpio/direction
echo Blinking GP$pin. Press [CTRL+C] to stop...
while :
    echo 1 > $gpio/value
    sleep 1
    echo 0 > $gpio/value
    sleep 1

Also, for those who are comfortable developing with Arduino IDE, the Arduino IDE also supports Intel Edison. However, you need to check the correct pin mappings if you're going to use boards other than Arduino's Edison kit or Edison breakout board.

Edison Getting Started
Edison GPIO block
Flashing Firmware
mraa low level library

Sunday, June 14, 2015

Sunday, November 30, 2014

AVR32 Stepper Motor

AT32UC3L0128 and L293D interfaced with bipolar (4-wire) stepper motors...

Thursday, July 24, 2014

OpenCV Python: 2048 Game Solver

A sample application of Digit Recognition.
2048 solver algorithm based on term2048-AI

import cv2
import numpy as np
import win32api, win32gui, win32ui, win32con, win32com.client
from PIL import Image, ImageFont, ImageDraw, ImageOps

# create training model based on the given TTF font file
def createDigitsModel(fontfile, digitheight):
    font = ImageFont.truetype(fontfile, digitheight)
    samples =  np.empty((0,digitheight*(digitheight/2)))
    responses = []
    for n in range(10):
        pil_im ="RGB", (digitheight, digitheight*2))
        ImageDraw.Draw(pil_im).text((0, 0), str(n), font=font)
        pil_im = pil_im.crop(pil_im.getbbox())
        pil_im = ImageOps.invert(pil_im) + ".png")

        # convert to cv image
        cv_image = cv2.cvtColor(np.array( pil_im ), cv2.COLOR_RGBA2BGRA)
        gray = cv2.cvtColor(cv_image, cv2.COLOR_BGR2GRAY)
        blur = cv2.GaussianBlur(gray,(5,5),0)
        thresh = cv2.adaptiveThreshold(blur,255,1,1,11,2)

        roi = cv2.resize(thresh,(digitheight,digitheight/2))
        responses.append( n )
        sample = roi.reshape((1,digitheight*(digitheight/2)))
        samples = np.append(samples,sample,0)

    samples = np.array(samples,np.float32)
    responses = np.array(responses,np.float32)
    model = cv2.KNearest()
    return model

class Board(object):
    UP, DOWN, LEFT, RIGHT = 1, 2, 3, 4
    FONT = "font/ClearSans-Bold.ttf"
    def __init__(self, clientwindowtitle):
        self.hwnd = self.getClientWindow(clientwindowtitle)
        if not self.hwnd:
        self.hwndDC = win32gui.GetWindowDC(self.hwnd)
        self.mfcDC  = win32ui.CreateDCFromHandle(self.hwndDC)
        self.saveDC = self.mfcDC.CreateCompatibleDC(), self.ct, right, bot = win32gui.GetClientRect(self.hwnd), =, bot-self.ct += win32api.GetSystemMetrics(win32con.SM_CXSIZEFRAME)
        self.ct += win32api.GetSystemMetrics(win32con.SM_CYSIZEFRAME)
        self.ct += win32api.GetSystemMetrics(win32con.SM_CYCAPTION) += win32api.GetSystemMetrics(win32con.SM_CYSIZEFRAME)*2

        self.saveBitMap = win32ui.CreateBitmap()

        self.tiles, self.tileheight, self.contour = self.findTiles(self.getClientFrame())
        if not len(self.tiles):
        self.digitheight = self.tileheight / 2
        self.digitsmodel = createDigitsModel(self.FONT, self.digitheight)


    def getClientWindow(self, windowtitle):
        toplist, winlist = [], []
        def enum_cb(hwnd, results):
            winlist.append((hwnd, win32gui.GetWindowText(hwnd)))
        win32gui.EnumWindows(enum_cb, toplist)
        window = [(hwnd, title) for hwnd, title in winlist if windowtitle.lower() in title.lower()]
        if not len(window):
            return 0
        return window[0][0]

    def getClientFrame(self):
        self.saveDC.BitBlt((0, 0), (,,
                    self.mfcDC, (, self.ct), win32con.SRCCOPY)

        bmpinfo = self.saveBitMap.GetInfo()
        bmpstr = self.saveBitMap.GetBitmapBits(True)

        pil_img = Image.frombuffer( 'RGB',
            (bmpinfo['bmWidth'], bmpinfo['bmHeight']),
            bmpstr, 'raw', 'BGRX', 0, 1)

        array = np.array( pil_img )
        cvimage = cv2.cvtColor(array, cv2.COLOR_RGBA2BGRA)
        return cvimage

    def findTiles(self, cvframe):
        tiles, avgh = [], 0
        gray = cv2.cvtColor(cvframe,cv2.COLOR_BGRA2GRAY)
        thresh = cv2.adaptiveThreshold(gray,255,1,1,11,2)
        contours, hierarchy = cv2.findContours(thresh.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

        def findBoard(contours): # get largest square
            ww, sqcnt = 10, None
            for cnt in contours:
                x,y,w,h = cv2.boundingRect(cnt)
                if w>ww and abs(w-h)<w/10:
                    ww = w
                    sqcnt = cnt
            return sqcnt

        board = findBoard(contours)
        if board==None:
            print 'board not found!'
            return tiles, avgh, board
        bx,by,bw,bh = cv2.boundingRect(board)
        #cv2.destroyWindow( 'board' )        
        maxh = bh/4
        minh = (maxh*4)/5
        count = 0
        for contour in contours:
            x,y,w,h = cv2.boundingRect(contour)
            if y>by and w>minh and w<maxh and h>minh and h<maxh:
                avgh += h
                count += 1
        if not count:
            print 'no tile found!'
            return tiles, avgh, board

        avgh = avgh / count
        margin = (bh-avgh*4)/5
        for row in range(4):
            for col in range(4):
                x0 = bx + avgh*col + margin*(col+1)
                x1 = x0 + avgh
                y0 = by + avgh*row + margin*(row+1)
                y1 = y0 + avgh
                tiles.append([x0, y0, x1, y1])
        #cv2.destroyWindow( 'tiles' )       
        return tiles, avgh, board
    def getTileThreshold(self, tileimage):
        gray = cv2.cvtColor(tileimage,cv2.COLOR_BGR2GRAY)
        row, col = gray.shape
        tmp = gray.copy().reshape(1, row*col)
        counts = np.bincount(tmp[0])
        sort = np.sort(counts)

        modes, freqs = [], []
        for i in range(len(sort)):
            freq = sort[-1-i]
            if freq < 4:
            mode = np.where(counts==freq)[0][0]

        bg, fg = modes[0], modes[0]
        for i in range(len(modes)):
            fg = modes[i]
            #if abs(bg-fg)>=48:
            if abs(bg-fg)>32 and abs(fg-150)>4: # 150?!
        #print bg, fg
        if bg>fg: # needs dark background ?
            tmp = 255 - tmp
            bg, fg = 255-bg, 255-fg
        tmp = tmp.reshape(row, col)
        ret, thresh = cv2.threshold(tmp,(bg+fg)/2,255,cv2.THRESH_BINARY)        
        return thresh
    def getTileNumbers(self, cvframe):
        numbers = []
        outframe = np.zeros(cvframe.shape,np.uint8)
        def guessNumber(digits):
            for i in range(1,16):
                nn = 2**i
                ss = str(nn)
                dd = [int(c) for c in ss]
                if set(digits) == set(dd):
                    return nn
            return 0
        for tile in self.tiles:
            x0,y0,x1,y1 = tile
            tileimage = cvframe[y0:y1,x0:x1]

            thresh = self.getTileThreshold(tileimage)
            contours,hierarchy = cv2.findContours(thresh.copy(),cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)

            dh = self.digitheight
            digits = []
            for cnt in contours:
                x,y,w,h = cv2.boundingRect(cnt)
                if  h>w and h>(dh*1)/5 and h<(dh*6)/5:
                    roi = thresh[y:y+h,x:x+w]
                    roi = cv2.resize(roi,(dh,dh/2))
                    roi = roi.reshape((1,dh*(dh/2)))
                    roi = np.float32(roi)
                    retval, results, neigh_resp, dists = self.digitsmodel.find_nearest(roi, k=1)
                    digit = int((results[0][0]))
                    string = str(digit)

        return numbers, outframe

    def getWindowHandle(self):
        return self.hwnd

    def getBoardContour(self):
        return self.contour
    def update(self):
        frame = self.getClientFrame()
        self.tilenumbers, outframe = self.getTileNumbers(frame)
        return self.tilenumbers, frame, outframe

    def copyTileNumbers(self):
        return self.tilenumbers[:]

    def getCell(self, tiles, x, y):
        return tiles[(y*4)+x]

    def setCell(self, tiles, x, y, v):
        tiles[(y*4)+x] = v
        return tiles

    def getCol(self, tiles, x):
        return [self.getCell(tiles, x, i) for i in range(4)]

    def setCol(self, tiles, x, col):
        for i in range(4):
            self.setCell(tiles, x, i, col[i])
        return tiles

    def getLine(self, tiles, y):
        return [self.getCell(tiles, i, y) for i in range(4)]

    def setLine(self, tiles, y, line):
        for i in range(4):
            self.setCell(tiles, i, y, line[i])
        return tiles

    def validMove(self, tilenumbers, direction):
        if direction == self.UP or direction == self.DOWN:
            for x in range(4):
                col = self.getCol(tilenumbers, x)
                for y in range(4):
                    if(y < 4-1 and col[y] == col[y+1] and col[y]!=0):
                        return True
                    if(direction == self.DOWN and y > 0 and col[y] == 0 and col[y-1]!=0):
                        return True
                    if(direction == self.UP and y < 4-1 and col[y] == 0 and col[y+1]!=0):
                        return True
        if direction == self.LEFT or direction == self.RIGHT:
            for y in range(4):
                line = self.getLine(tilenumbers, y)
                for x in range(4):
                    if(x < 4-1 and line[x] == line[x+1] and line[x]!=0):
                        return True
                    if(direction == self.RIGHT and x > 0 and line[x] == 0 and line[x-1]!=0):
                        return True
                    if(direction == self.LEFT and x < 4-1 and line[x] == 0 and line[x+1]!=0):
                        return True
        return False

    def moveTileNumbers(self, tilenumbers, direction):
        def collapseline(line, direction):
            if (direction==self.LEFT or direction==self.UP):
                inc = 1
                rg = xrange(0, 4-1, inc)
                inc = -1
                rg = xrange(4-1, 0, inc)
            pts = 0
            for i in rg:
                if line[i] == 0:
                if line[i] == line[i+inc]:
                    v = line[i]*2
                    line[i] = v
                    line[i+inc] = 0
                    pts += v
            return line, pts
        def moveline(line, directsion):
            nl = [c for c in line if c != 0]
            if directsion==self.UP or directsion==self.LEFT:
                return nl + [0] * (4 - len(nl))
            return [0] * (4 - len(nl)) + nl
        score = 0
        if direction==self.LEFT or direction==self.RIGHT:
            for i in range(4):
                origin = self.getLine(tilenumbers, i)
                line = moveline(origin, direction)
                collapsed, pts = collapseline(line, direction)
                new = moveline(collapsed, direction)
                tilenumbers = self.setLine(tilenumbers, i, new)
                score += pts
        elif direction==self.UP or direction==self.DOWN:
            for i in range(4):
                origin = self.getCol(tilenumbers, i)
                line = moveline(origin, direction)
                collapsed, pts = collapseline(line, direction)
                new = moveline(collapsed, direction)
                tilenumbers = self.setCol(tilenumbers, i, new)
                score += pts
        return score, tilenumbers      

# AI based on "term2048-AI"
class AI(object):
    def __init__(self, board):
        self.board = board
    def nextMove(self):
        tilenumbers = self.board.copyTileNumbers()
        m, s = self.nextMoveRecur(tilenumbers[:],3,3)
        return m

    def nextMoveRecur(self, tilenumbers, depth, maxDepth, base=0.9):
        bestMove, bestScore = 0, -1
        for m in range(1,5):
            if(self.board.validMove(tilenumbers, m)):
                score, newtiles = self.board.moveTileNumbers(tilenumbers[:], m)
                score, critical = self.evaluate(newtiles)
                newtiles = self.board.setCell(newtiles,critical[0],critical[1],2)
                if depth != 0:
                    my_m,my_s = self.nextMoveRecur(newtiles[:],depth-1,maxDepth)
                    score += my_s*pow(base,maxDepth-depth+1)
                if(score > bestScore):
                    bestMove = m
                    bestScore = score
        return bestMove, bestScore

    def evaluate(self, tilenumbers, commonRatio=0.25):

        maxVal = 0.
        criticalTile = (-1, -1)
        for i in range(8):
            linearWeightedVal = 0
            invert = False if i<4 else True
            weight = 1.
            ctile = (-1,-1)

            cond = i%4
            for y in range(4):
                for x in range(4):
                    if cond==0:
                        b_x = 4-1-x if invert else x
                        b_y = y
                    elif cond==1:
                        b_x = x
                        b_y = 4-1-y if invert else y
                    elif cond==2:
                        b_x = 4-1-x if invert else x
                        b_y = 4-1-y
                    elif cond==3:
                        b_x = 4-1-x
                        b_y = 4-1-y if invert else y
                    if(currVal == 0 and ctile == (-1,-1)):
                        ctile = (b_x,b_y)
                    linearWeightedVal += currVal*weight
                    weight *= commonRatio
                invert = not invert
            if linearWeightedVal > maxVal:
                maxVal = linearWeightedVal
                criticalTile = ctile

        return maxVal, criticalTile

    def solveBoard(self, moveinterval=500):
        boardHWND = self.board.getWindowHandle()
        if not boardHWND:
            return False
        bx, by, bw, bh = cv2.boundingRect(self.board.getBoardContour())
        x0, x1, y0, y1 = bx, bx+bw, by, by+bh

        shell = win32com.client.Dispatch('WScript.Shell')
        print 'Set the focus to the Game Window, and the press this arrow key:'
        keymove = ['UP', 'DOWN', 'LEFT', 'RIGHT']

        delay = moveinterval / 3 # milliseconds delay to cancel board animation effect
        prev_numbers = []
        while True:
            numbers, inframe, outframe = self.board.update()
            if numbers != prev_numbers:
                numbers, inframe, outframe = self.board.update()
                if numbers == prev_numbers: # recheck if has changed
                prev_numbers = numbers
                move = ai.nextMove()
                if move:
                    key = keymove[move-1]
                    print key
                    cv2.imshow('CV copy',inframe[y0:y1,x0:x1])
                    cv2.imshow('CV out', outframe[y0:y1,x0:x1])
        cv2.destroyWindow( 'CV copy' )
        cv2.destroyWindow( 'CV out' )

board = Board("2048 - Google Chrome")
#board = Board("2048 - Mozilla Firefox")

ai = AI(board)

print 'stopped.'

# open this site with Chrome:
board = Board("2048 - Google Chrome")
ai = AI(board)

demo video:

Solving the Android version of 2048..
Android phone is running a VNC server (vnc server & viewer are both slow!).

python script:

tip: send [touchscreen]swipe event through adb:
adb shell input swipe x1 y1 x2 y2