Scratch pcduino

Port Scratch to pcDuino with
Hardware Support

Overview




Scratch is a tile-based visual programming
environment and toolkit. It lets kids make
games, animated stories, interactive art,
and share with others on the Net.
In this poster, we explain the work needed
to let Scratch have access to Arudino
compatible hardware interface on pcDuino
when Scratch itself runs on pcDuino.

Introduction
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



Scratch is based on squeak ( a type of smalltalk)
virtual machine.
Scratch provides a mechanism to call host API,
named plugin. Through plugin, Scratch can access
devices, such as camera, sound, on host.
pcDuino already implemented Arduino style API (in
C/C++), so the key is to pacakge pcDuino’s
Arduino-ish API into a form of plugin.

UI




Scratch uses block to organize the programming
elements. Currently, there are 8 blocks.
We add a new block ‘hardware’ to hold the new
elements.

Hardware functions implemented


A portion of pcDuino hardware interface is implemented:




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GPIO 0-23: Set input/output mode, high/low output signal level,
Read Status
PWM5-6: Set the output frequency, duty cycle, turn off PWM
ADC0-5: Read the voltage level

Referring to the UI, the following items are implemented:
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
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set pin (0-23) to (INPUT/OUTPUT) mode
set pin (0-23) to (HIGH/LOW) level
pin (0-23) level is (HIGH/LOW)?
Voltage(mV) of pin (A0-A5)
set pwm (5/6) (781/520/390/260/195) Hz (0-256) step
stop pwm (5/6)

Add a new block “Hardware”


Open system browser in squeak, find method
‘blockSpecs’ in class Scratch-Objects ->
ScratchSpriteMorph -> block specs.

Add a new block “Hardware”
The symbol after % is the input variable. It needs to be
declared in Scratch-Blocks -> CommandBlockMorph -> private ->
uncoloredArgMorphFor. We find a symbol that is not used, and
add our own:

Parameters Enumeration in hardware
block


The format of blockSpec is as following:

(‘block text’#identifier#selector ‘default’
‘values’)

The one after % in ‘block test’ is the input
parameters, we need to implement the following:

%A
#pinModeNames INPUT/OUTPUT

%B
#pinLevelNames HIGH/LOW

%E
#analogPinNames A0-A5

%F
#digitalPinNames
0-23

%G
#pwmPinNames
5/6

%j
#pwmPinFreqs
781/520/390/260/195

%J
#pwmPinLevels
0-256

Calling Method in Hardware Block





# selector in blockSpec is the corresponding calling method. We
need to implement the following methods:

pinMode:to:

digitalWrite:to:

digitalRead:is:

analogReadVoltage:

analogSet:freqTo:stepTo:

analogStop:
All the above methods eventually need to be implemented through
hardware plugin which is implemented in C/C++.
We need to define the interface to hardware plugin.

Calling Method in Hardware
Block


Open system-Browser, and create HardwarePlugin->Primtives Class, and add the
following methods:
primPinMode: pin to: mode
"This is the call to the pinMode primitive."
<primitive: 'primPinMode' module: 'HardwarePlugin'>
self primitiveFailed
primDigitalRead: pin
"This is the call to the digitalRead primitive."
<primitive: 'primDigitalRead' module: 'HardwarePlugin'>
primDigitalWrite: pin to: level
"This is the call to the digitalWrite primitive."
<primitive: 'primDigitalWrite' module: 'HardwarePlugin'>

Block
primAnalogReadVoltage: pin
"This is the call to the analogReadVoltage primitive."
<primitive: 'primAnalogReadVoltage' module: 'HardwarePlugin'>

primAnalogSet: pin freqTo: freq stepTo: step
"This is the call to the analogSet primitive."
<primitive: 'primAnalogSet' module: 'HardwarePlugin'>
primAnalogWrite: pin to: level
"This is the call to the analogWrite primitive."

<primitive: 'primAnalogWrite' module: 'HardwarePlugin'>

Block

Use primPinMode as the example, it will eventually call
function ‘primPinMode’in scratch HardwarePlugin.so to
set the mode of GPIO pin as instructed in <primitive:
'primPinMode' module: 'HardwarePlugin'>

Block
We define the interface in Scratch-Objects ->
ScratchSpriteMorph -> hardware ops instance:
pinMode: pin to: mode
| p m |
p := pin asNumber.
Transcript show: p.
mode = 'INPUT' ifTrue: [ m := 0 ].
mode = 'OUTPUT' ifTrue: [ m := 1 ].
HardwarePlugin primPinMode: p to: m.
digitalRead: pin is: level
| p ret |
p := pin asNumber.
ret := HardwarePlugin primDigitalRead: p.
level = 'HIGH' ifTrue: [ ^ ret ].
^ ret not.
digitalWrite: pin to: level
| p l |
p := pin asNumber.
Transcript show: p.
level = 'LOW' ifTrue: [ l := 0 ].
level = 'HIGH' ifTrue: [ l := 1 ].
HardwarePlugin primDigitalWrite: p to: l.

Block
analogReadVoltage: pin
| p |
pin = 'A0' ifTrue: [ p := 0 ].
pin = 'A1' ifTrue: [ p := 1 ].
pin = 'A2' ifTrue: [ p := 2 ].
pin = 'A3' ifTrue: [ p := 3 ].
pin = 'A4' ifTrue: [ p := 4 ].
pin = 'A5' ifTrue: [ p := 5 ].
^ HardwarePlugin primAnalogReadVoltage: p.

analogSet: pin freqTo: freq stepTo: step
| p f s |
p := pin asNumber.
f := freq asNumber.
s := step asNumber.
HardwarePlugin primAnalogSet: p freqTo: f stepTo: s.
analogStop: pin
| p |
p := pin asNumber.
HardwarePlugin primAnalogWrite: p to: 0.

Implement HardwarePlugin
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



We can refer to the code of camera.
The key is to implement setInterpreter
and the functions primXXX used in
Primitives-Plugins->HardwarePlugin>primtives.
The functions pinMode, digitalRead,
digitalWrite, and analogWrite are
already implemented in libarduino of
pcDuino. We can call them directly.

DLLEXPORT void primPinMode(void) {
int pin = interpreterProxy->stackIntegerValue(1);
int mode = interpreterProxy->stackIntegerValue(0);
pinMode(pin, mode);
}
DLLEXPORT void primDigitalWrite(void) {
int level = interpreterProxy->stackIntegerValue(0);
digitalWrite(pin, level);
}
DLLEXPORT int primDigitalRead(void) {
int level = digitalRead(pin);
interpreterProxy->pop(1);
interpreterProxy->pushBool(level != 0);
return 0;
}

DLLEXPORT int primAnalogReadVoltage(void) {
int level = analogReadVoltage(pin);
interpreterProxy->pop(1);
interpreterProxy->pushInteger(level);
return 0;
}
DLLEXPORT void primAnalogWrite(void) {
analogWrite(pin, level);
}
DLLEXPORT void primAnalogSetFreq(void) {
int freq = interpreterProxy->stackIntegerValue(0);
analogSetFreq(pin, freq);
}
DLLEXPORT void primAnalogSet(void) {
int freq = interpreterProxy->stackIntegerValue(1);
analogSetFreq(pin, freq);
analogWrite(pin, level);

DLLEXPORT int setInterpreter(struct VirtualMachine* anInterpreter)
{
int ok;
interpreterProxy = anInterpreter;
ok = interpreterProxy->majorVersion() == VM_PROXY_MAJOR;
if (ok == 0) {
return 0;
}
ok = interpreterProxy->minorVersion() >= VM_PROXY_MINOR;
return ok;
}

Programming under Ubuntu (linux)

Arduino style programming ( C )
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Two flavors
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Command line
IDE

C Command line
Setup (one time)
If not already done, set up git. Do this using the command:
ubuntu@ubuntu:~$ sudo apt-get install git

Make sure you’re in your home folder by typing
ubuntu@ubuntu:~$ cd
ubuntu@ubuntu:~$ pwd
/home/Ubuntu
Now download the distribution from github by typing
ubuntu@ubuntu:~$ git clone https://github.com/pcduino/c_enviroment

C Command line
Change into the c_enviroment folder:

ubuntu@ubuntu:~$ cd c_enviroment
ubuntu@ubuntu:~/c_enviroment$ ls
Makefile hardware libraries output sample
Now run make to make the libraries and the examples with the following command:
ubuntu@ubuntu:~/c_enviroment$ make
Make[1]: Leaving directory `/home/ubuntu/c_enviroment/sample'
The resulting binary files are found in the output/test folder
ubuntu@ubuntu:~/c_enviroment$ cd output/test
ubuntu@ubuntu:~/c_enviroment/output/test$ ll
total 660
drwxrwxr-x 2 ubuntu ubuntu 4096 Apr 27 06:59 ./
drwxrwxr-x 3 ubuntu ubuntu 4096 Apr 27 06:49 ../
-rwxrwxr-x 1 ubuntu ubuntu 13868 Apr 27 06:58 adc_test*
-rwxrwxr-x 1 ubuntu ubuntu 28284 Apr 27 06:58 adxl345_test*
-rwxrwxr-x 1 ubuntu ubuntu 14209 Apr 27 06:58 interrupt_test*
-rwxrwxr-x 1 ubuntu ubuntu 13726 Apr 27 06:58 io_test*
-rwxrwxr-x 1 ubuntu ubuntu 13712 Apr 27 06:59 linker_button_test*
-rwxrwxr-x 1 ubuntu ubuntu 13907 Apr 27 06:59 linker_buzzer_test*
-rwxrwxr-x 1 ubuntu ubuntu 13689 Apr 27 06:59 linker_hall_sensor_test*
-rwxrwxr-x 1 ubuntu ubuntu 13760 Apr 27 06:59 linker_joystick_test*
-rwxrwxr-x 1 ubuntu ubuntu 13769 Apr 27 06:59 linker_led_bar_test*
-rwxrwxr-x 1 ubuntu ubuntu 13690 Apr 27 06:59 linker_led_test*
-rwxrwxr-x 1 ubuntu ubuntu 14290 Apr 27 06:59 linker_light_sensor_test*
……

C Command line
To view the contents of a sample sketch, (this
example we’ll look at the contents of
linker_led_test.c) type:
ubuntu@ubuntu:~/c_enviroment/sample$ cat
linker_led_test.c
/*
* LED test program
*/
#include <core.h>
int led_pin = 1;
void setup()
{
if(argc != 2){
goto _help;
}
led_pin = atoi(argv[1]);
if((led_pin < 0) || (led_pin > 13)){
goto _help;
}
pinMode(led_pin, OUTPUT);
return;
_help:
printf("Usage %s LED_PIN_NUM(0-13)n", argv[0]);
exit(-1);
}

void loop()
{
digitalWrite(led_pin, HIGH); // set the
LED on
delay(1000); // wait for a second
digitalWrite(led_pin, LOW); // set the LED
off
delay(1000); // wait for a second
}

Creating Your Own Sketch
ubuntu@ubuntu:~/c_enviroment/sample$ nano button_led.c
An empty nano screen should appear.
Copy and paste the following code into it. (Remember to paste in nano at the cursor,
just right click the mouse button).
#include <core.h> // Required first line to run on pcDuino
int ledPin = 8;
int buttonPin = 7;
// variables will change:
int buttonState = 0; // variable for reading the pushbutton status
void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop(){
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed.
// if it is, the buttonState is HIGH:
if (buttonState == HIGH) {
// turn LED on:
digitalWrite(ledPin, HIGH);
}
else {
// turn LED off:
digitalWrite(ledPin, LOW);
}
}

Modify the Makefile and Compile
ubuntu@ubuntu:~/c_enviroment/sample$ nano Makefile
You will see a section that lists all the OBJS something like:
OBJS = io_test adc_test pwm_test spi_test adxl345_test serial_test liquidcrystal_i2c
liquidcrystal_spi interrupt_test tone_test
OBJS += linker_led_test linker_potentiometer_test linker_tilt_test linker_light_sensor_test
linker_button_test
OBJS += linker_touch_sensor_test linker_magnetic_sensor_test linker_temperature_sensor_test
linker_joystick_test
OBJS += linker_rtc_test linker_sound_sensor_test linker_buzzer_test linker_hall_sensor_test
linker_led_bar_test linker_relay_test
OBJS += pn532_readAllMemoryBlocks pn532readMifareMemory pn532readMifareTargetID
pn532writeMifareMemory


We’re going to add a line to the end of this with the name of the
scketch we just created:
OBJS += button_led
Save the file and exit nano using <CTRL>X with a y and <enter>.

We now run make by typing:
ubuntu@ubuntu:~/c_enviroment/sample$ make
You should see a whole bunch of text with the end being:
button_led.c -o ../output/test/button_led ../libarduino.a
If all went well, you can go to the output/test folder and find your executable you have created:
ubuntu@ubuntu:~/c_enviroment/sample$ cd ../output/test/
ubuntu@ubuntu:~/c_enviroment/output/test$ ll
total 676
drwxrwxr-x 2 ubuntu ubuntu 4096 Apr 27 07:51 ./
drwxrwxr-x 3 ubuntu ubuntu 4096 Apr 27 06:49 ../
-rwxrwxr-x 1 ubuntu ubuntu 13868 Apr 27 07:51 adc_test*
-rwxrwxr-x 1 ubuntu ubuntu 28284 Apr 27 07:51 adxl345_test*
-rwxrwxr-x 1 ubuntu ubuntu 13668 Apr 27 07:51 button_led*
…..(not showing rest of listing here)


Run Your Sketch

To run it, once you have wired up a switch and led to the right pins, type:

ubuntu@ubuntu:~/c_enviroment/output/test$ ./button_led
To stop the program, <Ctrl>C
A Quick Re-Cap

Add #include <core.h> to the top of your sketch.
Create your sketch in the samples folder (if your familiar with linux,
makefiles, and compiling code, you could set up your own)
Add the filename to the Makefile in the samples folder in the OBJS section
without the .c
Run make
Run the executable from the output/test folder.
You can introduce command line arguments into your sketch to make it more
transportable.

Python
ubuntu@ubuntu:~/python-pcduino/Samples/blink_led$ more blink_led.py
#!/usr/bin/env python
# blink_led.py
# gpio test code for pcduino ( http://www.pcduino.com )
#
import gpio
import time
led_pin = "gpio2"
def delay(ms):
time.sleep(1.0*ms/1000)
def setup():
gpio.pinMode(led_pin, gpio.OUTPUT)
def loop():
while(1):
gpio.digitalWrite(led_pin, gpio.HIGH)
delay(200)

OpenCV
def process(infile):
image = cv.LoadImage(infile);
if image:
faces = detect_object(image)

im = Image.open(infile)
path = os.path.abspath(infile)
save_path = os.path.splitext(path)[0]+"_face"
try:
os.mkdir(save_path)
except:
pass
if faces:
draw = ImageDraw.Draw(im)
count = 0
for f in faces:
count += 1
draw.rectangle(f, outline=(255, 0, 0))
a = im.crop(f)
file_name =
os.path.join(save_path,str(count)+".jpg")
#
print file_name
a.save(file_name)
drow_save_path =
os.path.join(save_path,"out.jpg")
im.save(drow_save_path, "JPEG", quality=80)
else:
print "Error: cannot detect faces on %s" %
infile
if __name__ == "__main__":
process("./opencv_in.jpg")

OpenCV
#!/usr/bin/env python
#coding=utf-8
import os
from PIL import Image, ImageDraw
import cv
def detect_object(image):
grayscale = cv.CreateImage((image.width, image.height), 8, 1)
cv.CvtColor(image, grayscale, cv.CV_BGR2GRAY)
cascade = cv.Load("/usr/share/opencv/haarcascades/haarcascade_frontalface_alt_tree.xml")
rect = cv.HaarDetectObjects(grayscale, cascade, cv.CreateMemStorage(), 1.1, 2,
cv.CV_HAAR_DO_CANNY_PRUNING, (20,20))
result = []
for r in rect:
result.append((r[0][0], r[0][1], r[0][0]+r[0][2], r[0][1]+r[0][3]))
return result

Cloud 9 IDE




Cloud9 IDE is an online development environment
for Javascript and Node.js applications as well
as HTML, CSS, PHP, Java, Ruby and 23 other
languages.
You're programming for the web, on the web.
Teams can collaborate on projects and run them
within the browser. When you're finished,
deploy it—and you're done!

Scratch

$sudo apt-get install pcduino-scratch

Home Automation：IP controllable LED


Many users are asking if the hardware part can be
programmed together with the Ubuntu linux?


Sure. This is the beauty of pcDuino. The Arduino compatible hardware is a native part
of the OS.



pcDuino includes Ethernet port, USB Wifi dongle, so there is no
need for Ethernet shield, Ethernet shield , USB host shield, MP3
shields and so on.

Now, we are going to implement a TCP/IP
socket server on pcDuino to listen to the
data coming from client.
When it
turn on
it will
receive

receives character ’O', it will
the LED, and when it receives ‘F”,
turn on the LED. No actions if
something else.

Home Automation：IP controllable LED
#include “sys/socket.h”
#include “netinet/in.h”
#include “arpa/inet.h”
#include
“sys/types.h”

void loop()
{
n = read(connfd, sendBuff, strlen(sendBuff) );

int led_pin = 2;
int listenfd = 0, connfd = 0;
int n;
struct sockaddr_in serv_addr;
char sendBuff[1025];
time_t ticks;

if(n>0)
{
if(sendBuff[0]=='O') digitalWrite(led_pin,
HIGH); // set the LED on
if(sendBuff[0]=='F') digitalWrite(led_pin,LOW);
// set the LED off
}
}

void setup()
{
led_pin = 2;
pinMode(led_pin, OUTPUT);
listenfd = socket(AF_INET, SOCK_STREAM, 0);
memset(serv_addr, '0', sizeof(serv_addr));
memset(sendBuff, '0', sizeof(sendBuff));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(5000);

bind(listenfd, (struct sockaddr*) serv_addr, sizeof(serv_addr));
listen(listenfd, 10);
connfd = accept(listenfd, (struct sockaddr*)NULL, NULL);
}

Two flavors to program under Android


There are two flavors to program under
Android:



Command line
QT5 GUI

QT5 GUI

We can copy the apk though pcDuino OTG or
SD card to pcDunio and install it there.

WiFi Real-time Video Surveillance
remote control robot

Steps to Assemble Rover







Turn pcDuino into aWiFi AP
Install video stream server
Motor driver shield
TCP/IP Communication
Android APK

Scratch pcduino

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