Published May 28, 2018 © LGPL

PHPoC - Scratch Programming 102

Let's continue to "scratch" with PHPoC. Check out some basic tutorials in this Scratch programming with PHPoC.

BeginnerFull instructions provided1 hour864

Things used in this project

Hardware components

PHPoC Blue

Servos (Tower Pro MG996R)

Rotary angle sensor

PHPoC PWM & Sensor Expansion Board

Optional

Software apps and online services

Scratch Editor 2.0 Offline

Node.js

Story

Previously, I have presented about how to connect Scratch with PHPoC IoT board and make a simple remote control for spider robot. If you don't know about Scratch or Scratch programming with PHPoC, you can take a look at my last project here.

In this project, I want to show how to make PHPoC-based projects with Scratch blocks, so I am going to continue with some simple tutorials: control onboard LED, control servo motor, read the value from rotary angle sensor. Nothing makes it easier to understand than having examples, right? I also made some source code modifications in helper app and extension file. Let's continue our course, Scratch programming with PHPoC 102 :D.

I. Demo

II. Connect Scratch with PHPoC:

This step is already introduced in my previous project. As I presented in section III.3, Step 3 of Connect Scratch with PHPoC, a helper app needs to be run in order to communicate between PHPoC board and Scratch Editor.

Set up connection between Scratch and PHPoC

For demonstration purpose, I wrote a simple helper app using Node.js. First we need to install Node.js. Then, browse to Scratch Demo folder, and run the following command in the command line:

npm install

This command is used to install Node.js dependencies.

In addition, I made a simple Windows-service-based helper app. It means that you can run the helper app as a Windows service, instead of launching it from command line every single time.

In the command line, just enter:

npm setup-service

This command is used to install helper app as a Windows service. Select OK if there are some confirmation popups. After the successful installation, you can see this in Services window:

Services window

Of cause, if you don't want to make it a startup Windows service, you can use the following command to start the helper app for each run-time:

npm start

III. Scratch programming tutorial:

I created Scratch projects based on available tutorials for PHPoC board. You can refer to those tutorials for more detail:

Control onboard LED: http:// https://forum.phpoc.com/articles/tutorials/331-led-controlling-led-from-webpage-with-image

uio_onboard_led

Here, PHPoC-specified blocks, Scratch's Events and Looks blocks are used to control an onboard LED. You just need to click on the LED icon to switch the onboard LED.

Rotary angle sensor: https://forum.phpoc.com/articles/tutorials/342-rotary-angle-sensor-how-to-use-rotary-angle-sensor

rotary_angle_sensor

In this example, you can see how to read and display the analog data, using Scratch' s Events, Data, Looks, Control, Operators and PHPoC-specified blocks.

Control servo motor: https://forum.phpoc.com/articles/tutorials/350-servo-motor-controlling-servo-motor-via-websocket-with-graphic-ui

servo_motor

This example shows you how to program Scratch to control the servo via UI interaction. Servo motor will rotate based on your on-click direction. As you can see, Scratch' s Events, Data, Looks, Motion, Control, Operators, PHPoC-specified blocks are used.

IV. Source Code

Source code includes:

helper_app_main.js: Helper app implementation.

helper_app_installer.js: Helper app installer file (for making Windows-service).

PHPoC_demo_extension_en.s2e : Hardware extension file for PHPoC, in JSON format

task0.php: This file needs to be loaded and run on PHPoC board.

uio_onboard_led.sb2 : Project with onboard LED

rotary_angle_sensor.sb2 : Project with rotary angle sensor

servo_motor.sb2 : Project with servo motor

You can get the source code here: Download link

Scratch 3.0 is incoming, and there are also some other platforms similar to Scratch. It would be a lot of fun trying to connect IoT board to those platforms and enjoy graphical programming. Hope you guys find it interesting. Cheers :D

task0.php

<?php

if(_SERVER("REQUEST_METHOD"))
	exit; // avoid php execution via http request

include_once "/lib/sd_340.php";
include_once "/lib/sn_tcp_ws.php";

define("WS_ID", 0);
define("WS_PATH", "scratch_test");

// Define output servo motor
define("PWM_PERIOD", 20000); // 20000us (20ms)
define("WIDTH_MIN", 600);
define("WIDTH_MAX", 2450);


$uio_list = array(8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21);
for($i=0; $i<12;$i++){
    uio_setup(0, $uio_list[$i], "in_pu"); 
}

uio_setup(0, 30, "out high");
uio_setup(0, 31, "out high");

function servo_set_angle($pin, $angle){
	$angle= 90 - $angle;
	if($angle < 0)
		$angle = 0;
	if($angle > 180)
		$angle = 180;
	$width = WIDTH_MIN + (int)round((WIDTH_MAX - WIDTH_MIN) * $angle / 180.0);
	if(($width >= WIDTH_MIN) && ($width <= WIDTH_MAX))
		ht_pwm_width(0, $width, PWM_PERIOD);
}

ws_setup(WS_ID, WS_PATH, "csv.phpoc");
$rwbuf = "";

while(1)
{
	if(ws_state(WS_ID) == TCP_CONNECTED)
	{
		$rlen = ws_read_line(WS_ID, $rwbuf);

		if($rlen)
		{
			$cmd = explode("/",$rwbuf);
			switch($cmd[1]){
			case "dW":
				$pin = (int)$cmd[2];
                uio_setup(0, $pin, "out high");
				if ($cmd[3] == "LOW")
					uio_out(0, $pin, LOW);			
				else
					uio_out(0, $pin, HIGH);
				break;
			case "lW":
				$pin = (int)$cmd[2]+29;
				echo $pin,"\r\n";
				if ($cmd[3] == "on")
					uio_out(0, $pin, LOW);			
				else
					uio_out(0, $pin, HIGH);
				break;
			case "svW":
				ht_pwm_setup((int)$cmd[2], (WIDTH_MIN + WIDTH_MAX) / 2, PWM_PERIOD, "us");
			    servo_set_angle((int)$cmd[2], (int)$cmd[3]);
				break;
			case "dR":
				uio_setup(0, (int)$cmd[2], "in_pu"); 
				break;
			case "poll":
				$ret = "";					
                for($i=0; $i<12;$i++){
					$pin = $uio_list[$i];
					$d_in = uio_in(0, $pin);
					$ret = $ret."dR/".(string)$pin." ".(string)$d_in."\n";
				}
				for($pin=0; $pin<=5;$pin++){
					adc_setup(0, $pin);
					$adc_in = adc_in(0, 30);
					$ret = $ret."aR/".(string)$pin." ".(string)$adc_in."\n";
				}
				ws_write(0, $ret);			
				usleep(200000);
				break;
			case "reset_all":
                for($i=0; $i<12;$i++){
					uio_setup(0, $uio_list[$i], "in_pu"); 
				};			
                uio_out(0, 30, HIGH);
                uio_out(0, 31, HIGH);    
				break;				
			
			}			
		}
	}
	
}
 
?>

Credits

Homer

17 projects • 46 followers

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PHPoC - Scratch Programming 102

PHPoC - Scratch Programming 102

Things used in this project

Hardware components

Software apps and online services

Story

I. Demo

II. Connect Scratch with PHPoC:

III. Scratch programming tutorial:

IV. Source Code

Code

task0.php

Credits

Homer

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