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Thursday, 07 June 2018 06:06

自己作的几首曲子

写了几首曲子,都是使用C大调和弦。借用Dopamine Set里的风格,用KORG PA600来演示。

I need a server which is able to setup the Mosquitto MQTT Broker, this server have to be handle MQTT connections with clients and capable to save MQTT data (payload) into database.

The server also act as a File Server and Web Server where I can upload photos via HTTP Post.

After reading some posts and research, it looks like the Synology NAS having all the features for me to setup the said server. Therefore I decided to choose the Synology DS216j NAS for this project.

Sketch below shows how to split comma or any other character delimited string into an array.

Here is the output

Word 1 : One_1
Word 2 : Two_2
Word 3 : Theree_3
Word 4 : Four_4
--------------------
Word 1 : 1_One
Word 2 : 2_Two
Word 3 : 3_Theree
Word 4 : 4_Four
Word 5 : 5_Five
--------------------
Word 1 : One
Word 2 : Two
Word 3 : Theree
Word 4 : Four
Word 5 : Five
--------------------

This is my experience about how to create webpages & setup my personal website using the CMS (Content Management System) software. My website is 4 years old now, during this time, I learn how to upgrade my website, improve the webpages loading speed, remove virus/malware from website, and a lot more.....SEO, Google Analytic, Google Adsense, Google Captcha, Google PageSpeed Insights, Google Search Console. 

Saturday, 20 August 2016 17:49

Makeblock 3-in-1 mBot Ranger Robot Kit

Makeblock 3 in 1 mBot Ranger Robot Kit is a three-in-one STEM (Science, Technology, Engineering & Mathematics) Educational robot kit which offers the ability to create a Robot Tank, Three-Wheeled Racing Car and a Self-Balance Car. You can program and control the mBot Ranger via iPad, tablets or laptop.

I get my mBot Ranger Robot Kit from GearBest, the price of the kit is $134.87.

This is an Arduino based digital Clock to display real time on a 32x16 LED matrix panel using a DS1307 RTC module. The date and time can be set via serial interface or push button switches.

Wednesday, 20 April 2016 23:41

Arduino based LCD Digital Clock

This is an Arduino based digital Clock to display real time on a 16x2 LCD using a DS1307RTC module. The date and time can be set via serial interface or push button switches.

This is a solution on how to fix the problem where my Seeedstudio RePhone Mass Storage Mode is not working probably.

Mass Storage Mode works in first time, subsequently it does not appear as a "Removable Disk" (Red LED ON, Green LED OFF). I do get Alcatel single RNDIS network interface under the device manager, the RNDIS interface is keep on rebooting every few seconds. This problem only happen on Win7, WinXP is working fine.

You can fix the problem by disable the "automatic driver installation"

Disable automatic driver installation

There's a few ways to disable the "automatic driver installation"

Scan for hardware changes

  • Open "Device Manager" and navigate to "Network adapters"
  • Right click on "Alcatel single RNDIS Interface" and select uninstall
  • Click on Action Menu on the Device Manager and select "scan for new hardware changes"

I'm not a Smartphone addict, I never interested in the features of Smartphone or which Smartphone is best for me. However, as a DIY enthusiast, the Seeedstudio RePhone catches my eye.

The open source hardware manufacturer (SeeedStudio) published the world's first open source, modular Smartphone (RePhone) in Kickstarter on September 23, 2015. RePhone is a GSM +BLE (Bluetooth Low Energy) phone, future version will support 4G LTE. I own a RePhone DIY Kit from Gearbest.

Updated on 23 Mar 2016
Gearbest currently running a flash sale on electrical & tools, you can buy it for cheaper than the creator(Seeedstudio).
http://www.gearbest.com/promotion-electrical-amp-tools-special-480.html

Tuesday, 29 December 2015 20:44

DIY 8x8x8 RGB LED cube

DIY 8x8x8 RGB LED cube

Thank you my friend Siew Goh Chuang, he made this beautiful LED cube:  This is a 8x8x8 RGB LED cube project, a modified version of the LED cube which originally designed by Kavindarrah. This project only modified the hardware but leaving the software (source code) intact. All the source code is available in Kavindarrah's website.

ESP 07 Arduino IDE
The ESP-07/ESP-12 is a generic ESP8266 module which have no bootstapping resistors on board, insufficient decoupling capacitors, no reset circuit, and no USB-serial adapter. This is an article shows you how to connect the bootstapping resistor to the ESP-07 module and upload sketches onto the ESP-07/ESP-12 using the familiar Arduino IDE.

Tuesday, 20 October 2015 22:02

OpenWrt: Control LED manually

Control LED manually

Due to the limited GPIO availability on the wireless router, you may want use the router LED pin to provides a few more GPIOs. This describes how to use the LED pin on a wireless router as binary outputs. 

Tuesday, 29 September 2015 17:22

L298N Motor Driver Controller Board

L298N Motor Driver Controller Board

A guide on how to use the L298N Motor Driver Controller Board, this is a dual motor controller board that allow you to control the direction & speed of two DC motors or one stepper motor.

The L298N Motor Driver Controller Board is a very low cost module, there are several design variants available on the market, mine get from GEARBEST.

2 wheel motor library for Lua running on wireless route

This is a motor library for Lua running on wireless router which flashed with OpenWrt firmware. It allows a wireless router control the motors without using micro-controller. This library works on any dual-full-bridge driver such as L298.

Each motor require two GPIOs for controlling, therefore 2 motors will use up 4 GPIOs. Most of the wireless router may not have enough GPIO to control the motors, but you can use other pin on the router such as the LED pin, this require to unload the leds_gpio module.

Sunday, 20 September 2015 22:15

Compiling OpenWrt from source

Compiling OpenWrt from source

To compile OpenWrt from source, you need a computer running Linux such as Ubuntu. If you are like me and don't have a Linux computer, you can still use your Windows computer to compile OpenWrt.

In order to run Linux on a Windows, you must install virtual machine on you computer. Virtual machines allow you to run any operating system in a window on your desktop, I'm using the free VirtualBox for my case, please read here for details.

Wednesday, 16 September 2015 21:37

Running Ubuntu On Windows

Running Ubuntu On Windows

I'm a Windows user and I always play with Linux on embedded system. Therefore I need a computer which is effective exchange of information between Windows OS & Linux OS.

This article provides information on how to install Ubuntu on Oracle VirtualBox with the following features:

  1. Run both Linux(Ubuntu) and Windows together.
  2. Sharing clipboard content between OS
  3. File sharing between OS
  4. Internet connection sharing

Lua ShiftOut A 74HC595 Shift Register Library for Lua

I want to built a wifi car without using micro contoller, due to the limited GPIO availability on the wireless router, a 74HC595 Shift Register is needed to expand its outputs.

This is a 74HC595 Shift Register library for Lua running on wireless router flashed with OpenWRT, it may run in any linux-based embedded system. It can be used to shift out data from either the most (i.e. the leftmost) or least (rightmost) significant bit.

GPIO Read Write Functions for Lua

This is a very simple GPIO read/write functions for Lua running on linux-based embedded system, it is based on Arduino digital input/output syntax.

Only four functions are available: pinMode, digitalWrite, digitalRead & delay

Update: Added pin_direction_status() function on 16 Oct 2015

Setting up 3G network on Openwrt Barrier Breaker

opkg update
opkg install comgt kmod-usb-serial kmod-usb-serial-option kmod-usb-serial-wwan usb-modeswitch
opkg install luci-proto-3g #optional, this is for 3G device configuration support in Luci
/etc/init.d/usbmode enable

Insert 3G dongle and restart router.

Append to following line to /etc/config/network configuration file. Here is the settings for setup Maxis 3G network.

config interface 'wan'
option proto '3g'
option apn 'unet'
option username 'maxis'
option password 'wap'
option device '/dev/ttyUSB0'
option service 'utms'

Restart the router.

Ubidots real time data monitoring

In my projects I needed a tool to monitor data in real time, the data is captured by a microcontroller and uploaded to the web using a wireless router. Initially I was trying to use yeelink since it is in chinese langguage and yet I'm a Malaysian Chinese.

One month ago, I have tried with Ubidots, there were a few things that caught my eye.

Sunday, 17 May 2015 10:53

BASH Dropbox Uploader on OpenWRT

BASH Dropbox uploader on OpenWRT

This guide is to provide detailed information on how install BASH Dropbox Uploader to a wireless router flashed with OpenWRT. Dropbox Uploader is a BASH script written by Andred Fabriz that allows you to upload, download, delete files (and more) from Dropbox.

Monday, 04 May 2015 20:00

Recover bricked TL-MR3020

If your TL-MR3020 router is bricked with the following symptoms, most likely you can use this method to recover it.

  1. Ping the router without problem
  2. Telnet connection failed
  3. SSH connection failed

 

Solution:

  1. Put the router switch to AP mode
  2. Turn on the router power
  3. Push and hold the "WPS" button
  4. When the WPS Led flash slowly, switch on AP mode to 3G mode. The LED should flash quicky.

Now, you can Telnet to router

 

Erase the root data

Login to the router via telnet and enter the following command. Most likely your router is now recovered. 

mtd -r erase rootfs_data

Continue following procedures if it is still not working.

 

Copy firmware to router

  • Login to router via telnet and change the password in order to enable SSH
passwd
  • Copy the OpenWRT firmware to the router /tmp folder. I personally like and use WinSCP.

 

Upload the firmware to router

SSH to router and write the firmware to router. Where code.bin is your OpenWRT firmware file. 

mtd -r write code.bin firmware

Reboot the router and your router should be working now. If all the above methods is not working for you, then you should go for Serial Console method to recover the bricked router.

How to increase storage on TP Link TL MR3020 with

The TP-Link TL-MR3020 N150 3G/4G Travel Router is a very small device with a size of 74mm x 67mm x 22mm, it has only 4MB flash and 32MB memory. The router have about 428KB (67%) space available after installing OpenWRT Barrier Breaker 14.07, you may encounter shortage of storage when installing certain extensions due to limited of router space. 

By employing OpenWrt's extroot, you can expand the storage capacity of your root file system using the additional space of an added storage device.

Thursday, 05 March 2015 23:29

Arduino based Electronic Queuing System

Queue calling system

This is a Queuing System project requested by a clinic asistant which allows the doctor enter number from a keyboard and display it on a 32x16 LED panel.

This project uses two Arduino, the first Arduino functioned as a SENDER which included a PS2 keyboard and a mini LCD for number input. While the other Arduino is functioned as a RECEIVER which will trigger a "ding-dong" tone and display number on the 32x16 LED panel.

The SENDER uses a PS2 keyboard instead of USB keyboard, USB keyboard will cost higher since it require a USB host shield. You should get a Matrix keypad (please use google translate) in case the PS2 keyboard is not available in the market.

These two Arduino (SENDER & RECEIVER) is connected via a CAT5e network cable, the CAT5e cable provide power to the RECEIVER and also transfer data between two Arduino.

This project provides step by step approach to driving a Dot Matrix Display (DMD) Panel with an Arduino. The DMD is a 512 pixels single colour LED display arranged in 32x16 layout, a 16 pin (2x8) IDC connector is used to interface with Arduino.

In order to drive the 32x16 Dot Matrix Display Panel from Arduino, the DMD library for Arduino is required. You can download it from Freetronics GitHub.

The Freetronics DMD library is able to write letter and text on the display board with limited function, variable string and text centering is not supported. Yeah! now you can use my code to write variable string on the display board and centering it horizontally.

Updated: DMD2 library is released, this library is currently in BETA release.

Sunday, 08 February 2015 21:09

Arduino电子排队叫号机

这是为谋诊所设计的排队叫号机,计数器只需显示两位数。此叫号机使用了两片Arduino,一个安置在房内用来输入编号,称之为发送器,另一个则安装在房外,用来显示编号,称之为接收器。发送器是通过串口发送信息给接收器。

发送器连接了一个PS2键盘来完成输入,当然也可以使用USB键盘,不过必须添加一个USB Host Shield,这样将会增加成本。如果没办法取得PS2键盘,建议使用矩阵键盘。发送器也应用了一个小型LCD,用于显示编号,当然还能显示更多的相关资料。

接收器用了一片32x16像素的矩阵LED单元板,用来显示从串口取得的相关数据。接收器也安装了一个“铃铛”报知器,每当接收到来自发送器的数据,都会温馨提醒一下。

Sunday, 12 October 2014 15:12

Using HEF4094 Shift Registers with Arduino

I have many seven segment modules in my hand. Each module consists of 5 digits and each digit is controlling by individual HEF4094 shift register. As shown in figure above is the seven segment module.

HEF4094 is an 8-stage serial shift register. Data is shifted on the LOW-to-HIGH transitions of the CP (Clock) input. The product data sheet is available here.

HEF4094 operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS (usually ground). There is also 74HC4094 available which operates at 2V to 6V.

I own a TP-Link TL-WR1043 V2.1 wireless router, I would like to test if it is able to run on OpenWRT or DD-WRT. it is first tested on OpenWRT, DD-WRT later, so far it has been working flawlessly for me.

 

About TP-Link TL-WR1043 V2.1 Wireless Router
TP-Link TL-WR1043 V2.1 is a 300Mbps Wireless N Gigabit Router, it has more memory (64MB) compared with the TL-WR1043 V1.x. Here is the comparison:

HW Version

CPU

Ram

Flash

Network

Gigabit

USB

Serial

JTag

1.x

Atheros  [email protected]

32MB

8MB

4x1

Yes

Yes

Yes

Yes

2.x

Atheros[email protected] 64MB

64MB

8MB

4x1

Yes

Yes

Yes

No

此教程使用一个TP-Link TL-MR3020 3G/4G无线路由器来打造简单的无线广告机。目标是提供一个免费热点(hostpot)让公众无线上纲同时弹出hostpot提供者的广告(称之为Splash page 或者Landing page)。

TP-Link TL-MR3020的厂家固件(Firmware)功能有限,不能安装第三方软件包,因此,固件必须升级至OpenWRT,然后再安装NoDogSplash

虽然这里是使用TP-Link TL-MR3020为教题,一般支持OpenWRT的路由器也是适合的。 

This is a guide on how to setting up a simple wireless hotspot using a TP-Link TL-MR3020 3G/4G Wireless N Router installaing with NoDogSplash. The goal is to provide a free hotspot with a splash page to advertise who is providing the hotspot, it should work as well for other OpenWRT supported router.
Friday, 04 July 2014 13:54

Arduino based RGB Matrix LED tester

Arduino based RGB Matrix LED tester

This is a very simple Arduino project which control the 16x32 RGB LED Matrix Panel via an 16pin IDC cable. The Arduino will continuously sending 5 set colours (Red, Green, Blue, White, Black)  to the LED Matrix Panel that allow the technician to find out which part of the LED Matrix Panel is malfunction.

Wednesday, 18 June 2014 23:34

Removing Applications from Raspberry Pi

You might want to remove some applications to free up some space on SD card. Use the following syntax to uninstall a program
sudo apt-get –purge remove APPNAME #replace APPNAME with the name of the app you want to remove
An example to remove Scratch program 
sudo apt-get remove scratch
Tuesday, 10 June 2014 14:52

Raspberry Pi Digital Signage

Raspberry Pi (Model B) is a single-board computer that uses an ARM 11 (ARM1176JZF-S core) processor running at 700MHz (it can overclock up to 1GHz) with 512MB RAM.
 
This article shows you how to turn your Raspberry Pi into a cheap, browser based digital signage solution. It covers setting up a mini webserver on using the lighttpd+PHP web server and also how to start a web browser without a desktop environment.
 
I will use Midori as the web browser since it is a default browser that is found in Raspbian (a free operating system based on Debian optimized for the Raspberry Pi).
Edit the crontab file
sudo su - #switch to supuer user
crontab -e #edit crontab file

Put this line at the end of the file. This will turn off display at 5.30PM and turn on display at 8.30AM

30 17 * * * tvservice -o

30 8 * * * tvservice -p; fbset -depth 8; fbset -depth 16

 
Crontab syntax:
*     *     *   *    *        command to be executed
-     -     -   -    -
|     |     |   |    |
|     |     |   |    +----- day of week (0-6) (Sunday=0)
|     |     |   +------- month (1-12)
|     |     +--------- day of month (1-31)
|     +----------- hour (0-23)
+------------- minute (0-59)
Wednesday, 21 May 2014 12:46

Raspberry Pi Schedule Reboot

Edit the crontab file
sudo su - #switch to supuer user
crontab -e #edit crontab file

Put this line at the end of the file. This will reboot the Raspberry Pi at 1.30PM every day.
30 13 * * * sudo reboot
 
Crontab syntax:
*     *     *   *    *        command to be executed
-     -     -   -    -
|     |     |   |    |
|     |     |   |    +----- day of week (0-6) (Sunday=0)
|     |     |   +------- month (1-12)
|     |     +--------- day of month (1-31)
|     +----------- hour (0-23)
+------------- minute (0-59)
Example Configuration
  • Raspberry IP: 192.168.0.123
  • Router IP (Gateway): 192.168.0.254
  • Subnet Mask: 255.255.255.0
  
List the network interface we currently have available:
cat /etc/network/interfaces
The output should look like this:
auto lo
iface lo inet loopback
iface eth0 inet dhcp
allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
The line iface eth0 inet dhcp shows that it is currently getting out IP address via DHCP. We need to change this line to iface eth0 inet static.

Edit /etc/network/interfaces
sudo nano /etc/network/interfaces
Change  iface eth0 inet dhcp to iface eth0 inet static and add the following settings just below it:
address 192.168.0.123
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.254
Here is an example:

auto lo

iface lo inet loopback
iface eth0 inet static
address 192.168.0.123
netmask 255.255.255.0
network 192.168.0.0
broadcast 192.168.0.255
gateway 192.168.0.254

allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp

Finally, reboot the Raspberry Pi.
 
 
Fixing DNS problems
DNS is the service that converts the website URL, i.e. www.goggle.com into the IP address (173.194.126.36) that is needed for actual communication. 
 
Check your DNS entrie
cat /etc/resolv.conf
 
Here is an example of the output
nameserver 192.168.0.254
The nameserver should same as your gateway (your modem IP). If the nameserver and the gateway is different, you should modify the /etc/resolv.conf file and change the nameserver to your gateway IP.
sudo nano  /etc/resolv.conf
 
 
View the current display configuration
tvservice -s
 
View the /boot/config.txt settings
vcgencmd get_config int
 
Get the list of what is supported by your monitor:
tvservice -d dataFile #dump information to dataFile
edidparser dataFile #load dataFile & display on screen

Midori is a lightweight browser using the WebKit rendering engine and it is a default browser that is found in Raspbian. This is a quick quide to start the Midori browser from the command line without a desktop manager.

 
To start the Midori in full screen mode, use the following command:
xinit /usr/bin/midori -e Fullscreen -a http://domain/homepage.html
 
However it is not in full screen mode, it just fill up about quarter size of the screen. To fix this problem, Midori must run on a windows manager. Here is the solution:
Sunday, 04 May 2014 20:43

Setup a Raspberry Pi PHP web server

Lighttpd is a lightweight web server, with all the essential functions of a web server, PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language. This is a quide on how to install Lighttpd and PHP on a Raspberry Pi.
 
Prerequisite
Sunday, 04 May 2014 11:02

Some useful javascript

Some useful javascript
Create an XML HTTP Request (XHR) object
  1. function create_XMLHttpRequest() { //create new XHR object
  2. if (window.XMLHttpRequest)
  3. {// code for IE7+, Firefox, Chrome, Opera, Safari
  4. xmlhttp=new XMLHttpRequest();
  5. } else {// code for IE6, IE5
  6. xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  7. }
  8. return xmlhttp;
  9. }
 
 
Send request to Server and receive response from server
  • Get replay from php web server: serverResponseInfo=httpGetRequest("http://domain/myReply.php")
  • Read content from a text file: serverResponseInfo=httpGetRequest("myTextFile.txt")
  • Read content from a text file: document.getElementById("myDiv").innerHTML=loadXMLDoc("myTextFile.txt");
function httpGetRequest(url)
{
   xmlhttp= create_XMLHttpRequest();
   xmlhttp.open("GET",url,false);
   xmlhttp.send();
   return xmlhttp.responseText;
}
 
 
Check if file exist
  • To check a file if exist in www root directory: fileExists("/settings.xml")
  • To check a file if exist in the current directory: fileExists("settings.xml")
  1. function fileExists(filename) {
  2. xmlhttp= create_XMLHttpRequest(); //create new XHR object
  3. if(!xmlhttp) return false;
  4. try
  5. {
  6. xmlhttp.open("HEAD", filename, false);
  7. xmlhttp.send(null);
  8. return (xmlhttp.status==200) ? true : false;
  9. }
  10. catch(er)
  11. {
  12. return false;
  13. }
  14. }
 
 
Load an XML file using XML HTTP Request
Eg. loadXML("settings.xml")
  1. function loadXML(XML_filename) {
  2. xmlhttp= create_XMLHttpRequest();
  3. xmlhttp.open("GET",XML_filename ,false);
  4. xmlhttp.send();
  5. return xmlhttp.responseXML;
  6. }
 
 
Convert XML to string
  1. function xmlToString(xmlDoc){
  2. if(xmlDoc.xml){
  3. // MSIE
  4. xmlString = xmlDoc.xml;
  5. }else{
  6. xmlString = (new XMLSerializer).serializeToString(xmlDoc);
  7. }
  8. return xmlString;
  9. }
 
 
Create a string based on date
Example of output: 2014_0502
  1. function createString_accordingDate() {
  2. var today = new Date();
  3. var dd = today.getDate();
  4. var mm = today.getMonth()+1;//January is 0!
  5. var yyyy = today.getFullYear();
  6. if(dd<10){dd='0'+dd} ;
  7. if(mm<10){mm='0'+mm};
  8. return (yyyy + "_" + mm + dd);
  9. }
.
Saturday, 15 February 2014 20:38

Wireless Router Remote Control Car

This is my first RC car control by an Arduino and a wirless router running OpenWRT. There are many OpenWRT supported routers, I'm using a TP-Link TL-MR3020 3G/4G Wireless N Router for this project since it is very slim, low power consumption and it is cheap.

 

RC car features

  • A webcam, the car can be driven without line of sight
  • A horn so that you can honk at people.
  • LED Headlights attached to the front of the car
  • Two wheel drive motor
  • Windows GUI application or web interface
  • Future Additions: Control by a smartphone (Android & IOS)
 
TPicShow is an image slider VCL that enables you to create amazing splash screens and 176 transitional effects in pure Delphi code.
 
Features:
  1. Image transition can be controlled programmatically
  2. Image can be stretched or centered in the client area of the control
  3. Control can show a background image as centered, stretched, or tiled
  4. Transition process can use a separate thread
  5. New transitional effects can be easily implemented and added.
 
TPicShow's last update is on July 19, 2010 which does not support RAD Studio XE. By creating a package file, you can installing and running TPicShow on RAD Studio XE5 without any problem.
 
Count number of digits in a number(integer). Eg. countDigits(5678) return 4
  1. byte countDigits(int num){
  2. byte count=0;
  3. while(num){
  4. num=num/10;
  5. count++;
  6. }
  7. return count;
  8. }
 
 
Extract a digit from an number(integer). Eg. getDigit(5678,2) return 6
  1. int getDigit(unsigned int number, int digit) {
  2. for (int i=0; i<digit-1; i++) {
  3. number /= 10;
  4. }
  5. return number % 10;
  6. }
 
 
Extract all digits from a number and store them to an array
  1. #define MAX_NUMBER_OF_DIGITS 5
  2. byte array_to_hold_digit[MAX_NUMBER_OF_DIGITS];
  3.  
  4. void setup(void) {
  5. Serial.begin(9600);
  6. extractDigit_Save2Arrary(5678);
  7. Serial.println(array_to_hold_digit[0]);
  8. Serial.println(array_to_hold_digit[1]);
  9. Serial.println(array_to_hold_digit[2]);
  10. Serial.println(array_to_hold_digit[3]);
  11. }
  12.  
  13. void loop(void) {
  14.  
  15. }
  16.  
  17. /*----------------------------------------------------------------------------
  18.  count number of digits in a number(integer)
  19. ----------------------------------------------------------------------------*/
  20. void extractDigit_Save2Arrary(int number){
  21. byte number_of_digit = countDigits(number);
  22. for (byte i=0; i<number_of_digit; i++) {
  23. array_to_hold_digit[i] = getDigit(number,number_of_digit-i); //store each digit to array
  24. }
  25.  
  26. /*
  27.   for (byte i=0; i<number_of_digit; i++) {
  28.   Serial.print(array_to_hold_digit[i]);
  29.   }
  30.   Serial.println();
  31.   */
  32. }
  33.  
  34. /*----------------------------------------------------------------------------
  35.  count number of digits in a number(integer)
  36. ----------------------------------------------------------------------------*/
  37. byte countDigits(int number){
  38. byte count=0;
  39. while(number){
  40. number=number/10;
  41. count++;
  42. }
  43. return count;
  44. }
  45.  
  46. /*----------------------------------------------------------------------------
  47.  extract a digit from an number(integer)
  48. ----------------------------------------------------------------------------*/
  49. byte getDigit(unsigned int number, int digit) {
  50. for (int i=0; i<digit-1; i++) {
  51. number /= 10;
  52. }
  53. return number % 10;
  54. }
 
 
Saturday, 21 December 2013 22:21

Debouncing Multiple Switches

If you want to input a manual switch signal into a digital circuit you'll need to debounce the signal so a single press doesn't appear like multiple presses. 
 
There is a Bounce library for Arduino which is very easy to use. However there is limitations with this Bounce library.
  • You are unlikely to enable the internal pull-up resistor on switch pins, therefore each switch require an external pull-up resistor
  • It is not possible to detect the switch state before main loop (setup). When you press a switch during power on, you will never get the state of the switch.
Tuesday, 17 December 2013 21:51

Arduino function with optional argument(s)

Function Declaration and Function Prototypes: function prototype allowing the function to be used before it is defined.
functionReturnType myFunctionName(optionalArgumentType optionalArgument = defaultValue);
 
Function Implementation

functionReturnType myFunctionName(optionalArgumentType optionalArgument);
{
   // put your code here
}

 
Function calls

myFunctionName(); // Use the default value
myFunctionName(1); // Use specific value

 
Example
  1. int myFunction(int optionalArgument = 1);
  2.  
  3. void setup() {
  4. Serial.begin(9600);
  5. }
  6.  
  7. void loop() {
  8. Serial.println(myFunction()); // Use the default value
  9. Serial.println(myFunction(2)); // Use specific value
  10. }
  11.  
  12. int myFunction(int optionalArgument)
  13. {
  14. return optionalArgument;
  15. }
 
The breadboard.zip hardware configuration archieve is not working on Arduino software version 1.0 and above
 
Here is my boards.txt setup for ATMega328 which is working on version 1.0 and above
Modify the file ...\your_arduino_folder\hardware\arduino\boards.txt by adding these few lines:

##############################################################
atmega328bb.name=ATmega328 Optiboot (8MHz internal clock)
atmega328bb.upload.protocol=arduino
atmega328bb.upload.maximum_size=30720
atmega328bb.upload.speed=57600
atmega328bb.bootloader.low_fuses=0xE2
atmega328bb.bootloader.high_fuses=0xDA
atmega328bb.bootloader.extended_fuses=0x05
atmega328bb.bootloader.path=arduino:optiboot
atmega328bb.bootloader.file=optiboot_atmega328.hex
atmega328bb.bootloader.unlock_bits=0x3F
atmega328bb.bootloader.lock_bits=0x0F
atmega328bb.build.mcu=atmega328p
atmega328bb.build.f_cpu=8000000L
atmega328bb.build.core=arduino
atmega328bb.build.variant=standard

 
And here is the boards.txt setup for ATMega8

##############################################################
atmega8noxtal.name=ATmega8 Optiboot (8MHz internal clock)
atmega8noxtal.upload.protocol=arduino
atmega8noxtal.upload.maximum_size=7168
atmega8noxtal.upload.speed=38400
atmega8noxtal.bootloader.low_fuses=0xe4
atmega8noxtal.bootloader.high_fuses=0xc4
#atmega8noxtal.bootloader.path=atmega8_noxtal
atmega8noxtal.bootloader.path=optiboot
atmega8noxtal.bootloader.file=optiboot_atmega8.hex
atmega8noxtal.bootloader.unlock_bits=0x3F
atmega8noxtal.bootloader.lock_bits=0x0F
atmega8noxtal.build.mcu=atmega8
atmega8noxtal.build.f_cpu=8000000L
atmega8noxtal.build.core=arduino
atmega8noxtal.build.variant=standard

 
Note: Do not modify the boards.txt in your Arduino sketch folder (eg. ...\My Documents\Arduino\hardware\...boardx.txt), it will not work.
 
 

Using an Arduino board to burn the bootloader
If your ATMega8/ATmega328 already configured to use external clock, then wire up the Arduino board & microcontroller as show in figure 1, otherwise (microcontroller configured to use internal clock) you can follow either figure 1 or figure 2.

Fig. 1 Using an Arduino board to burn the bootloader

 

Fig. 2 Using an Arduino board to burn the bootloader

  • Upload the ArduinoISP sketch onto your Arduino board.
  • From Tools>Board menu, select ATmega328 Optiboot (8MHz internal clock) if you want to burn the bootloader on ATMega328 microcontroller
  • From Tools>Board menu, select ATmega8 Optiboot (8MHz internal clock) if you want to burn the bootloader on ATMega8 microcontroller
  • From Tools>Programmer> menu, select Arduino as ISP
  • Select Burn Bootloader from Tools menu to start burning bootloader to microcontroller
Tuesday, 05 November 2013 20:36

Sharp GP2Y0A21红外线测距传感器

Sharp GP2Y0A21是一颗红外线测距传感器,易于使用,价钱廉宜,且低功耗。 规格如下:
  • 距离测量范围:10至80cm(4“到32”)
  • 工作电压:4.5V至5.5V
  • 输出类型:模拟电压
  • 平均功耗:35mA
  • 峰值功耗:约200mA
  • 允许的最大角度:> 40°
  • 更新频率/周期:25 Hz/40毫秒
Sunday, 03 November 2013 17:49

Sharp GP2Y0A21 IR distance sensors

Sharp GP2Y0A21 is an infra-red distance measuring sensor unit,  it is extremely effective, easy to use, very affordable and has low power consumption. specification as follow:

  • Distance measuring range: 10 to 80cm (4" to 32")
  • Operating voltage: 4.5V to 5.5V
  • Output type: Analog voltage
  • Average power consumption : 35 mA
  • Peak power consumption : about 200 mA
  • Output voltage differential over distance range: 1.9V 
  • Maximum allowable Angle : > 40 °
  • The frequency of updates/cycle : 25 Hz/40 ms
Burning sketches to the Arduino board with an AVRISP MKII programmer without using the bootloader. This allows you to use the full program space (flash) of the chip on the Arduino board. So with an ATmega328, you will get 32KB instead of 30KB of space. It also avoids the bootloader delay when you power or reset your board.
Tuesday, 22 October 2013 22:13

Identify which Arduino bootloader do I have

Here’s an Arduino sketch which tries to identify the bootloader and reports it on the serial port
 
The sample output look like this:
[bootCheck.2]
  CRC 2048b @ 0x7800 = CD70
  CRC 512b @ 0x7E00 = FD70
Boot loader: OptiBoot 4.4
 

// Detect which type of boot loader is present, using a fixed built-in table
// 2012-03-06 <This email address is being protected from spambots. You need JavaScript enabled to view it.; http://opensource.org/licenses/mit-license.php

#include <avr/pgmspace.h>
#include <util/crc16.h>

#define VERSION "2"

// list of all known boot loaders with their unique signatures
struct { word crc; const char* desc; } signatures[] = {
0x489C, "Duemilanove",
0xF1A0, "Nanode (Duemilanove mod)",
0xFD70, "OptiBoot 4.4",
0, 0
};

static word CalculateChecksum (word addr, word size) {
word crc = ~0;
prog_uint8_t* p = (prog_uint8_t*) addr;
for (word i = 0; i < size; ++i)
crc = _crc16_update(crc, pgm_read_byte(p++));
Serial.print(" CRC ");
Serial.print(size);
Serial.print("b @ 0x");
Serial.print(addr, HEX);
Serial.print(" = ");
Serial.println(crc, HEX);
return crc;
}

static const char* IdentifyBootLoader (word addr, word size) {
word crc = CalculateChecksum(addr, size);
for (byte i = 0; signatures[i].desc != 0; ++i)
if (signatures[i].crc == crc)
return signatures[i].desc;
return 0;
}

void setup () {
Serial.begin(57600);
Serial.println("\n[bootCheck." VERSION "]");

const char* message = IdentifyBootLoader(0x7800, 2048);
if (message == 0)
message = IdentifyBootLoader(0x7E00, 512);
if (message == 0)
message = "(UNKNOWN)";

Serial.print("Boot loader: ");
Serial.println(message);
}

void loop () {}


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