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Wednesday, 25 September 2013 18:40

Using 74HC595 Shift Registers with Arduino

The 74HC595 is a very handy IC used in many microcontroller projects, it is a 8-bit serial-in, serial/parallel-out shift register with output latches.
 
Data is shifted on the positive-going transitions of the shift register clock input (SHCP). The data in each register is transferred to the storage register on a positive-going transition of the storage register clock input (STCP).
 
The shift register has a serial input (DS) and a serial standard output (Q7S) for cascading. Data in the storage register appears at the output whenever the output enable input (OE) is LOW.
 
This is incredibly helpful if you need more digital outputs then the 14+6 that the ATmega328 on the Arduino Uno provides, with only 3 data pins, you can control an almost unlimited amount of outputs.
 
Upon completion of this tutorial, you should be able to controlling the 74HC595 as below:
  • Using 74HC595 Shift Registers with Arduino
  • Daisy chaining 74HC595 shift registers
  • Different ways (binary, decimal, hex) to hold the data using an array
  • Using bitshift, bitwrite operators
  • Direct port access for faster manipulation of the IO pins 
Aarduino communicate with Vixen
Vixen is a free and popular light show creator software. With a PC and some hardware, anyone can have a professional-looking lighting display synchronized to music.
 
The latest version is Vixen3, the most attractive feature is supported for preview. Compare to Vixen2, Vixen3 is a bit difficult to use & lack of some features in Vixen2. Please correct me if I'm wrong.
 
This tutorial is based on Vixen2, please download Vixen2 and install it to your computer. Prior to Vixen2, you must have install Microsot.NET Framework 2.0 in your computer.
Explains how to bridge network using two wireless routers, the first (Host) router is configure as Access Point & the second router (TL-MR3020) is configure as Client mode. Same method should apply to all other OpenWRT routers as well.
 
Prerequisites
  • Host router configure as Access Point. If you already setup a wireless internet connection in your house, usually your modem is configured as Access Point mode.
  • A working OpenWRT on TP-LINK TL-MR3020 Portable 3G/4G Wireless N Router
 
The routers is configure as two different subnet, assume using settings below as the example.
  • Host router IP: 192.168.1.1
  • Host router subnet mask: 255.255.255.0 or 255.255.0.0 if you want to access 192.168.0.x from 192.168.1.x
  • Host router SSID: ABC
  • Client router IP: 192.168.0.1
  • Client router subnet mask: 255.255.255.0
Sunday, 07 July 2013 15:40

TP-LINK TL-MR3020 + OPENWRT + WEBCAM

This project uses an inexpensive TP-LINK TL-MR3020 Portable 3G/4G Wireless N Router with an Linux UVC supported camera to create an IP Camera that can be placed in a good location for surveillance.
 

Prerequisites

 
After flashing the latest OpenWRT image file (openwrt-ar71xx-generic-tl-mr3020-v1-squashfs-factory dated 03-Jun-2013), my TL-MR3020 is bricked. All the LED is keep on blinking (about 3 seconds once) except power LED, and the network is getting connected and disconnected every 3 seconds. Very lucky that the problem was fiexed by using serial console and Tftpd32 method.