Sending Message to Serial Port of Router using Lua
- PHP require to install lighttpd,lighttpd-mod-cgi,lighttpd-mod-fastcgi,php5-cgi,php5-fastcgi,libsqlite3, installation is complicated & consume resources.
- ser2net/socat is very simple but did not support web service.
- Lua comes as a default in openWrt and support web service. The goodies is OpenWRT using Luci for web GUI and LuCI is an embedded rapid application development framework written in Lua.
- Arduino duemilanove connected to a TP-LINK TL-WR1043ND router which flashed with OpenWRT.
- Using 16 Channel Relay Arduino Controller for the Arduino sketch
First, we must install USB-Serial library for router in order to making the USB port act as a serial port. Here I install FTDI library since Arduino duemilanove using FTDI chip for interface.
| opkg install kmod-usb-serial-ftdi |
Verify USB-Serial port
To make sure the USB-Serial port is working, enter code below. You should see FTDI USB Serial Device converter now attached to ttyUSB0.
| dmesg | grep -i usb |
Execute Lua script from Router
The most simple way to execute Lua script is SSH to router and enter lua. Now you can enter Lua command line by line.
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login as: root
_______ ________ __ |
Open the Port
This is particular important, it use to prevent autoreset on initiation of serial.
| cat /dev/ttyUSB0 |
Arduino should acknowledge and reply message to router. This should look like this
Sending command to USB-Serial
While cat /dev/ttyUSB0 is still running, open another incident and execute script below.
This will open a ttyUSB0 port and send on3 (include carriage return) to the port. Arduino channel 3 should turn on.
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io.output("/dev/ttyUSB0")
io.write("on3\r") |
Completed step should look like this.
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[email protected]:/www# lua
Lua 5.1.4 Copyright (C) 1994-2008 Lua.org, PUC-Rio (double int32) > io.output("/dev/ttyUSB0") > io.write("on3\r") > |
Execute Lua script from a File
Save script below to router /www/test.lua. Do not use notepad to create the file (it is not a unix file format). Here I use WinSCP.
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print("Turn on channel 2 and channel 3") |
Run the file as shown in figure below. Channel 2 and Channel 3 should turn on.
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[email protected]:/www# lua /www/test.lua |
Open USB-Serial port on Reboot
- Login to router
- Click System -> Startup
- Scroll down until you see Local Startup
- Insert cat /dev/ttyUSB0 in front of 'exit 0' as shown in figure below
- Reboot the router
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# Put your custom commands here that should be executed once
# the system init finished. By default this file does nothing. cat /dev/ttyUSB0
exit 0
|
Execute Lua file from Browser
- The Lua file must place in /www/cgi-bin directory of router.
- The first line of the Lua file must start with #!/usr/bin/lua
- Change file permission to 0755 or 0777.
Having the same example test.lua, copy it to /www/cgi-bin and rename it to test (without extension), you should have /www/cgi-bin/test in the router.
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#!/usr/bin/lua
print("Turn on channel 2 and channel 3") io.output("/dev/ttyUSB0") io.write("on2\r") io.write("on3\r") |
Setting File Permission to 0755. This is particular important or else you will not allow to run the file.
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chmod 0755 /www/cgi-bin/test
|
Execute Lua script from Browser
- Open a browser
- Enter http://192.168.1.1/cgi-bin/test (192.168.1.1 is the router IP address, you should use your own IP address)
- Channel 2 and Channel 3 should turn on
Authentication
Use code below for authentication before execute Lua file. The user name & password same as the router login user name & password.
| echo '/cgi-bin:root:$p$root' > /etc/httpd.conf; /etc/init.d/uhttpd restart |
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command="echo yourMessage\r > /dev/ttyUSB0" |
