WOL and Remote Control by PDA
While bench testing my car pc 802.11b to 1xRTT routing setup last weekend I decided to try a theory that has been discussed here on the forum a few times. In previous threads members have ask about using the built in WOL “Wake On LAN” functions of the VIA MB to remotely startup and control the PC in the car. Here is what I found.
The MB I used is a VIA EPIA MII 10000, like most this board has built in 10/100 Ethernet LAN port along with a separate WOL plug to be used with a PCI based Ethernet card. I used the motherboards built in LAN port connected to a Linksys WAP 11 access point and a 1Watt bi-directional signal amplifier [kick *** connection range of over 2 miles] to boost AP coverage. These LAN ports are connected together with a standard RJ45 crossover cable to eliminate the need for a switch or hub in the car. The cars primary outbound full time Internet connection is via PCMCIA Sierra Wireless 1xRtt cellular modem running on Win XP Pro OS.
To use the WOL features you only need to enable it under XP.
>>VIA Rhine II Fast Ethernet Adapter
>>>>>>Allow this device to bring the computer out of standby.
Do not check: “Allow only management stations to bring computer out of standby”. If you enable this option you will need to send a properly formatted packet to the PC’s IP or MAC address to wake up the computer. Without this enabled any type of packet [ping, http, dns, ect] directed to the IP address of the LAN port will be enough to wake up the PC.
Since I am also using this PC as a router, I enabled connection sharing on the wireless dial-up connection. This forces the LAN port to use the [Private] IP address 192.168.0.1 for packet routing. In this mode the LAN port will also do DHCP and assign private IP’s to any machine that connects to the WAP. This old Linksys WAP I used does not require an IP address to work.
The PDA I used for testing was a HP iPAQ with built in 802.11b card, however this should work the same with any device that can connect by Wi-Fi. I simply made sure the PC connection sharing was working properly between the PDA, Wi-Fi and the Dial-Up connections to the Internet. Once I confirmed this worked I put the computer into standby mode, and then sent a simple ping packet to the IP address 192.168.0.1 from the PDA and the PC came out of standby.
Testing further I found this also works the same from Hibernate mode. However one thing I noticed was if I removed the IP or connection settings from the PDA it would not work because DHCP requests will not wake up the PC, you must know the MAC or IP.. To overcome this I suggest giving the PDA a static IP of 192.168.0.2 or something in the same net block the PC’s LAN port. Also set the default gateway IP on the PDA or remote device as 192.168.0.1 so it knows where to route the Internet bound packets.
Using static IP’s on both devices I was able to just open a web browser on the PDA and request a web page, the PC starts up and dials the default connection, and after a few seconds routes the traffic to the PDA as normal. To shut down the PC there is many choices of remote control software for PDA’s and PC’s. For now I just set the power management features to standby after 20 minutes and Hibernate after 1 hour. Once I get it all back in the car I will try out some of the software options like MS Terminal Server to remote control Frodoplayer and other apps.
The only down sides I have found so far are the WAP must be powered by 5V [converter required] and the Wi-Fi Amp [optional] by 12V all the time in the car for this to work. Though both are minimum power consumers when idle you will need to monitor for drain over extended periods parked. If anyone knows of a cheap automatic cut off solution based on voltage like in the ITPS, please let me know.
Also I would probably enable WEP and MAC filtering on the WAP to keep the script kiddies out of the car PC and off the cell connection. Besides that I can’t wait to test the range on this in the real world. Previously I had tested this same equipment at over 2 miles with no LOS “Line Of Site” against a laptop, the PDA’s might do about ˝ that if lucky.
The remote management / control possibilities are endless; streaming audio video from the car to PDA or laptop is the first I plan to setup. Hope this inspires some of you to expand on this idea, I’ll post more pics once I complete in car the install.