Mini web server takes control into the home

Tom Shelley reports on a development that could point the way to home automation A new 'web controller' is in fact a miniature server with its own programmable e-mail facility to do much more than just send simple alarm messages. It sits easily in the palm of the hand and is sufficiently low cost to be of interest to constructors of building alarm and security systems, pointing the way to future products likely to be found in the home. The Hitachi EH-WD10DR web controller is much more than a web-enabled PLC, while costing significantly less at a list price of only £550. Its SMTP (Simple Mail Transfer Protocol) capabilities allow it to send emails in response to up to 16 different triggers. Each message can be sent to up to eight addresses, with up to 64 characters in the subject line, up to 256 characters in the message body, and up to 3 data words delivering quantities of interest, which might be temperature, power consumption or the number of cars that have entered a car park. The device has built-in HTTPD (Hyper Text Transfer Protocol Daemon) capabilities that allow it to be programmed remotely through any standard browser running on a PC. Unlike a conventional server, its programming is stored in Flash memory and cannot be modified, so it is impervious to viruses. It can be connected directly to the Internet, protected only by its password, although if the application is critical, UK vendors Silverteam suggest that it is probably best employed with connection to a LAN with remote access via a VPN connection with its own additional security. It can communicate via an Ethernet and an RS232C port as well as having 6 24VDC inputs and 4 relay outputs. In a demonstration organised by Silverteam, a unit attached to a simulated conveyor in Great Yarmouth, Norfolk was being addressed from a laptop PC browser in Essex attached to a standard dial up telephone connection. The system was also being observed remotely by webcam. The conveyor in Norfolk could be turned on and off in Essex and web pages interrogated and messages emailed back about system status and how many boxes had been 'made' while webcam images showed that what was being reported was in fact the case. Web pages stored in the controller are limited by a present maximum capacity of 16 file cases of 4 kbyte each although file cases can be combined to store graphics if required. Typical intended applications include security, working with a camera and sensor. When the sensor detects an intruder, it can instruct the camera to capture a picture and report the event to the system administrator. It can also be used to monitor the status of point of sale activities in retail outlets while allowing the monitoring and control of refrigerators and heating systems. Silverteam staff also predict applications in home automation, especially with regard to security. It should be remembered that the value or some homes and most boats in Norfolk makes the cost of the web controller look quite trivial. Silverteam email Silverteam Pointers * Controller can store browser accessible web pages about detected events and measured quantities as well as send emails. * Emails can be sent in response to up to 16 trigger events to up to 8 addresses each with up to three data words of information about quantities being measured * The device can be programmed remotely by any PC based web browser