Using low cost hardware available from retail vendors, a wireless sensor network can be constructed using WIFI. In a earlier article here at Home Toys “Adding some simple monitoring tools, and Internet ready devices, your existing network connection brings your real world to your wired world”, we described using simple print servers to create a sensor. In this article we will extend the same concept to create a wireless sensor system. We will be building upon the SNMP (simple network management protocol) supported by a number of low cost print servers both wireless and wired available from a number of retail network hardware vendors. These devices send a short status message to a specified IP address, it does not have to be accessible from outside your network, no open ports, with simple web based setup!

By combining, low cost SNMP enabled wireless print servers and a web browser you can create an easy to implement wireless sensor network. Wireless print servers like the DP-311P from D-Link combine both the web page interface that we used in our previous articles, with an added ability to send SNMP alert messages. These messages are sent when the device changes state from online to offline, and also sent when going from online to out of paper. Very limited true, but one DP-311P can be configured to watch for two major events in your home or office, HEAT and WATER! Going back and looking at ?Adding some simple monitoring tools, and Internet ready devices, your existing network connection brings your real world to your wired world?, we described some easy to assemble sensors for both water and temperature. The Temperature sensor can be constructed completely from components available at any home supply center. The water sensor requires a float switch that can be obtained from an electronics supply site.

Water Sensor


Door and Window Switches

Using one or more SNMP enabled print servers we can construct a network of sensors connected both wireless with WIFI and wired. Once we have a sensor network the next problem is of course to do something with the information, SNMP is well established in the networking world, a great source for information and resources can be found at Bringing us to the service offers. We have added support for receiving SNMP alerts from print servers from a number of vendors (,, and more). This service work much like what we have described in our previous articles here at Home toys, this is perhaps the simplest of all!

Set your printer server’s SNMP settings following the instruction from the web site as you configure the alert messaging options. The last message received from your device is viewable on allowing for easy testing of your configuration. Only the short SNMP message is sent from your printer server to’s SNMP server.

We at have been working on creating a simple to use, lowest cost, home/office networked monitoring and control solution. If you refer back to the other articles we have written here at – February – 2005 – December – 2004 – October – 2004 – August – 2004 – June ? 2004

In concept we have tried to present simple interfaces and simple hardware requirements, in essence a thin client approach. Web based services to support the notification systems, and simple local clients, some software, some hardware. All as simple and low cost as possible. The new SNMP service from extends this concept allowing for the creation of wireless sensor and control networks with readily available low cost retail equipment. More details can be found at