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Active RFID, USB And WiFi Environmental Monitoring In SMB Server Rooms

Sep 12, 2013

Questioning RFID as a cost effective solution for Small and MidSized Business IT spaces.

Caught again! As I left a big box home improvement store recently, one of my purchased items set off the security system at the exit used to prevent theft. The message wasn’t quite “Halt, you must be frisked and searched to prevent your attempted theft of our merchandise!,” but the feeling was close. Of course anyone who has seen this happen knows that the cashiers are so used to false alarms or alarms because one of them did not deactivate the security tag, so they either call you back and apologize or wave you on. So how effective is this technology?

Passive RFID “tags” have been in use since the 1980s. For the past decade they have become commonplace in many applications including automobile assembly to track progress through production, pharmaceuticals during transport, animal identification and the ubiquitous tags found on merchandise in many national chain stores. This is because passive RFID tags are relatively effective and can now be produced at a cost so low they can be considered disposable. Many are integrated into the printed label and read by entrance and exit portals to buildings, as shown in the images below.

There are two kinds of RFID tags, active and passive. The images above are for a passive device.  The RFID device is activated by electromagnetic induction from the RFID portal, like the ones seen at big box retail stores. Their range is meter or so, thus every door has its own portal. And while environmental monitoring sensors can be built into these devices, the most common environmental applications use active RFID tags. These battery powered sensors and transmitters can operate over a range of a few meters to 100 meters in some cases, operating in frequencies associated with WiFi.

RFID tools have been in use in transportation, distribution and inventory control systems for many years.  In 2003 Wal-Mart announced they will require passive RFID tags in products from their top 100 suppliers. The initiative received enormous press setting off an avalanche of RFID offerings. The retail sales market peaked in 2007 before a halt, followed by renewed interest in recent years where Wal-Mart uses the devices to help manage in-store inventory more accurately. (Link to Smartplanet Article About Wal-Mart & RFID Market)  These are passive, read-only devices.

In recent years active RFID has been finding its way into data centers, particularly for DCIM products. Suppliers use active RFID technology for wireless asset tags and modify them for use as environmental and power sensors. Active, battery powered RFID devices are used instead of passive devices to increase their range. They take the place of wired, WiFi, Bluetooth, and Zigbee devices. For inventory control and asset utilization the granularity of data is important and RFID may be able to deliver a lower cost per point in multiple tag applications, very useful for large, well-funded data centers.  

For Small and MidSized businesses with smaller server rooms and budgets, RFID may add unnecessary cost, particularly if used primarily as an environmental monitoring device. For example, in a small server room with a handful of IT, server and telecom racks the biggest concern is overheating particularly since these rooms were former storage closets or small, windowless offices. And the most significant reason for overheating is loss of cooling from the facility’s air conditioning, mainly because these spaces often are tied to the building’s main HVAC system and do not have dedicated cooling units.

For such applications, a high level of data granularity is not generally required. A single temperature sensor is often enough to monitor the room’s temperature and send alerts when things begin to get too hot. The added cost of an active RFID sensor tag to the RFID portal/network interface device means more devices to buy and maintain, and a longer payback period. The added burden of monitoring and changing active RFID tag batteries means higher maintenance cost, particularly if the individual responsible for maintaining the IT systems inherited the device without much training as to the maintenance requirements.

Simple, easy to use and install, low-cost USB or WiFi temperature or temperature/humidity devices are often more cost effective for SMB server and telecom rooms. And WiFi devices can often support multiple sensors for very low added cost, making them very well suited for smaller and midsized IT rooms. 

When considering environmental monitoring technology for SMB server rooms, IT professionals will want to compare the performance, cost, maintenance and ease of use of the myriad of devices on the market.  Buying “right sized” technology can help meet the current need and budget, but also ensures the installation is up and running quickly, providing the protection the business needs and a shorter RoI. For information about USB, WiFi, Cellular and Wireless sensors, one can visit Temperature@lert’s website at


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