The components in the kit enable wireless and battery-free operation of the sensor nodes at a distance of 40-45 feet (13-15 meters). Each sensor board can measure temperature, humidity, light, and an external sensor. This can be used for a number of applications including building automation, energy management and industrial monitoring. Power is provided by Powercast’s new 3W transmitter (TX91501-3W-ID), which also sends factory-set data. The P2110 Powerharvester receiver converts the RF energy from the receiving antenna and stores it into a capacitor, which is then boosted to operate the wireless sensor board. The Microchip XLP 16-bit Development Board with the 802.15.4 radio is the access point.

The evaluation boards replace the full-featured Lifetime Power Kit.

Batteries are used in numerous small, portable, and mobile electronic devices. Powercast’s technology enables these devices to use rechargeable batteries and be finally untethered™ from power cords or inconvenient, close proximity charging methods. Disposable batteries and their adverse environmental impact can be eliminated from devices with Powercast’s RF energy harvesting and embedded wireless power solutions.

Powercast’s technology can provide constant charge, over distance, between one or more sources and multiple receivers. These devices can also be dormant, with zero stand-by power, and activated remotely with power being sent on-demand, on a scheduled basis, or continuously.

The Kit is important because it creates an opportunity to discover how this small component provides such a powerful value proposition.  Can RF energy harvesting be used in conjunction with 100’s and even 1,000’s of applciations?  Does power transfer over distance provide an opportunity to do really unique things?  The Kit begins the process, for any designer or engineer, to start answering these questions.

This begins by understanding the Friis equation.  Friis equation really answers one of the fundamental questions that any designer or engineer asks, when considering RF wireless power.

Friis equation illustrates the elegance of RF wireless power and the flexibility of the solution.  By changing Radio Frequencies havested, by changing distances, by changing transmit power (or ambient power available) … the Powerharvester module will produce different electrical power outputs.  Furthermore, by coupling this power with batteries or capacitors, additional enhancements can be designed into the power distribution system.

No wireless power technology has this variability.  If the designer and engineer understand and embrace this variability, then the world is without limits.  However, at the same time, this is the fundamental characteristic of TRUE WIRELESS POWER.  Inductive power is really limited to the high current that can drive a coil.  Piezo is limited by the energy harvested from a mechanic.  Only RF Wireless Power has the elegance of being a “design in” solution.

The Lifetime Power Evaluation and Development Kit “scratches the surface of this self-discovery.  On a personal note, it is really a invitation from Powercast to smart people to figure out the design templates that make sense.  What can you do with 20 mWatts over 30 feet in a wireless sensor network?  What can you do with a wireless relay or switch, capable of harvesting ambient energy?  We are as excited, as we hope you are, in figuring this out.  If we work together, I think we create an entire category of wireless power … true, unique and elegant.

RF Wireless Power is an elegant far field and ambient energy harvesting technology.  Because our world already is saturated with non-ionic RF emissions, this technology has an astounding potential of establishing itself as “wireless power for a wireless world.”  While Powercast remains focused on development and patent investment of our core technology, we are equally invested in enabling a WW users community to start using this technology.  Our corporate attitude is to promote use in a broad and universal way.

This Lifetime Power Kit provides a way for everyone to get involved in this revolution.  To support this, Powercast will be launching in 2009 a series of blogs and forums to promote our evangelists ideas, issues and concerns.  Our dedication to this groundswell promotion is to allow us all to imagine … the future of wireless power.

Wireless Sensor Networks

An IT Manager working in conjuction with the Building Engineer have decided to create an eco-friendly building.  They have proposed to their corporation that by upgrading the HVAC system, the power distribution system, adding eco building materials, and adding alternative energy solutions … that they can save the company substantial money.  They believe that the operational saving for this building can realize a $750,000 savings year over year, and can pay back the additional investment in 4 years.  The presentation was impressive, and managment approved their program.

As someone who has had experience with this very scenario, I can bear witness in the “best intentions” of this kind of arguement and can bear witness in the “breakdown” in the execution of this scenario.  So lets fast forward to 1 year from implementation.

Several suprizes have now occured during the year.  First, the savings projections of the solution were overstated by a factor of x2.  We believe that this is a result of three important real world observations:

• Overstatement of our vendors as to the impact that their product solutions would have, and because we served as the integrator, it is hard to pin down which element is underperforming as advertised.
• The human condition … by this we modeled the solution and saving based upon perfect or expected behavior of people in the building.  However, we discover that they are unpredictable and uncontrollable.  Inhabitants disable the systems (tempurature sensors, automated window blinds, security doors, etc), they open windows, they leave the door open to the outdoor smoking area and so on.
• Understatement of the granularity required to control costs.  The sensor company told us that we needed temperature sensors set up to take a recorded measurement every 1 hour.  The lighting controls were set up on a 90 minute turn off period.  However in both cases, we recognized that by gaining sensor measurements every 10 minutes and shutting lighting down after 30 minutes, we could aggressively recover savings.

Batteries become the achillies heal

With this familiar scenario, the operators soon realize that their increased challenges, both financial and operational, drove them to over-use the systems they put in place.  At that point, they will recognize a significant limitation … primary batteries used.  One Wireless Sensor Manufacture CEO recently was speaking at a Sensor Trade Show, and stated that they expected their sensor batteries to list 1 year.  The audience reacton was almost as if the CEO had told a good joke.

Batteries are the most limiting factor in deployment of wireless sensor networks.

But as the scenario above illustrates, the greater the need or use of the eco-friendly systems, the greater the limitation of primary batteries.  Meaning the more the system is used, the greater the problem.  And in a case of 1,000 nodes using primary batteries, the cost of changing these batteries out every month starts to mount up (batteries, labor, overhead, downtime and disposal).

Lifetime Power in Wireless Sensor Networks

Lifetime Power is a concept where a Powercast Powerharvester Module(tm) is integrated into each node.  That node now has essentially a renewable power source on board.  This Powerharvester can provide power to a rechargeable battery, to a capacitor board, or to an ULP device directly.  Coupling energy harvesting with the power system of the node creates an important realization.

• The operator never has to change batteries out again.
• The node itself remains at peak operation, rather then become inaccurate as battery power dissipates over time.
• System operation is optimized because downtime resulting from battery discharge is eliminated.

This is what Lifetime Power is.  It doesn’t necessarily guarantee that the sensor will always remain powered, because there are always defects, component failure or a use case that is problematic to energy harvesting.  However, Lifetime Power is the promotion of an idea that batteries, capacitors and ULP devices should be engineered to always be optimized by a wireless power system.