The MCC site sponsor NXP has recently released new single-chip wireless microcontrollers. What really intrigues me about these devices is their ability to work with low power. Low enough that their wireless links can work off of harvested energy.
The latest NXP introduction is part of its JN5100 series. These devices integrate a low-power 32-bit MCU with a full 802.15.4-complient RF transceiver. There are several devices in the series, some targeting ZigBee, some for RF4CE, and some for NXP's own JenNet-IP protocols that provide a link between IPv6 networks and a self-healing mesh. The new devices are currently sampling with lead customers and will be available (along with evaluation kits) from distributors this coming January.
One of the things that got my attention in the press release, though, was a demonstration video showing a light and switch that used the devices for wireless lighting control. The light, naturally, got the power for the MCU from the AC mains that also powered the bulb. The switch, however, had no wiring. It got the power for the MCU from the user. Tripping the switch generated enough energy to power up the MCU, establish its network connection, and send commands to the light wirelessly.
Using only the mechanical energy of actuation, this switch can wirelessly communicate a message to another system element, such as a light.
Cherry, a division of ZF Electronics, has developed the energy harvesting switch used in the demo. The switch is capable of generating as much as 0.5 mWs (milliwatt seconds, or milliJoules) of electrical energy, which is only enough to power the wireless MCU (15mA when transmitting) for a fraction of a second. But that fraction is more than long enough to get the message across.
These low-power wireless MCUs and their like open up a host of potential applications well beyond the ability to create lighting systems where the switches don't need any wiring connections. They can also be used for environmental sensors that get their energy from environmental heat, light, light, or motion that might otherwise go to waste. No batteries needed; just an energy source.
There are lots of energy harvesting opportunities around us. Some systems can capture RF energy from broadcast radio and television. Others use the sap of trees as part of an electrochemical reaction to generate electricity from living plants. Vibration, bending, compression, and virtually every other kind of mechanical operation can be used to generate a small amount of electricity. Devices like these ensure that even that small amount is enough to get a message out to the network.
What kind of message would your design send, and what would your source of energy be?
Rich Quinnell 11/27/2012 12:58:55 PM User Rank Blogger
Re: Remote (but nearby) Sensor Applications
AD, good point. I had forgotten about handling thermal shock and rapid temperature transitions.
That said, I have run into a number of military applications recently where the operating temeratures required were somewhat less stringent. These were for systems that needed human operation and the idea was (I suppose) that the equipment only had to handle a human-livable environment when being operated, since the operators had to live there too.
Rich Quinnell 11/27/2012 12:56:10 PM User Rank Blogger
Re: No power, is coming soon ....
nemos, along with the lower power of MCUs are advances in low power RF and in energy harvesting. I find the last to be particularly fascinating. You can get enough power out of vibration, heat, solar, and even ambient EMF in the form of radio and television signals to power an MCU and RF in brief spurts of activity that can serve as sensor networks. Pretty cool, IMHO.
antedeluvian 11/26/2012 2:54:35 PM User Rank Blogger
Re: Remote (but nearby) Sensor Applications
Rich
Not only do military devices have to operate at environmental extremes, they have to be able to transition very rapidly from one extreme to another. I seem to remember one fighter jet had to go from 40 degC to -40degC in a matter of a minute or so, to say nothing of the air pressure change.
Rich Quinnell 11/26/2012 2:49:47 PM User Rank Blogger
Re: In the switch
northstar, I haven't seen a vibration spec for this switch yet, but I suspect that an earthquake won't actually trigger the switch. For one thing, the moment arm on the switch is pretty short and the mass is distributed pretty closely around the pivot point, so there would have to be a lot of up-and-down movement for the slight imbalance from the switch handlie's sticking out to trip the switch. And if the house is shaking that much, the lights coming on are the least of your problems. More likely the lights will be craching to the floor with that kind of shock.
Rich Quinnell 11/26/2012 2:45:15 PM User Rank Blogger
Re: Remote (but nearby) Sensor Applications
northstar, from my experience working on military projects, I would say the biggest difference between military devices and commercial/industrial ones are the environmental requirements. Most military gear I was involved with had to operate in (or at least survive) temperatures from-55 to +125C. Most commercial devices are rated at 0 to +40C. After all, who will be watching their big-screen TV at below-freezing temperatures?
As to security and the like, the military applications for sensors and the like are part of larger systems with a lot of security features built in at a higher system level. Still, there will be need for things to help prevent reverse engineering, tampering, and remote intrusion. So, wireless devices like this will probably not find a home in military systems unless the security issue can be addressed.
Nemos 11/26/2012 12:40:02 PM User Rank System supervisor
No power, is coming soon ....
A great point came out of your post Rich , reducing the power consumption of a MCC makes the possibility to see soon systems that will not need batteries or external power supply more real.
northstar 11/22/2012 10:51:58 PM User Rank Program Manager
Re: In the switch
What would happens in case of vibrations? Is this enough to trigger a switch on/off? I thinking to vibrations from an earthquake or maybe from a drilling machine nearby the house. Is this enough to make your house like a Christmas tree?
northstar 11/22/2012 10:46:59 PM User Rank Program Manager
Re: Remote (but nearby) Sensor Applications
It is amazing to see how innovative can be the human mind. Not always following a "good" path, but still ... very interesting. The security is so low with all this new devices, that I expect for a lot of those scenarios to be highlighted in next years.
I wonder, sensors used for military vehicles are much different than those ones?
Rich Quinnell 11/21/2012 4:41:40 PM User Rank Blogger
Re: Remote (but nearby) Sensor Applications
andyk1, size is a challenge, but I don't see that as being insurmountable. What I would be more concerned about is longevity. The human body is a terribly harsh environment for electronics systems. Not only are there lots of acids and enzymes that can attack electronic devices, there are bacteria, antibodies, and other biologically active attackers that can work their way into practically anything. Creating an electronic device that can survive that environment for any substantial length of time (ie, years) seems like it would be very difficult.
andyk1 11/21/2012 11:29:38 AM User Rank Program Manager
Re: Remote (but nearby) Sensor Applications
I think it could be usefull for tooth implanted dental devices like this nice thing: a sensor that painted on your tooth , and senses some kind of bacteria and sends a warning:
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