[Alanson Sample] as well as [Joshua R. Smith] have been experimenting with wireless power transfer for their sensing platform. Their microcontroller of option is the MSP430, which we utilized on our e-paper clock. They selected it particularly for its capability to work with low voltages as well as they discus its certain habits at different voltages. The very first part of their paper utilizes a UHF RFID visitor to transmit to the sensor’s four stage fee pump. They added a supercap to supply sufficient power for 24 hours of logging while the node isn’t near a reader. For the second half of the paper, they utilize a UHF antenna created for digital TV with the exact same circuit as well as directed it at a television tower ~4.1km away. It had an open circuit voltage of 5.0V as well as 0.7V across an 8KOhm load, which works out to be 60uW of power. They linked this to the AAA battery terminals of the thermometer/hygrometer visualized above. It worked without issue. The thermometer’s draw on a lab power supply was 25uA at 1.5V.

It’s an fascinating technique to powering devices. Do you have an application that needs something like this? For a lot more on wireless power, checkout this earlier publish on scratch building RFID tags.

[via DVICE]