German thin film thermoelectric specialist Micropelt says that its thermo-powered wireless sensor system is now ready for commercial evaluation and has launched an evaluation kit to enable potential customers to compare it to conventional battery technologies.
Micropelt's TE-Power Node uses just a few degrees of temperature differential to harvest energy to power a wireless sensor node, thus enabling battery-free operation. The company believes that its thermoelectric technology overcomes one of the main challenges preventing the further adoption of wireless sensor nodes, as their traditional reliance on batteries makes maintenance difficult and costly.
Micopelt's TE-Power Node evaluation kit consists of a 27 x 60mm aluminium baseplate carrying up to two Micropelt MPG-D751 thermogenerators, which power a Texas Instruments' MSP430/CC25xx mcu and a TI eZ430-RF2500 usb receiver module. Incoming variable thermo-voltage is converted into a battery-like constant voltage using a modified TE-Power Plus dc/dc converter, which supplies a constant 2.4V to charge a 100uF capacitor that feeds the duty cycle of the accompanying wireless system. Once attached to a suitable heat source, once a second the TE-Power NODE transmits temperature information on the thermogenerator's hot and cold sides, as well as the respective operating voltage, to a PC where it is displayed on a simple software user interface.
According to Dr. Joachim Numus, CTO of Micropelt: “Our measurements prove that an effective 3.5oC across the thermogenerator can drive this application. This can even be achieved through harvesting body heat. The node's flexibility will help our customers better understand the thermal path and why it can actually take 10 or 20oC difference to make it run.”
Added Buckard Habbe, VP business development: “We wanted to rove to our customers that thermoharvesters right now represent a viable energy supply for many applications, including most IEEE 802.15.4 base systems. Evan a few hundred microwatts supplied continuously can easily outperform a good set of batteries.”
Micopelt, which began as a research project by Infineon Technologies and Frauhofer Institute IPM Freiburg, was spun off in 2006. Whilst its standard products are currently produced at the company's pilot production plant in Freiburg, Germany, it is in the process of building a large-scale production facility in Sachsen-Anhalt. Micropelt expects to be able to produce some 10million devices by mid 2010.