DURING THE SPRING, Infineon Technologies, Microwaves & RF, and LS Research LLC had the opportunity to sponsor a design contest titled, "Get Smart! Get Wireless!" The objective of the contest was to simplify a wireless design using Infineon's SmartLEWIS RX TDA5230 receiver. This receiver offers digital baseband signal processing to significantly reduce current consumption and time to market. It also eliminates the need to write any real-time embedded software for the microcontroller. By implementing this receiver, three winners succeeded in creating lowpower wireless designs that earned them cash prizes of $3000 each.
The TDA523x series offered the designers a head start, as it is well suited for short-range, low-power wireless systems like remote and passive keyless entry (RKE and PKE), tire-pressure monitoring (TPM), remote control, alarms, and low-bit-rate communications. This family of autonomous ASK/FSK receivers covers 302 to 320 MHz, 433 to 450 MHz, and 865 to 870 MHz. It boasts a third-order intercept point of -22 dBm and -33 dBm output power at 1-dB compression. In power-down mode, standby current is just 1 A. The receiver offers sensitivity below -108 dBm (ASK). To save power, the SmartLEWIS TDA523x receiver will scan for any news meant for the system and only wake it up when something relevant is available.
Two individuals collaborated in the design that won first place. Ken Hopwood and Inaki Zuloaga are Software Engineers at ProSoft Technology. For their application, "Smart House Array of Inexpensive Sensors for Home Automation and Energy Savings," they proposed a low-cost Smart House system to monitor in-house variables like temperature, energy consumption, doors status, plant humidity, and more (see Figure). Although there are several wireless standards for home automation, they typically operate as mesh networks helped by powerful microprocessors. At the end, coordinating the resulting nodes can be expensive for the customer. The average node cost of a mesh network device for home automation is $50. By exploiting the features of the TDA5230, Hopwood and Zuloaga were able to create a network of sensors that could monitor variables in an average-sized house with a cost of less than $10 per node if mass produced.
When asked what inspired them to come up with this design idea, Hopwood and Zuloaga answered, "We are concerned about the effects of excess energy use on the environment. Although there are many companies working on energy-saving solutions, none of them are targeting customers that cannot afford to pay hundreds or thousands of dollars for an energy-saving system. In order for such a system to be effective and make a difference, it needs a larger number of measurement nodes and to be priced so that most households can afford it." They plan to use their prize money to pay for their development tools and finance the continuation of the project.
The second-place winner, Robert Lake, is a Developer at LRV Consulting. He created an "Automobile Child Seat Alert" in which a remote receiver would be triggered after a combination of events happened. An alternate receiver mounted in the vehicle could then sound the horn. The TDA5230, which is designed so that it can be attached to a keyring, will alert the driver that the child is still in the car seat. The possibilities of adaptations to the receiver could take into account that the receiver has not received data from the transmitter for a period of time after the last data indicated that the child seat was still occupied.
Lake was inspired to create this design by his wife Vickie, who could not understand why technology was not available to help notify drivers that their child was still in the child seat. He then started to design a car seat monitor that could be retrofitted into existing car seats. When asked what he will do with his prize money, Lake answered, "As Vickie, my wife, suggested the child seat, we will split the money. My half will go to ham radio equipment, 73."