January 2006, Issue 186

Electronic Scarecrow

For the past 12 years, I’ve lived in a small rural section of an otherwise urban area. A forest abuts my backyard. Although there have been many advantages to living in a natural setting, one of the more annoying problems has been the ever-increasing number of deer that have come to forage in the area. Several times a day, for instance, I see deer munching in my yard.

Most of the conventional methods for keeping deer off my property no longer work because these foragers can jump over fences and they don’t seem to mind the foul taste and smell of repellents. One of my neighbors once got so frustrated that he installed an electric fence in his yard, but that didn’t deter the deer either! It appears that deer will eventually adapt to obstacles they encounter on a regular basis. The only way to keep deer away is to create deterrents they’ll never adapt to.

My Electronic Scarecrow system is a great solution (see Photo 1). When an animal is detected, the system’s base station activates countermeasures like loud sounds and garden sprinklers to scare it away. The system includes four remote stations designed around Freescale Semiconductor MC13192 SARD boards. Each board is connected to several sensors that transmit signals to the evaluation board on a base station, which features an LCD, push button controls, an X10 power line transmitter interface, and a serial port for downloading code updates and sound files. The remote and base stations are built around MC13192 2.4-GHz transceivers controlled by Freescale MC9S08GT16 microcontrollers (see Figure 1). I obtained the Freescale parts when I entered the 2005 Freescale Wireless Design Challenge.