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Sensors
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RF Modules
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 Sometimes in embedded design you may want to go wireless. These RF remote Transmitter/Receiver modules can easily be interfaced to PIC microcontroller remote projects. The use of RF technology enables the user to log various readings of remotely placed sensors, to control automation components without needing to point or even have a line of sight of the component. The RF signal is captured by an RF receiver, which then relays the command to the component in question, no matter where the component is located.
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The Dallas Real Time Clock
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 The Dallas DS1307 is a low power Serial Real-Time Clock (RTC) that can easily be interfaced to a PIC. It is a full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I2C, bidirectional bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. The DS1307 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply. Timekeeping operation continues while the part operates from the backup supply.
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The Dallas Temperature Sensor
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The Dallas DS18S20 is a one wire Temperature sensor that can easily be interfaced to a PIC micrcontroller. Data derived from the DS18S20 is a 9 bit centigrade temperature measurament. As mentioned the temperature sensor communicates over a 1 wire bus that requires only one data line and ground for communication. The DS18S20 once interfaced to a PIC could be sampled at 1 second intervals and the result displayed on a standard LCD.
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The Hitachi LCD Display
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 Liquid crystal displays (LCD) are now available which are inexpensive and are simpe to use. They come 16 to as many as 40 characters wide and 1,2, or 4 lines. The 2 line by 16 character display is controlled by a Hitachi HD44780 LCD controller chip which is surface mounted on the back side of the display module's printed circuit board. The HD44780 display controller is commonly used an a variety of liquid crystal displays made by manufacturers such as Hitachi, Optrex, Amperex, Densitron and Epson.
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The Sensirion Temperature/Humidity Sensor
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 The Sensirion SHT15 is a two wire combined Relative Humidity and Temperature 8/12/14 bit digital sensor. The sensor is a surface mountable device and is easily interfaced to a PIC microcontroller.
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The RF Solutions GPS Module
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 RF Solutions 41-MLR Global Positioning System (GPS) module outputs data in RS232 and LVTTL serial format. The GPS module is easily interfaced to a PIC microcontroller USART interface.
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The Analog Devices Accelerometer
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 The Analog Devices ADXL202 is a low cost, low power, complete 2-axis accelerometer with digital output, all on a single monolithic IC. It will measure acceleration with a full scale range of plus or minus 2g. The ADXL202 can measure both dynamic acceleration (vibration) and static acceleration (gravity). The outputs are analog voltage or digital signals whose duty cycles (ratio of pulse width to period) are proportional to acceleration. The duty cycle outputs can be directly measured by a microcontroller counter.
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