Ricardo Jimenez, electronics professor at Imperial Valley College in Imperial, Calif., received a BSEE from the Technological Institute of Durango, Mexico. Email address: jimenez-ricardo@sbcglobal.net Web site: http://www.imperial.cc.ca.us/
4 results found for Ricardo Jimenez, displaying items 1 - 4
March 17, 2005[Ideas For Design] Measure Relative Humidity With A PIC MCU
A relative humidity meter can be built using a sensor with a capacitive response and a PIC microcontroller (MCU), as shown in the figure. The capacitance range of the sensor, the HS1101 from Humirel (www.humirel.com), varies from 162 to 202 pF. Functioning as an oscillator, a TLC555 CMOS timer performs the conversion from capacitance to frequency. The timer's frequency equation is given by: F = 1.44/(RA +...
February 3, 2005[Ideas For Design] Just One Microcontroller Pin Sets Programmable Timer's Interval
Most digital timers require a set of dip switches or rotary BCD encoders to preset their interval. But those techniques consume eight or more inputs from a microcontroller's (MCU's) I/O lines. To alleviate the problem, this circuit forms a digital timer that only requires one input pin of the PIC16F872 MCU to adjust its interval (see the figure). The MCU performs all of the functions, a-d converting, timing, and decoding to drive...
