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							741 Based Light Sensor:  CdS photocell used for 
							light/dark controlled relay  | 
						
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							Circuitry for inexpensive Relative Humidity 
							Measurement: National Semiconductor Application 
							Notes,04-Nov-1995 | 
						
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							Dual Comparators Stabilize Proximity Detector: 
							02/16/98 EDN-Design Ideas  | 
						
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							Infrared Body heat Detector: | 
						
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							Low cost relative humidity transmitter uses single 
							logic IC: 11/08/2001 EDN - Design Ideas /  
							The low-cost percentage-relative-humidity radio 
							transmitter in Figure 1 operates in a cold-storage 
							warehouse for vegetable storage at temperatures of 1 
							to 5 C. It is generally difficult to collect such 
							data from a low-temperature area with high humidity 
							and low illumination. The transmitter design is 
							simple: It uses a readily available, capacitor-type 
							percentage-relative-humidity se... . | 
						
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							Measure humidity and temperature on one TTL line: 
							08/30/2001 EDN - Design Ideas / By combining the 
							responses of an Analog Devices (www.analog.com) 
							AD590 temperature sensor and a Humirel (www.humirel.com) 
							HS1101 humidity sensor, you can generate a single 
							TTL-level signal containing information from both 
							sensors (Figure 1). This design uses a 74HC123 
							monostable multivibrator, IC1, to form a 
							free-running oscillator. . | 
						
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							Remote humidity sensor needs no battery: 
							04/04/2002  EDN - Design Ideas / Using ac-line power 
							sources and batteries for remote humidity sensors is 
							undesirable because these sources can be troublesome 
							if you mount them in inaccessible points, such as 
							smokestacks, cold-storage chambers, or darkrooms, 
							where maintenance is difficult and inconvenient. 
							Figure 1 shows a simple way to remove the power 
							source from the humidity-sensor circuit. . | 
						
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							Signal Conditioning Precisely indicates Humidity: 
							02/02/98 EDN-Design Ideas  | 
						
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							Simple Circuit Uses Optical Fiber To Send 
							RelativeHumidity Data : 04/01/02 Electronic 
							Design - Ideas for Design / The circuit shown in the 
							figure measures relative humidity in air at the low 
							temperatures found in applications like cold storage 
							of food items and greenhouses. Instead of using 
							electrical signal cables that...   | 
						
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							Tiny Dew Sensor:  | 
						
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							Transmitter senses triple relative humidity figures: 
							09/26/2002  EDN - Design Ideas / The circuit in 
							Figure 1 is a triple, relative-humidity sensor and 
							radio transmitter. Sensors 1 and 2 form two gated 
							oscillators with natural frequencies of 10 and 5 
							kHz, respectively, at relative humidity of 50%. The 
							gated oscillators use variable resistances R2 and 
							R3, respectively. Together, these two oscillators 
							generate FSK-modulated outputs at output of IC1B, 
							Pin 6.. |