741 Based Light Sensor: CdS photocell used for light/dark
controlled relay |
Circuitry for inexpensive Relative Humidity Measurement:
National Semiconductor Application Notes,04-Nov-1995
|
Dual Comparators Stabilize Proximity Detector: 02/16/98
EDN-Design Ideas |
Infrared Body heat Detector: |
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... . |
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. . |
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. . |
Signal Conditioning Precisely indicates Humidity: 02/02/98
EDN-Design Ideas |
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... |
Tiny Dew Sensor: |
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.. |