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Rain Alarm / Rain Detector - This rain detector will give you a heads - up the instant it starts to rain, hopefully giving you time to close windows and bring in possessions. The battery - powered circuit draws virtually no current when the sensor is dry and the current consumption is low when the buzzer is activated so a couple of AA cells will last a long time. Alternately, a molded power supply with a simple voltage regulator to drop the voltage to 3 volts could be used. The circuit is basically a handy flasher circuit that operates well on only 3 volts using ordinary silicon transistors. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Rain Detector - This circuit uses a sensor made of a small piece of etched PC board and a simple SCR circuit to detect rain and sound a buzzer. The SCR could also be used to activate a relay, turn on a lamp, or send a signal to a security system. __ Designed by Aaron Cake
Rainwater Storage Gauge - Not only on ecologically grounds but also economically it makes sense to collect rainwater for use in the garden and increasingly for `grey water` domestic use. People who take rainwater collection seriously use large underground tanks for storage. The problem now arises, how can the water level be determined without lifting the tank hatch and peering in?__ Learning Electronics
Relative Humidity Sensor - This sensor is a capacitive element that changes value with humidity. By charging the sensor with a fixed current for a fixed time interval, a voltage is developed that is directly proportional to the sensor capacitance value. __ Linear Technology/Analog Devices App Note, Mar 16th 2010
Relative Humidity Sensor Digitizer - Charge Pump Based - Hygrometer Digitizer Has 0.3% Accuracy, Although Sensor Must Float Off - Ground. Humidity Sensor Determines Charge Delivered to A1 integrator During Each Charge Pump Cycle. Resultant A1 Output Ramp is Reset by Level Triggered C1 via Q1. Output Frequency, Taken at C1, Varies with Humidity__ Linear Technology/Analog Devices App Note, ,Mar 16th 2011
Relative Humidity Sensor Digitizer - Hetrodyne Based - Hetrodyne Based Humidity Transducer Digitizer Has Grounded Sensor, 2% Accuracy. Capacitively Sensed Hygrometer Beats Humidity Dependent Oscillator (C1) Against Stable Oscillator O1. Difference Frequency is Demodulated by Q1, Converted to Pulse Form at C2. Counters Scale Output for 0kHz to 1kHz = 0% to 100% Relative Humidity__ Linear Technology/Analog Devices App Note, Mar 16th 2010
Relative Humidity Sensor Digitizer - Time Domain Bridge Based - Humidity Transducer Digitizer Has Grounded Sensor, 1% Accuracy; Trim Scheme Allows Low Tolerance Sensors. Clocked Q1A - Q1B Configurations Produce Ramp Outputs. Q1A Ramp Slope Varies with Humidity Sensor Value, Q1B Ramp Represents Sensor’s Offset (0% RH does not equal 0pF). C1, C2 Digitize Ramp Times. Gate Extracts Time Difference, Presents 0 to 100 Counts Out for 0% to 100% Relative Humidity __ Linear Technology/Analog Devices App Note, Mar 16th 2011
Relative - Humidity Transmitter uses Single Logic IC - 11/08/01 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 ar Design by Shyam Tiwari, Sensors Technology Ltd, Gwalior, India
Remote humidity sensor needs no battery - 04/04/02 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 Design by Shyam Tiwari, Sensors Technology Private Ltd, Gwalior, India
K2LMG/W5EUT 1 - Wire Barometer - - 5/10 Volt Design Vrs 3 - This article describes details for constructing a 1 - Wire Barometer which will work on a Dallas Semiconductor Corporation 1 - Wire network. This design differs from the popular Version 1.1a in that it has more than twice the resolution. __ Designed by David W. Bray
Self - Heated Transistor Digitizes Airflow - 13 - Mar - - 96 EDN Design Ideas: A sensitive and reliable way to measure airflow is to exploit the predictable relationship between airspeed and the heat dissipated by a sensor exposed to the flow while being held at a constant temperature differential above ambient. The power required to maintain the elevated sensor temperature is proportional to the square root of the airspeed (King's law). The popular hot - wire anemometer uses this principle, but suffers from the disadvantage of using a relatively fragile airflow sensor, a thin metallic filament Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC
Sferics Detector - Schematic + info + pictures __ Designed by Lennie Zink
Sferics Detector - "Sferics"(also spelled "spherics") is short for atmospherics and refers to the crackling static in a radio produced by lightning. This receiver is tuned to an unused portion of the LF band provides enough sensitivity to detect lightning activity for hundreds or even thousands of miles. Best performance is achieved with an external antenna, but just a few yards of insulated wire is sufficient. A short whip mounted on the unit will work fine for picking up local storms. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Signal conditioning precisely indicates humidity - 02/02/98 EDN Design Ideas: The circuit in Figure 1 translates the level of humidity from0 to 100% into a stable, respective dc signal of0 to 100 mV. The heart of the circuit is IC 1, the iH3602 - C relative - humidity sensor (Microswitch/HyCal Sensing Products, Freeport, iL]. This device operates on 5V at 200 mA and provide as a dc output of0.8 to 4.0V Design by William Whitehead, Lafayette, CO
Simple Circuit Data - Logging Weather Station, Pt.1 - it's cheap and simple to build, operates completely unattended and will run for years on a set of AA batteries.__ SiliconChip
Simple Circuit Data - Logging Weather Station; Pt.2 - Last month we introduced our new Rain and Temperature - Measuring Weather Station, with all the electronics. This month we get into the nitty - gritty of building it - all the mechanical detail and then actual contstruction.__ SiliconChip
Simple Circuit Lightning Detector - Schematic + info + pictures __ Designed by Lennie Zink
Simple Circuit Rain Detector - Who needs a rain detector? How hard is it to look outside to see if it's raining? But a rain detector can come handy when you're distracted; it will save you the trouble of looking out the window every second when you want to catch the start of a rain storm, or cover some water sensitive stuff on your backyard. The following schematics are simple, but they can give design ideas or serve as a part of a more complex circuit like a computer weather data collection system. it all depends on your dedication, skill and expertise level__ hobbyteam @ hobby - hour.com
Small, portable altimeter operates from a single cell - 06/21/01 EDN Design Ideas: Some sports enthusiasts want to know altitude changes from an initial elevation. A small, lightweight, portable altimeter is easy to design using modern micromachined pressure transducers. inverting barometric pressure and compensating for nonlinearities in air - pressure changesseveral designs included, scroll to find this one Design by Todd Owen, Linear Technology Corp, Milpitas, CA
Snow Depth Alarm - The design of this system alerts a snowplow driver when the snow depth has exceeded four inches. A visible red LED packaged in a 10mm package is pulsed at a rate of about 50Hz with 10uS pulses. Twenty four inches away a phototransistor detects the light from the LED. The LED and the phototransistor are housed in a section of ½ inch PVC pipe, forming a waterproof seal. . . . Hobby Circuit designed by Dave Johnson P.E. - July, 2006
Solar Powered Wireless Weather Station - it's based on PIC AXE processor and "wirelessly" transmits temperature and humidity data to a receiver up to 200 metres away.__ SiliconChip
Solar Radiation Meter - Schematic + info + pictures __ Designed by Lennie Zink
Sudden ionospheric disturbance (SID) receiver - The AAVSO SiD Program consists of solar observers who monitor very low frequency (VLF) radio stations for sudden enhancements of their signals. Earth's ionosphere reacts to the intense X - ray and ultraviolet radiation released during a solar flare. The ionospheric disturbance enhances VLF radio propagation. By monitoring the signal strength of a distant VLF transmitter, sudden ionospheric disturbances (SiDs) are recorded and indicate a recent solar flare event. __ Contact AAVSO SID Program
System Monitor with Instrumentation - Grade Accuracy Used to Measure Relative Humidity - A psychrometer is a type of hygrometer, a device that measures relative humidity. it uses two thermometers, one dry (dry bulb) and one covered in a fabric saturated with distilled water (wet bulb). Air is passed over both thermometers, either by a fan or by swinging the instrument, as in a sling psychrometer. __ Linear Technology/Analog Devices App Note, Jan 30th 2012 |
