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Remote sensing with two wires and daisy chained sensors

[Category : - HEALTH- Fitness- Security and alarms]
[Viewed 2667 times]

This invention is used to measure physical parameters such as temperature, humidity, air speed, switch open/closed status, light level and any reading that can be converted to resistance or voltage. It can be used for controlling the temperature of a heating pad or an electric blanket, detecting an alarm condition in a building, controlling soil moisture in a garden and many other control and monitoring applications.

A controller consisting of a PC or microprocessor is connected to a pair of wires. The sensors are then connected in series with the one of the wires in a daisy-chain fashion. The second wire serves as a ground connection for each sensor.

The controller applies voltage to the first pair of wires connected to the first sensor. The first sensor delays by an amount related to the value of the parameter being measured and then applies power to the second sensor etc. until all sensors are actuated. As each sensor is powered, the amount of current drawn from the controller increases. The time from power application to current increase is read by the controller, and knowing the characteristics of the sensor, the physical parameter value can be determined.

For example, if the input is connected to a thermistor, a device whose resistance changes with temperature, and the thermistor is connected to a capacitor, a comparator and an output voltage switch. The time from application of power and switching power to the next device will be determined by the temperature of the thermistor.

The temperature sensing application is suitable for zone control of a house or controlling the temperature of a heating pad or blanket.

Additional information: Link

Financial information

I would like to sell the patent outright.

All design files for the heating pad application will be provided to the buyer. Files include schematic diagrams, bills of materials, PCB Gerber files, microprocessor source code and test data. All are provided with out warranty.

Possible products:
Intrusion alarms
HVAC zone controls
Heat pad and heating blankets
Pet bed heaters
Garden soil moisture monitor

Patent publications:

US 7412347

Asking price:

30,000 USD

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Viewed: 2667 times

Seller:

rshwd (United States)

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