About Sensors

This page contains an archive of all entries posted to Gadget Freak in the Sensors category. They are listed from oldest to newest.

Radio is the previous category.

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October 16, 2007

How to build an infra-red remote control

The infra-red remote control transmits a tone using an infra-red LED. This tone is decoded by the receiver.

remote1.JPG

Continue reading "How to build an infra-red remote control" »

June 16, 2008

Solar radiation and a delta-sigma ADC

kipp and konen manual.jpgA device to measure the rays all around us, but it doesn't come under the 'tin-foil helmet' category. File it under delta-sigma ADC - it is a very detailed Solar Server project to measure the solar radiation striking Earth ("insolation"), recording the daily data to a file, which is then emailed.

The device used for measuring daily insolation is designed by Wichit Sirichote in Thailand. He introduces the project, thus:

"The total solar radiation is measured by a Kipp & Zonen CM11 pyranometer (pictured). The EMF output of 5.14 uV/W/m2 is fed to the 24-bit resolution Delta-Sigma A/D converter, LTC2400. The microcontroller circuit built with a PIC18F2550 controls the A/D converter and provides one second time base for data sampling period. The insolation is computed by accumulated summation of the converted data in a whole day.

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August 21, 2008

Circuit Design Idea - Precision capacitive-sensor interface suits miniature instruments

circuit - Precision capacitive sensor interface.jpgHere's another newly-uploaded Circuit Design Idea designed to give circuit building inspiration (click on the circuit diagram to expand it).

It covers developing a voltage proportional to the value of a capacitive sensor and transmitting these readings via a LVDS interface.

The Design Idea begins:
In some applications of capacitive sensors, the instrument's front end must be small enough to fit into a narrow space. Figure 1 shows a precision capacitive-sensor interface for such use. The square-wave output from a low-voltage 555 timer, IC1, constantly triggers the precision one-shot, IC2, to produce quasistable outputs for time periods T1 and T2, which are proportional to external timing capacitance: T1=KR0(CS+C0), and T2=KR0CS, where K is the multiplier factor.

Continue reading "Circuit Design Idea - Precision capacitive-sensor interface suits miniature instruments" »