Serial Infrared Remote Controller:  a simple, cheap device that can be connected to any serial port to control most components that have infrared remote controls, includes schematics for receiver and transmitter (added 4/02)

Serial Port Controller Infrared Transmitter (PIC16F628):  (electronic circuit added 7/03)

Simple Infra-Red Detector:  (electronic circuit added 4/05)

Simple Infrared Remote Control:  (electronic circuit added 7/03)

Simple IR Detector:  (circuit design added 11/06)

Simple IR Transmitter Circuit:  (electronic circuit added 4/05)

Stable 40kHz Clock:  (electronic circuit added 7/03)

Supply Voltage Indicator:  This simple and slightly odd circuit can clearly show the level of the supply voltage (in a larger device): as long as the indicator has good 12 volts at its input, LED1 gives steady, uninterrupted (for the naked eye) yellow light. If the input voltage falls below 11 V, LED1 will start to blink and the blinking will just get slower and slower if the voltage drops further giving very clear and intuitive representation of the supply's status. The blinking will stop and LED1 will finally go out at a little below 9 volts....  (added 10/05)

Telephone call meter using calculator and COB #2:  In this circuit, a simple calculator, in conjunction with a COB (chip-on-board) from an analogue quartz clock, is used to make a telephone call meter. The calculator enables conversion of STD/ISD calls to local call equivalents and always displays current local call-meter reading.
The circuit is simple and presents an elegant look, with feather-touch ....    (added 1/065)

Temperature Controller keeps IR Detector at 8ºK:  01/07)/99 EDN-Design Ideas / (added 6/06) [Note:  File contains multiple circuits scroll to find this circuit]  Sensitive infrared array detectors must operate at a low temperature to avoid thermally generated dark current throughout the photoconductive elements. This requirement is particularly true for SiAs array detectors, which need cooling to near liquid-helium temperatures. Furthermore, the sensitivity of these detectors can be temperature-dependent. The optimal operating temperature for a long-wavelength IR camera is about 8ºK. This temperature must remain constant despite changes in the radiation level falling on the array, in the liquid helium level as it boils away, and in the orientation of the Dewar flask....

Temperature Measurement Scheme uses IR Sensor and Sigma Delta ADC:  04/03/03  EDN-Design Ideas / (added 7/03) Many noncontact temperature-measurement systems use infrared sensors, such as thermopiles, which can detect small amounts of heat radiation. Biomedical thermometers that measure the temperature of an ear or a temple use non-contact temperature measurement, as do automotive-HVAC systems that adjust temperature zones based on the body temperature of passengers...

Universal Infrared Controller for a PC:  This simple circuit allows you to record any Infrared remote control signal on your PC, and then play it back. This is particularly useful if you want to control appliances such as TVs, VCRs, CDs etc. from your computer. The device simply connects to the parallel port of your PC. You can also use this circuit to analyze the waveform from any Infrared remote control. This circuit was originally published in Electronics Australia, September1998 (added 4/02)

Universal Infrared Remote Control:  Infrared remote based on Atmel 89C2051 (added 6/06)

Using the MCP2120 for Infrared Communications:  Microchip Application Note Published 4-Jun-01   (app note added 2/06)

Very Stable 40kHz Generator:  (electronic schematic / circuit added 4/02)