µ[micro]electronics info

A weblog focused on interesting circuits, ideas, schematics and other information about microelectronics and microcontrollers.




Because I have not tested all electronic circuits mentioned on this pages, I cannot attest to their accuracy; therefore, I do not provide a warranty of any kind and cannot be held responsible in any manner.

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Infrared repeater

MCU based infrared repeater allow to control an A/V equipment that is behind a wall.

Power is supplied to CON1 from a cheap Alcatel phone charger that outputs stabilized 12V, passes through reverse voltage protection diode to IC1 that outputs 5V VCC. Atmel AVR microcontroller runs from 4MHz ceramic resonator Y1, C3+R1 form a reset circuit. Infrared detector (TSOP1738 in my case) is connected to INT0 input, C1+R2 are for detector power filtering. There is a green indicator LED D2 connected to PB2, and two 940nm infrared leds D1,D3 connected to PB3 via driver transistor Q1. R6 limits current through IR leds, and C2 is good to have if the IR diodes are at the end of long wires. I have separate board with R5,Q1,D1,D3,R6,C2 at the end of cable, but you may choose to build the whole circuit on single board and lengthen the wire that goes to detector.
Infrared repeater

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