IR Remote-Control Checker

Posted on Feb 6, 2014

R2_47R 1/4W Resistor D1_LED (Any dimension, shape and color) Q1_Infra-red Photo Transistor (Any cheap type) Q2_BC327 45V 800mA PNP Transistor SW1_SPST Toggle or Slide Switch (Optional, see Note) B1_3V Battery (2 x 1. 5V AA, AAA or smaller type Cells in series) A very simple device allowing a quick check of common Infra-red Remote-Controls can be us

IR Remote-Control Checker
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eful to the electronics amateur, frequently asked to repair or test these ubiquitous devices. A reliable circuit was designed with a handful of components: the LED will flash when any of the Remote-Control pushbuttons will be pressed. The side of the Remote-Control bearing the IR emitting diode(s) must be directed towards the Photo Transistor (Q1) of the checker circuit: maximum distance should not exceed about 20 - 25cm. Current drawing of the circuit is less than 1mA when the LED illuminates and 0mA when no signal is picked-up by the Photo Transistor: therefore, SW1 can be omitted. R3_10K 1/4W Resistor R4_1K 1/4W Resistor D1_LED any type and color D2_1N4148 75V 150mA Diode IC1_4001 Quad 2 Input NOR Gate CMos IC Q1_BC337 45V 800mA NPN Transistor SW1_SPDT Toggle or Slide Switch (Optional) RL1_Relay with SPDT 2A @ 230V switch Coil Voltage 12V - Coil resistance 200-300 Ohm Two steel rods of appropriate length The shorter steel rod is the "water high" sensor, whereas the longer is the "water low" sensor. When the water level is below both sensors, IC1C output (pin #10) is low; if the water becomes in contact with the longer sensor the output remains low until the shorter sensor is reached. At this point IC1C output goes high, Q1 conducts, the Relay is energized and the pump starts operating. Now, the water level begins to decrease and the shorter sensor will be no longer in contact with the water, but IC1C output will be hold...

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