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Saturday, September 28, 2013

Infrared Remote Tester

Suitable for any Infrared emitting device, 3V battery supply

A very simple device allowing a quick check of common Infra-red Remote-Controls can be useful 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 push buttons 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.

Circuit Diagram:

Infrared Remote Tester Circuit Diagram

Parts:

R1 = 470K
R2 = 47R
D1 = LED Any Type
Q1 = Photo Transistor
Q2 = BC327
B1 = 3V Battery or 2 AA cell

Notes:

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.
SW1 will be SPST Toggle or Slider Switch

Source : www.redcircuits.com

Friday, March 29, 2013

R tC Servo Tester Circuit

Here’ s a design circuit for servo signal is a simple digital pulse. It spends most of its time at a logic low (0 V). About every 20mS it goes logic high (3 to 6 VDC) and then quickly goes low again. It is this tiny window of logic high time, called the pulse width, that gets the attention of the servo. Here’s the figure of the circuit;

Please refer to the drawing. The period labeled "A" is called the frame rate. In the example it is repeated every 20mS (50 times per second), which is quite typical for most radio systems.Modern servos define center as a 1.5mS pulse width, as shown by detail "B" in the drawing. Full servo rotation to one side would require that this pulse width be reduced to 1.0mS. Full rotation to the other side would require the pulse width to increase to 2.0mS. Any pulse width value between 1.0mS and 2.0mS creates a proportional servo wheel position within the two extremes. The frame rate does not need to change and is usually kept constant.

The servo will not move to its final destination with just one pulse. The servo amp designers had brilliantly considered that multiple pulses should be used to complete the journey. This little trick reduces servo motor current draw and it helps minimize erratic behavior when an occasional corrupt signal is received. To move the servo, you must repeat the pulse every few milliseconds, at the chosen frame rate. Modern R/C systems use a 40Hz - 60Hz frame rate, but the exact timing is not critical. If your frame rate is too slow, your servos movement will become rough. If the rate is too fast the servo may become very confused.

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Saturday, September 28, 2013

Infrared Remote Tester

Friday, March 29, 2013

R tC Servo Tester Circuit