Category Archives: Infrared

40khz IR Tester

Use this circuit to test if the light coming from your 40khz IR emitter is really emitting the right frequency. The schematic says to use a GP1U5X ir module, but probably any 40khz detector module will work.Parts:R1 270 ohm resistor
L1 Visible LED
S1 On/Off Switch
IR Module Sharp GP1U5X IR Detect Module (or compatible)

Remote IR Terminal

Some projects need a control panel, but are in situations which make that cumbersome. Unlike bench equipment, which would be useless without built-in readouts, other control devices could use interfacing just to alter a few settings or take occasional readings. This device’s first job will be interfacing to my hydroponic controler.

This unit provide 2 way IR communications using a numeric keypad and an LCD display. Data is sent and recieved in ASCII with no regard to what the data means to any particular device.

The ASCII data still needs some form of encoding. For this I chose [url=http://mondo-technology.com/tricks.html]10-pulse coding[/url] of 38Khz IR using a nifty 99 cent receiver chip , TSOP4838 The transmitting is done with a straight IR LED with both carrier and coding done in software.

As you can see from the diagram below, the membrane switch and LCD display use up quite a few I/O lines even with some sharing of signals. This required the use of a larger (28pin) PIC for this controller. However, it means that the target device it controls needs only 2 I/O lines for sending and receiving the IR data. Although functional at this time, some features and nicities need to be added later.

Here is the current state of the [url=http://www.circuitdb.com/download.php?fileID=182]Source file[/url].

[img:41c63d2642]http://www.circuitdb.com/download.php?fileID=183[/img:41c63d2642]

Copyright 2006 [url=http://mondo-technology.com/]Luhan Monat[/url]Parts:IR LED and receiver:
TSAL-6200 Vishay IR LED 940nm
TSOP-4838 Vishay IR Reciever 940nm 38khz

Remote IR Control Panel

Some projects need a control panel, but are in situations which make that cumbersome. Unlike bench equipment, which would be useless without built-in readouts, other control devices could use interfacing just to alter a few settings or take occasional readings. This device’s first job will be interfacing to my hydroponic controler.

This unit provide 2 way IR communications using a numeric keypad and an LCD display. Data is sent and recieved in ASCII with no regard to what the data means to any particular device.

The ASCII data still needs some form of encoding. For this I chose [url=http://members.cox.net/berniekm/tricks.html]10-pulse coding[/url] of 38Khz IR using a nifty 99 cent receiver chip ,TSOP4838. The transmitting is done with a [url=http://members.cox.net/berniekm/Hot_Parts.html]straight IR LED[/url] with both carrier and coding done in software.

As you can see from the diagram below, the membrane switch and LCD display use up quite a few I/O lines even with some sharing of signals. This required the use of a larger (28pin) PIC for this controller. However, it means that the target device it controls needs only 2 I/O lines for sending and receiving the IR data. Although functional at this time, some features and nicities need to be added later.

[img:afa4d84a8a]http://www.circuitdb.com/download.php?fileID=151[/img:afa4d84a8a]

Here is the current state of the [url=http://www.circuitdb.com/download.php?fileID=150]Source file[/url].

Copyright 2006 [url=http://members.cox.net/berniekm/]Luhan Monat[/url]

Infrared Remote Control Tester

This is a fairly easy circuit that can be used to test TV and VCR remote controls. The infrared detector module (GP1U52X) (Radio Shack 276-137) produces a 5 volt TTL pulse train corresponding to the digital code of the particular remote control key pressed. In the lower circuit, the module output is normally low with no signal received and becomes a positive going pulse train when a signal is present. Other detector modules are available that have an inverted output as shown in the upper drawing which is the type I used, but I don’t have the part number, I believe it was removed from a VCR. The pulse sequence represents the digital code of the particular key pressed along with possible manufacturer information. As the pulse train occurs, the 4.7uF capacitor is charged to about 3 volts and the capacitor voltage minus a diode drop appears across the 470 ohm resistor yielding a collector current from the 2N3904 or 2N3906 of about 5 milliamps. The collector current of the first stage flows into the base of the output transistor (MJE34 or 2N3053) which delivers around 250 mA into the indicator lamps. When the pulse train ends, the capacitor slowly discharges through the base of the first stage transistor allowing the Xmas tree lights to remain on for a about 1 second. The little Xmas lamps will operate over a wide voltage range, so you can use bulbs from almost any string, but bulbs from shorter strings (35 or less) will probably last longer operated at 5 volts.

The circuit can be powered from a small 9-12 volt DC, 250 mA or greater wall transformer. It may also need an additional 1000 uF filter capacitor across the DC output if the wall transformer does not have a built in capacitor. For use with a 9 volt battery, the incandescent lamps can be replaced with a regular LED and 680 ohm resistor and the output transistors can be replaced with small signal transistors (2N3904 or 2N3906). The total current drain will be about 25 mA with the LED lit, and 15 mA standby when the LED is off.

Copyright 2006 Bill Bowden