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Recent content by beckhamho

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    checking sequence using If statement

    Hi alexan_e, Thanks for the reply. how about the while loop? while((input(IR1) && input(IR3)) ^ (input(IR2) && input(IR4))); should be no problem?
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    checking sequence using If statement

    Hi andre_teprom, ok,basically my stuff works like this: IR1,IR2,IR3 and IR4 is always in high stage(1). I wan to write a program when: IR1 and IR3 goes low(0) , IR2 and IR4 stay high(1) then check by while loop,if TRUE then goes to next if statement IR1, IR2, IR3 and IR4 = 0 check by while loop...
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    checking sequence using If statement

    Hi I am trying to check the sequence using if statement. first : IR1 and IR3 goes low and IR2 and IR4 stay high check by while loop, if it is true then go to next if statement. second : IR1 ,IR2,IR3 and IR4 all goes low. check by while loop, if it is true then go to next if statement. lastly...
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    Problem regarding voltage regulator.

    Hi Guys, I am using LM 2575 HVT 5.0 as the step down voltage regulator from 12v to 5v. below is the schematic that i used. The problem is the inductor are very hot. It cause the LCD not function properly. What i need to do?
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    Need help in CCS program

    Hi I am connected a missing pulse detector to pin2(RA0) of a PIC16f877a. Basically the missing pulse detector will always given high output, and change to low output if sense missing pulse.It will change back to high after a short period. I need to write a program when the output change to low...
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    Missing Pulse Detetor

    Hi all, I am designing a missing pulse detector. below is the schematic. The incoming signal is about 950Hz. The pulse width is about 600uS and the pause between pulse is 480uS. As i know the width of this output pulse is defined by the values of R2 and C1. R2 and C1 must be chosen such...
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    TSOP4838 and PIC16f877

    Hi all, How to interface TSOP4838 to PIC16f877a? Basically the TSOP4838 output is a square wave if received signal from transmitter and no signal if the signal is obstructed. the result will be show to lcd. The lcd will display increment by one every time the signal is obstructed.
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    automatic room light controller

    Hi Audioguru, So the modulating signal can be check at the pin3 of the 555timer? and also can be check at collector of the transistor. Just that the signal is inverted? thanks
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    automatic room light controller

    Hi Audioguru, I had redesigned another value for R1,R2 and C The burst length is about 615uS and the pause is about 568uS. I think both values passed the requirement stated in the TSOP datasheet. How do you think? my doubt is that the value for burst length too large? thanks
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    automatic room light controller

    Hi Audioguru, I got the idea now. The pause between the burst need to be 10 to 70cycles if i choose 35cycle, the pause will be (1/38Khz * 35) = 0.92ms 1/0.92m = 1.1Khz. So i need to construct another 555 that produce 1.1KHz. Am i correct? After that the output(pin3) of the 555 that produce...
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    automatic room light controller

    Hi Audioguru, Can you provide any schematic to connect to another 555? Does it necessary to care about the burst length and the off time? from the original circuit, its does not use another 555 to on and off the IR transmitter. what happen if i ignore the burst length and the on and off time...
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    automatic room light controller

    Hi Audioguru, For Tsop1738 it is 10cycle/bursts which is same with the Tsop4838. The only difference is for tsop1738:After each burst which is between 10 cycles and 70 cycles a gap time of at least 14 cycles is neccessary. Tsop4838:After each burst which is between 10 cycles and 70 cycles a gap...
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    automatic room light controller

    Hi Audioguru, I had a major problem here. I couldn't get tsop1738 at my area. Can you please recommend any other receiver? can i replace it with tsop1138 since the pin number are exactly the same with tsop1738. Or tsop4838? the pin leg is difference. Tsop1738: pin1=gnd,pin2=Vs,pin3=output...
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    automatic room light controller

    hi Audioguru, you said that "The collector of a transistor also has the received signal but it is inverted." mean that the signal feed into 555 timer is the inverted signal? And the output at pin3 is also the inverted signal? or the signal will be re-inverted back (same as the signal received...
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    automatic room light controller

    Hi all, I have some question regarding this project's schematic. Basically the transmitter will emit a 38Khz signal and receive by the receiver. The receiver will always in low stage when it received the 38khz signal from the transmitter. When there is a object obstructed the signal. The...
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